Portable RhinoBond Hand Welder Designed for Use in Tight Spaces

OMG Roofing Products introduces the RhinoBond Hand Welder. Based on patented Sinch Technology, the portable RhinoBond Hand Welder is designed to help roofers weld RhinoBond Plates in tight spaces such as under raised rooftop equipment and on vertical surfaces. The ergonomically designed tool features a vibrating handle and an indicator light that lets roofers know when the tool is activated and when the weld cycle is complete. The base is recessed and features centering indicator lines to help users properly align the tool over installed RhinoBond Plates for optimum bonding and improved productivity.

The new tool weights just six pounds (2.7 kg), and operates on 110V and 220V power sources for global use. Each tool comes with three, eight-inch tall magnets, and a durable carrying case that protects the induction tool when not in use. Using a 12-gauge RhinoBond Power Cord (sold separately), the independent Hand Welder can be operated up to 100-feet (30 m) from the power source. A quick connect power cord pig-tail enables international users to quickly switch to the local plug configuration for global use (international pig-tails sold separately).

“Many roofers understand the tremendous productivity and performance benefits that RhinoBond offers,” said Web Shaffer, vice president of marketing for OMG. “In fact, some roofers have seen productivity rates increase by 30%. To enhance the systems’ overall productivity, we wanted to offer a solution that can be used everywhere on the roof, even in tight spaces. This new product makes that possible.”

The RhinoBond System is designed for use with TPO and PVC roofing membranes and approved by most roofing system manufacturers. The System uses advanced induction welding technology to bond roofing membranes directly to specially coated plates used to secure the insulation to the deck. The result is a roofing system with improved wind performance that requires fewer fasteners, plates, and seams, and zero penetrations of the new membrane. Since it was introduced in 1998, nearly 2.0 billion square feet (185 million square meters) of membrane has been installed with the RhinoBond System around the world.

For more information, visit OMGRoofing.com.

Single-Ply Roofing Best Practices: Doing Everything Right the First Time.

Figure 1: Designing resilient roof systems is the best of practices. When developing details, we find it very helpful to draft out the roof system (for each different system), noting materials and installation methods. Photos: Hutchinson Design Group

Single-ply membranes have risen from being the “new guy” in the market in the early ’80s to become the roof cover of choice for most architects, consultants and contractors. Material issues have for the most part been resolved, and like no other time in recent history, the industry is realizing a period of relative calm in that regard. Whether EPDM, TPO or PVC, the ease of installation, the cleanliness of the installation (versus the use of hot or cold bitumen), the speed at which they can be installed, and the material costs all blend to make these materials a viable option for watertight roofing covers. But with this market share comes issues and concerns, some of which are hurting owners, giving forensic consultants such as myself too much business, enriching attorneys, and costing contractors and, at times, designers dearly.

Following are some of my thoughts on various issues that, in my opinion, are adversely affecting single-ply membrane roof systems. Paying attention to these issues will bring about best practices in single-ply applications.

Specifying the Roof by Warranty

OMG, can architects do any less? Don’t get me started. The proliferation of “canned” Master Specs which call for a generic 10-year or 20-year warranty and then state to install the product per manufacturer’s guidelines is disheartening. Do

Figure 2: Coordinating with the mechanical engineer in the detailing of the pipe penetrations is critical. Here you can see all the components of the curb, penetrations, roofing and waterproofing are noted. We recommend that the same detail be on the mechanical sheets so that at least an 18-inch curb is known to all. Photos: Hutchinson Design Group

designers realize that manufacturers’ specifications are a market-driven minimum? When architects leave out key details, they are simply relying on the roofing contractor to do what is right. This deserves another OMG. The minimum requirements for a warranty can be very low, and the exclusions on a warranty quite extensive. Additionally, a design that calls for products to be installed based on achieving a warranty may result in a roof system that does not meet the code. Owners are often oblivious to the warranty requirements, and all too often fail to ensure the standard of care until the service life is shortened or there is storm damage — sometimes damage the roof should have withstood if it were properly designed and detailed.

If one is not knowledgeable about roof system design, detailing and specification, then a qualified roof consultant with proven experience in single-ply membranes should be retained. Roof systems and their integration into the impinging building elements need to be designed, detailed and specified appropriately for the building’s intended use and roof function. By way of example, we at Hutchinson Design Group typically design roof systems for a 40- to 50-year service life (see Figure 1); the warranty at that point is nice, but almost immaterial. Typical specifications, which are project specific, cover all the system components and their installation. They are typically 30 pages long and call out robust and enhanced material installations.

More Than the Code

I recently had a conversation with a senior member of a very large and prominent architectural firm in the Chicago area and inquired about how they go about designing the roof systems. The first thing he said was, “We do what is required by code.”

Photo 1: The roof drain sump pans shown here were provided and installed by the plumbing contractor, not the steel deck installer. Having the roof drain level with the top of the roof deck allows for a proper integration of the roof drain and roof system.

What I heard was, “We give our clients the absolute poorest roof the code allows.” An OMG is allowed here again. Does it really need to be said again that the code is a minimum standard — as some would say, the worst you are allowed to design a building by law? Maybe you didn’t realize it, but you are allowed to design above the code. I know this will shock a few of you, but yes, it’s true. Add that extra anchor to prevent wood blocking from cupping. Add extra insulation screw fasteners to improve wind uplift resistance; if too few are used, you may meet the code, but your insulation will be susceptible to cupping. Add that extra bead of polyurethane adhesive. (If I specify 4 inches on center, then perhaps by mid-day, on a hot and humid day, I might get 6 inches on center — as opposed to specifying 6 inches or 8 inches on center, and getting 12 inches on center in spots.) Plan for construction tolerances such as an uneven decks and poorly constructed walls. Allow for foot traffic by other trades. These types of enhancements come from empirical experiences — otherwise known as getting your butt in the ringer. Architects need more time on the roof to observe what goes on.

It’s About Doing What is Right

Doing it right the first time isn’t all that difficult, and it’s certainly less stressful than dealing with the aftermath of doing so little. The cost of replacing the roof in the future could easily be more than double the original cost. Twenty years ago, I

Figure 3: Coordinating with the plumbing engineer, like coordinating with the mechanical engineer, is a requirement of best practices. In this drain detail, we can see the sump pan is called out correctly, and the roof drain, integration of the vapor barrier, extension ring, etc., are clearly defined. Photos: Hutchinson Design Group

chaired an international committee on sustainable low-slope roofing. At that time, the understanding of sustainability was nil, and I believe the committee’s Tenets of Sustainability, translated into 12 languages, helped set the stage for getting designers to understand that the essence of sustainability is long-term service life. That mantra seems to have been lost as a new generation of architects is at the helm. This is unfortunate, as it comes at a time when clients no longer ask for sustainable buildings. Why? Because they are now expected. The recent rash of violent and destructive storms — hurricanes, hail, intense rain, high winds and even wildfires — have resulted in calls for improvement. That improvement is called resiliency. If you have not heard of it, you are already behind. Where sustainability calls for a building to minimize the impact of the building (roof) on the environment, resiliency requires a building (roof) to minimize the impact of the environment on the building. This concept of resiliency requires designing a roof system to weather intense storms and to be easily repaired when damaged. (Think of Puerto Rico and consider how you would repair a roof with no power, limited access to materials, and manpower that might not be able to get to your site.)

Achieving resiliency requires the roof system designer to:

  1. Actually understand that roofs are systems and only as good as their weakest link. Think metal stud parapet and horizontal base anchor attachment; only forensic consultants and attorneys like to see screws into modified gypsum boards.
  2. Eliminate your old, out-of-date, incorrect details. Lead vent flashing and roof cement cannot be used with single-ply membrane.
  3. Design the roof system integration into associated barrier systems, such as where the roofing membrane (air/vapor retarder) meets the wall air barrier. You should be able to take a pencil and draw a line over the wall air barrier, up the wall and onto the roof without lifting it off the sheet. If you cannot, you need to redesign. Once you can, you need to consider constructability and who may get there first — the roofer or air barrier contractor. Then think material compatibility. Water-based air barrier systems don’t react well when hit with a solvent-based primer or adhesive.

    Photo 2: This roof drain is properly installed along with 6 inches of insulation and a cover board. The drain extension ring is 1/2 inch below the top of the cover board so that the water falls into the drain and is not held back by the clamping ring, resulting in ponding around the roof drain.

    Perhaps the roofing needs to be in place first, and then the air barrier brought over the top of the roofing material. This might require a stainless-steel transition piece for incompatible materials. Maybe this requires a self-adhering membrane over the top of the roof edge prior to the roofing work, as some membranes are rather rigid and do not bend well over 90-degree angles. You as the designer need to design this connectivity and detail it large and bold for all to see.

  4. Design the roof system’s integration into the impinging building elements, including:
  • Roof curbs for exhaust fans: Make sure they are insulated, of great enough height, and are not installed on wood blocking.
  • Rooftop unit (RTU) curbs: The height must allow for future re-roofing. Coordinate with the mechanical engineer regarding constructability – determine when the curb should be set and when the HVAC unit will be installed. Roof details should be on both the architectural and mechanical drawings and show the same curb, drawn to scale. Be sure the curb is insulated to the roof’s required R-value. Avoid using curb rails to support mechanical equipment. The flashing on the interior side of the rails may be inaccessible once the equipment is placed. Use a large curb where all four sides will remain accessible.
  • Piping penetrations: Detail mechanical piping penetrations through the roof and support of same, where insulation and waterproofed pipe curbs are needed (see Figure 2). If you are thinking pourable sealer pocket, stop reading and go sign up for RCI’s Basics of Roof Consulting course.
  • Roof curbs, RTU, pipe curbs and rails: Coordinate their location and show them on the roof plan to be assured that they are not inhibiting drainage.
  • Roof drains: Coordination with the plumbing engineer is essential. Sump pans should be installed by the plumbing contractor, not the steel deck installer (see Photo 1), and the location should be confirmed with the structural engineer. Be sure drains are located in the low point if the roof deck is structurally sloped — and if not, know how to design tapered insulation systems to move water up that slope. Do not hold drains off the deck to meet insulation thickness; use threaded extensions. Be sure any air/vapor barrier is integrated into the curb and that the insulation is sealed to the curb. I like to hold the drain flange a half-inch down below the insulation surface so that the clamping ring does not restrain water on the surface. Owners do not like to see a 3-foot black ring at the drain, where ponding water accumulates debris (see Figure 3 and Photo 2).
  1. Understand the roof’s intended use once the building is completed. Will the roof’s surface be used for anything besides weather protection? What about snow removal? Will there be excessive foot traffic? What about mechanical

    Photo 3: Gaps between the roof insulation and roof edges, curbs and penetrations are prevalent on most roofing projects and should be sealed with spray foam insulation as seen here. It will be trimmed flush once cured.

    equipment? Photovoltaic panels? Yes, we have designed roofs in which a forklift had to go between penthouses across the roof. Understanding how the roof will be used will help you immensely.

  2. Understand the construction process and how the roof might be used during construction. It is amazing how few architects know how a building is built and understand construction sequencing and the impact it can have on a roof. I firmly believe that architects think that after a lower roof is completed, that the masons, carpenters, glazers, sheet metal workers, welders, pipe fitters, and mechanical crews take time to fully protect the newly installed systems (often of minimal thickness and, here we go again, without a cover board — OMG) before working on them. I think not. Had the architect realized that temporary/vapor retarders could be installed as work surfaces, getting the building into the dry and allowing other trades to trash that rather than the finished roof, the roof system could be installed after those trades are off the roof.
  3. Coordinate with other disciplines. Roof systems cannot be designed in a vacuum. The architect needs to talk to and involve the structural, mechanical and plumbing engineers to ensure they realize the importance of essential details. For example, we cannot have steel angle around the drain whose flange rests on the bar joist, thus raising the roof deck surface at the roof drain. Ever wonder why you had ponding at the drain? Now you know. I attempt to always have a comprehensive, specific roofing detail on the structural, mechanical and plumbing sheets. I give the other disciplines my details and ask that they include them on their drawings, changing notes as required. That way, my 20-inch roof curb on the roof detail is a 20-inch curb on the mechanical sheets — not a standard 12-inch curb, which would more often than not be buried in insulation.
  4. Detail, detail, detail, and in case you glossed over this section, detail again. Make sure to include job-specific, clearly drawn details. Every condition of the roof should be detailed by the architect. Isn’t that what the client is paying for? Do not, as I once saw, indicate “RFO” on the drawings. Yes, that acronym stands for “Roofer Figure Out.” Apparently, the roofer did not figure it out. I enjoyed a nice Hawaiian vacation as a result of my work on that project, courtesy of the architect’s insurance company. How do you know that a condition works unless you design it and then draw it to scale?

    Figure 4: Insulation to curbs, roof edge and penetrations will not be tight, and to prevent a thermal short, the gaps created in construction need to filled with spray foam, as noted and shown here in this vent detail. Photos: Hutchinson Design Group

    I’ve seen roof insulation several inches above the roof edge because, OMG, the architect wanted gravel stop and forgot about camber. Not too big a deal (unless of course it’s a large building) to add several more layers of wood blocking and tapered edge strips at the now high wood blocking in the areas that were flush, but now the face of the roof edge sheet metal needs to increase. But what if the increase is above the allowable ANSI-SPRI ES1 standard and now a fascia and clip are required? You can see how the cost spirals, and the discussion ensues about who pays for what when there is a design error.

  5. Develop comprehensive specifications that indicate how the roof system components are to be installed. This requires empirical knowledge, the result of time on the roof observing construction. It is a very important educational tool that can prevent you, the designer, from looking like a fool.

Components

Best practices for single-ply membranes, in addition to the design elements above, also involve the system components. Below is a listing of items I feel embodies best practices for single-ply roof system components:

  1. Thicker membranes: The 45-mil membrane is insufficient for best practices, especially when one considers the thickness of the waterproofing over scrim on reinforced sheets. A 60-mil membrane is in my opinion the best practices minimum. Hear that? It’s the minimum. You are allowed to go to 75, 80 or 90 mils.
  2. Cover boards: A cover board should be specified in fully adhered and mechanically attached systems. (Ballasted systems should not incorporate a cover board.) Cover boards have enhanced adhesion of the membrane to the substrate over insulation facers and hold up better under wind load and hail. Cover boards also protect the insulation

    Photo 4: The greatest concern with the use of polyurethane adhesives is that the insulation board might not be not fully embedded into the adhesive. Weighting the boards at the corners and center with a minimum of 35 pounds for 10 minutes has proven to work well in achieving a solid bond.

    from physical damage and remain robust under foot traffic, while insulation tends to become crushed. Cover boards are dominated by the use of mat-faced modified gypsum products. Hydroscopic cover boards such as fiberboards are not recommended.

  3. Insulation: Now here is a product that designers seldom realize has many parts to be considered. First, let’s look at compression strength. If you are looking to best practices, 25 psi minimum is the way to go. The 18-psi insulation products with a fiber reinforced paper facer can be ruled out entirely, while 20 psi products are OK for ballasted systems. Now let’s look at facers. If you think about it for a second, when I say “paper-faced insulation,” you should first think “moisture absorbing” and secondly “mold growth.” Thus paper-faced products are not recommended to be incorporated if you are using best practices. You should be specifying the coated glass-faced products, which are resistant to moisture and mold resistant. A note to the manufacturers: get your acts together and be able to provide this product in a timely manner.

Additional considerations regarding insulation:

  • Insulation joints and gaps: You just can’t leave joints and gaps open. Show filling the open joints at the perimeter and curbs and around penetrations with spray foam in your details and specify this as well (see Photo 3 and Figure 4).
  • Mechanical attachment: Define the method of attachment and keep it simple. On typical projects, I commonly specify one mechanical fastener every 2 square feet over the entire roof (unless more fasteners are needed in the corners). Reducing the number of fasteners in the field compared to the perimeter can be confusing for contractors and the quality assurance observer, especially when the architect doesn’t define where that line is. The cost of the additional screws is nominal compared with the overall cost of the roof.
  • Polyurethane foam adhesive: Full cover spray foam or bead foam adhesive is taking over for asphalt, at least here in the Midwest, and I suspect in other local markets as well. The foam adhesive is great. It sticks to everything: cars, skylights, clerestories, your sunglasses. So, it is amazing how many insulation boards go down and don’t touch the foam. You must specify that the boards need to be set into place, walked on and then weighted in place until set. We specify five 35-pound weights (a 5-gallon pail filled with water works nicely), one at each corner and one in the middle for 10 minutes (see Photo 4). Yes, you need to be that specific.
  1. Photo 5: The design of exterior walls with metal studs that project above the roof deck is a multi-faceted, high-risk detail that is often poorly executed. Here you can see a gap between the deck and wall through which warm moist air will move and result in the premature failure of this roof. The sheathing on the wall cannot hold the horizontal base anchor screw, and the joints in the board allow air to pass to the base flashing, where is will condense. This is the type of architectural design that keeps on giving — giving me future work.

    Vapor/air barrier: A vapor air barrier can certainly serve more than a function as required for, say, over wet room conditions: pools, locker rooms, kitchens, gymnasiums. We incorporate them in both new construction and re-roofing as a means of addressing construction trade phasing and, for re-roofing, allowing time for the proper modification of existing elements such as roof edges, curbs, vents, drains, skylights and pipe curbs. Be sure to detail the penetrations and tie-ins with wall components.

  2. Deck type: Robust roof decks are best. Specify 80 ksi steel roof decks. Try staying away from joint spacing over 5 feet. Decks should be fully supported and extend completely to roof edges and curbs.
  3. Roof edge design: A key aesthetic concern, the termination point for the roof system, the first line of defense in regard to wind safety — the roof edge is all of these. The construction of the roof edge on typical commercial construction has changed drastically in the last 20 years, from brick and block to metal stud. Poorly designed metal stud parapets will be funding my grandkids’ college education. The challenge for the metal stud design is multifaceted: It must close off the chimney effect, prevent warm moist air from rising and condensing on the steel and wall substrate, create an acceptable substrate on the stud face in which to accept base anchor attachment, and — oh, yes — let’s not forget fire issues. Tread lightly here and create a “big stick” design (see Photo 5).
  4. Roof drains and curbs: As discussed above, there is a great need for coordination and specific detailing here. The rewards will be substantial in regard to quality and efficiency, minimizing time spent dealing with “what do we do now” scenarios.
  5. Slope: Design new structures with structural roof deck slope, then fine tune with tapered insulation.

Final Thoughts

Best practices will always be a balancing act between cost and quality. I believe in the mantra of “doing it right the first time.”

The industry has the material and contractors possess the skill. It’s the design and graphic communication arm that needs to improve to keep everyone working at the top of their game.

Designers, get out in the field and see the results of your details. See firsthand how a gypsum-based substrate board on a stud wall does not hold screws well; how a lap joint may not seal over the leading edge of tapered insulation; how the roof either ponds water at the roof drain or doesn’t meet code by drastically sumping; or how the hole cut in the roof membrane for the drain might be smaller than the drain bowl flange, thus restricting drainage. Seeing issues that the contractors deal with will help you as the designer in developing better details.

Contractors, when you see a detail that doesn’t work during the bidding, send in an RFI and not only ask a question, but take the time to inform the architect why you don’t think it will work. On a recent project here in Chicago, the architect omitted the vapor retarder over a pool. The contractor wrote an explicit explanation letter and RFI to the architect during bidding, and the architect replied, “install as designed.” In these situations, just walk away. For me, this is future work. A local contractor once told me, “I don’t get paid to RFI, I get paid to change order.” He also said, “If I ever received a response to an RFI, I would frame it!”

Manufacturers, too, can raise the bar. How about prohibiting loose base flashings at all times, and not allowing it when the salesman says the competition is allowing it. Have contractors on the cusp of quality? Decertify them. You don’t need the hassles. Owners don’t need the risk.

Seek out and welcome collaboration among contractors, roof systems designers, knowledgeable roof consultants, and engineers. Learning is a lifelong process, and the bar is changing every year. Too often we can be closed off and choose not to listen. At HDG, I am proud to say we have the building owners’ best interests at heart.

By all working together, the future of single-ply membranes can be enhanced and the systems will be retained when the next generation of roof cover arrives — and you know it will.

Three Sioux City Community School District Projects Are Part of Long-Term Plan

In 2017, Winkler Roofing crews re-roofed portions of two high schools and one elementary school. Shown here is an aerial photo of East High School. Photos: Mule-Hide Products Co. Inc.

For the Sioux City Community School District (SCCSD) in Sioux City, Iowa, the final dismissal bell of the school year marks more than the start of summer break for students and staff. It also signals the beginning of roofing season.

In addition to routine maintenance and repairs, each summer brings at least one major roofing project for the district and its 24 facilities. Existing roofs that have fallen out of warranty coverage are replaced. The district also has completed a steady stream of construction projects over the past 16 years, replacing aging schools to meet evolving needs.

District enrollment has increased by several hundred students over that timeframe and now stands at more than 14,500. SCCSD also has expanded its programming, creating specialty elementary schools focusing on STEM (science, technology, engineering and math), computer programming, environmental sciences, the arts, and dual-language education in English and Spanish. These specialties continue with middle school exploratory classes and eventually lead to the Sioux City Career Academy, which offers numerous education pathways to help students prepare for postsecondary education and careers.

Aerial view of West High School. Photos: Mule-Hide Products Co. Inc.

“Our facilities need to keep up with the curriculum and new technologies so we can provide the best possible learning environments for our students,” says SCCSD Director of Operations and Maintenance Brian Fahrendholz, adding that the facilities plan emphasizes both supporting student achievement and maintaining fiscal responsibility.

Winkler Roofing Inc. of Sioux City has been one of the district’s key partners in this process for more than 20 years, installing new or partial roofing systems on nearly every building in the district. The summer of 2017 saw its crews re-roof portions of two high schools and one elementary school, installing 335 squares of new TPO roof systems and removing 170 tons of ballast.

A crew of between six and nine professionals was on a jobsite at any given time. The three projects were completed in less than a month, beginning in late June and wrapping up in late July. And there was nothing on the punch list following the warranty inspections.

A Systematic Approach

In recent years, SCCSD has adopted a systematic, long-range-planning approach to roof system management, working with local architects to evaluate its facilities, identify and plan work that needs to be completed the following summer, and map out future projects. The three roofs replaced in 2017 were indicative of this approach.

TPO Bonding Adhesive is applied on the substrate and the back of TPO membrane. Photos: Mule-Hide Products Co. Inc.

Each of the roofs was between 15 and 20 years old and had begun to show signs of age. Their manufacturers’ warranties had also expired in recent years, making their replacement next up on the district’s roofing project schedule.

“We typically replace roofing systems within five years of the warranty expiration,” Fahrendholz explains. “It enables us to stay ahead of the maintenance issues that can begin cropping up.”

All three existing roofs had ballasted EPDM roofing systems. The re-roofing projects continued the district’s move toward TPO systems and, where possible, eliminating ballast. The three new roofing systems have 20-year, no-dollar-limit labor and material warranties.

SCCSD has several reasons for moving away from ballasted systems, according to Winkler Roofing President Jeff Winkler, P.E. In addition to reducing the roof’s weight and eliminating the cost of the ballast, unballasted roofs have a neater appearance and it is easier to monitor the membrane’s condition and find and repair any leaks. And, of course, when the time for re-roofing comes, there are no truckloads of ballast to remove and replace.

According to Winkler, SCCSD likes the durability of TPO membranes. “They like that the membrane is reinforced and that the seams are heat-welded, rather than seamed with primer and tape,” Winkler notes.

East High School Project

Re-roofing a 5,356-square-foot section at East High School entailed a complete tear-off of the existing ballasted EPDM roofing system and insulation down to the steel roof deck. The Winkler Roofing team then installed a new system topped with Mule-Hide TPO with CLEAN Film from Mule-Hide Products Co. It was the first time Winkler Roofing had installed the prodcut.

At East High School, polyisocyanurate insulation is installed using 3-inch galvalume plates and drill point fasteners. Photos: Mule-Hide Products Co. Inc.

Three layers of polyisocyanurate insulation were mechanically fastened with screws and plates to enhance the building’s energy efficiency. The 60-mil TPO membrane was then fully adhered using TPO Bonding Adhesive from Mule-Hide Products.

The last step in any well-done TPO project is removing the dirt and scuffs that are inevitably left behind during installation, notes Winkler. That step is eliminated with this product; the crew simply removes the protective film covering the membrane to reveal a clean roof that is ready for inspection.

“The material is more expensive than regular TPO membranes, but there is the potential to make up for that in reduced labor costs,” Winkler notes.

The biggest benefit would be seen on roofs that have fewer penetrations, according to Winkler. Installing the membrane around penetrations requires removing a portion of the protective film, he explains. Because those areas are then exposed to scuffs and dirt, crews must go back and clean them by hand.

West High School Project

Meticulous detail work was key to the successful replacement of a 18,056-square-foot section of the roof at West High School. There were nearly four dozen penetrations in the roof, from 4-inch pipes to HVAC equipment measuring 8 feet by 12 feet. Many of the chimney stacks also were in spots that were awkward for the crew to work around.

Winkler Roofing crew members prepare to install a TPO walkway pad. Photos: Mule-Hide Products Co. Inc.

It was all in a day’s work for the Winkler Roofing team. “The quality of our detail work is one of the things we take pride in,” Winkler says. “The keys are good leadership, both on and off the roof, and a well-seasoned crew. My foreman, Absalon Quezada, is a master of solving the toughest of details and coordinating a well-orchestrated crew.”

The roof’s existing concrete deck made a mechanically attached system uneconomical, so a new ballasted system was specified. The existing ballast had deteriorated to the point that, if reused, it could puncture the new roofing membrane. So, all 100 tons of it, along with the existing EPDM membrane, were removed and disposed of. The pieces of stainless steel cap metal along the perimeter were removed and numbered in sequence for reinstallation later. Sections of water-damaged insulation were removed and replaced.

An additional layer of polyisocyanurate insulation was loose-layered over the entire roof to improve energy efficiency, followed by a new loose-layered 60-mil white TPO membrane. New ballast was then installed.

Details such as this pipe boot were installed using a hot-air welder. Photos: Mule-Hide Products Co. Inc.

The crew navigated a challenging site while depositing the new ballast on the roof of the one-story building. The site offered only one feasible parking spot for the seven dump trucks that would deliver the rock, and that was on a lawn, just on the other side of two large trees. Crews carefully noted the location of sprinklers for the in-ground irrigation system to avoid driving over them, and shut the system down for several days in advance of the delivery to minimize ruts caused by the trucks’ tires. The trees’ trunks were spaced less than 20 feet apart and the canopies have grown together, leaving only small tunnel to feed the conveyor through. Crews kept the conveyor low as they extended it through the branches, then brought it to roof height by repeatedly raising it and the backing the truck up.

Riverside Elementary School Project

At Riverside Elementary School, a 7,314-square-foot section of roof was replaced with a 60-mil, fully attached TPO system.

The existing EPDM membrane, ballast and edge metal flashings were removed and disposed of. Crews removed and replaced any water-damaged insulation, added an additional layer of polyisocyanurate insulation throughout to increase the building’s energy efficiency, and mechanically attached the insulation to the steel roof deck using screws and plates. The white TPO membrane was then installed using bonding adhesive, and new edge metal flashings were added.

Straight A’s on the Report Card

The new roofs received top grades on their inspection report cards.

At East High School, crews installed Mule-Hide TPO with CLEAN Film from Mule-Hide Products Co. The last step in the installation process is removing the protective film covering the membrane. Photos: Mule-Hide Products Co. Inc.

When Mule-Hide Products Co. Territory Manager Jake Rowell inspected the roofs, there were no items on his, or the district’s, punch list. The only remaining task — which was completed during the inspection — was covering the seams on the West High School roof with ballast; they had intentionally been left exposed for easy inspection. In fact, that was the only “to-do list” item Rowell noted during inspections of 11 Winkler Roofing projects that week.

“The quality of their work is phenomenal,” Rowell says. “The crews take pride in their work. They don’t just throw a project together and move on. They check their work to make sure it’s done right before I see it and before the customer sees it.”

THE TEAM

Roofing Contractor: Winkler Roofing Inc., Sioux City, Iowa
Architect: FEH DESIGN, Sioux City, Iowa, www.fehdesign.com
Roofing Materials Distributor: ABC Supply Co. Inc., www.abcsupply.com
Decorative Sheet Metal: Interstate Mechanical Corp., Sioux City, Iowa, www.interstatemechanicalcorp.com

MATERIALS

TPO Membrane Roof Systems: Mule-Hide Products Co. Inc., www.mulehide.com

Metal Roof and Wall Panels Capture the Spirit of Shakespearean Theater

The Otto M. Budig Theater is the home of the Cincinnati Shakespeare Company. The new theater was designed by GBBN Architects in Cincinnati. Photos: Petersen Aluminum Corp

For many new arenas and theaters, the sheer size and scope of the project can pose the biggest hurdles. At the new Otto M. Budig Theater, home of the Cincinnati Shakespeare Company, the problem was the reverse. The intimate theater was shoehorned into an existing space up against an adjacent building, so logistics were tight. But that didn’t mean the roof system couldn’t be striking. Designed by GBBN Architects in Cincinnati, the building’s exterior features daring angles and multi-colored metal roof and wall panels that combine to help capture the spirit of the Shakespearean theater.

Matt Gennett, senior project manager and vice president of Tecta America Zero Company in Cincinnati, oversaw the roofing portion of the new construction project in the Over the Rhine section of Cincinnati on the corner of Elm Street and 12th Street. “This building was plugged in downtown, and they fit everything in real tight,” he says.

Approximately 5,400 square feet of PAC-CLAD 7/8-inch, 24-gauge Corrugated Panels from Petersen Aluminum Corp. were installed on the metal roofs and walls. Tecta America Zero Company installed the metal roof systems, as well as a TPO roof manufactured by Carlisle SynTec over the main structure and mechanical well. Work began in January of 2017 and the roofing portion of the project was wrapped up in late August.

The Metal Roof System

The building features two different metal roof systems. The roof on the Elm Street side is comprised of three intersecting triangle-shaped sections in two colors, Champagne Metallic and Custom Metallic Bronze. “There were several unique angles on the roof,” Gennett explains. “On the top, there was a second metal roof, a shed roof that went down to the 12th Street side.”

The theater’s roof and walls feature approximately 5,400 square feet of PAC-CLAD 7/8-inch Corrugated Panels from Petersen Aluminum Corp. in two colors. The wall panels are perforated. Photos: Petersen Aluminum Corp.

The metal roof systems were installed over a 2-inch layer of polyisocyanurate insulation and a 2-1/2-inch nail base from Hunter Panels, H-Shield NB. The nail base is a composite panel with a closed-cell polyisocyanurate foam core, a fiber-reinforced facer on one side and, in this case, 7⁄16-inch oriented strand board (OSB) on the other. The nail base was topped with Carlisle WIP 300 HT waterproofing underlayment to dry in the roof.

Crews also installed two rows of snow guards on the metal roof using the S-5! CorruBracket. “The snow guard was a little different,” Gennett says. “It was specifically designed for a corrugated roof.”

The TPO Roof System

The main roof and mechanical well were covered with the TPO roof system, which totaled approximately 8,300 square feet. After Carlisle VapAir Seal725 TR self-adhering air and vapor barrier was applied to the metal deck, crews installed two layers of 2-inch iso. Tapered insulation was applied over the top to ensure proper drainage. The insulation was covered with a 1/2-inch sheetrock and the 60-mil TPO was fully adhered.

Two large smoke hatches manufactured by Bilco were installed over the stage area. The ACDSH smoke hatches measured 66 inches by 144 inches, and are designed for theaters, concert halls and other interior applications that require limiting noise intrusion.

The Installation

The initial focus was to get the roof dried in so work could progress inside the building. The jobsite conditions posed a few challenges. The structure abutted an existing building, and the space was tight. The schedule necessitated multiple trips to the site, which can be a budget-buster on a small project. “We had a lot of trips in and out to accommodate the schedule and get everything dried in so they could meet the interior schedule,” notes Gennett. “We were sort of on call. We made three or four trips out to roof this small project, so it took a lot of coordination because it was completed in pieces.”

Crews tackled the TPO roof sections first. The mechanical well section provided several challenges. Changes in the mechanical well layout necessitated moving some curbs and making adjustments to the tapered insulation. “They were trying to get lot of equipment into a small space,” Gennett explains. “We had to make sure we could get the water to the low spots and route it around all of that equipment. That was probably the biggest challenge on the project.”

Staging material was also problematic, as traffic was heavy and parking space was at a premium. Material was loaded by a crane, which had to be set up in the street. “It’s a postage stamp of a site,” says Gennett. “This is a main thoroughfare, and there is a school right across the street. We had to work around school hours, and we couldn’t be working when the busses were coming in. We usually came in after school started, around 8 a.m., to load materials.”

When it came time to load the metal panels, the cramped jobsite actually paid off. “It was very convenient,” Gennett recalls. “We were able to load the panels onto the adjacent roof and just hand them over. We had a nice staging area for cutting, so all in all it wasn’t bad.”

The corrugated panels were installed with matching edge metal. “It’s not a complicated panel to install, and they look really nice,” Gennett notes. “On the Elm Street side, to the right of the valley was one color, and to the left was another, so we had to match the color with our coping. There were some interesting transitions with our metal. We also had to really pay attention to how the siding was being installed so we could match the metal to the siding and follow the transitions from color to color.”

The perforated wall panels were installed by ProCLAD Inc. of Noblesville, Indiana. “Once the walls were done, we came in and did the transition metal,” Gennett says. “We just had to make sure everything lined up perfectly.”

Planning Ahead

Ensuring a safe jobsite was the top priority for Tecta America Zero and Messer Construction, the general contractor on the project. “Both Messer Construction and Tecta America take safety very seriously. That’s why we’re good partners,” Gennett says. “We had PPE, high-visibility clothing, hard hats, safety glasses for the whole project. All of the guys were required to have their OSHA 10. Anyone outside of the safety barriers had to be tied off 100 percent of the time.”

Planning ahead was the key to establishing the safety plan and meeting the schedule while ensuring a top-quality installation. “This job had a lot of in and out, which is tough in the roofing business,” Gennett says. “But we planned ahead, we made sure everything was ready for us when we mobilized, and we did a good job of coordinating with the other trades. It took a lot of meetings and discussions — just good project management.”

Gennett credits the successful installation to a great team effort between everyone involved, including the general contractor, the subcontractors, and the manufacturers. “We pride ourselves on our great, skilled crews and our great field project management,” he says. “Our superintendents are there every day checking the work and making sure the guys have everything they need. Messer Construction is great to work with, and obviously having the manufacturer involved the project and doing their inspections as well helps ensure the quality meets everyone’s standards and holds the warranty.”

The theater is now another exciting venue in the Over the Rhine neighborhood. “It is really cool spot,” Gennett says. “It’s an up-and-coming neighborhood that’s grown in leaps and bounds in the last seven years. There is a ton going on in Cincinnati. It’s just another part of the city that makes it really fun to go downtown.”

TEAM

Architect: GBBN Architects, Cincinnati, Ohio, www.gbbn.com
General Contractor: Messer Construction, Cincinnati, Ohio, www.messer.com
Roofing Contractor: Tecta America Zero Company, Cincinnati, Ohio, www.tectaamerica.com
Wall Panel Installer: ProCLAD Inc., Noblesville, Indiana, www.procladinc.com

MATERIALS

Metal Roof:
Roof Panels: PAC-CLAD 7/8-inch Corrugated Panels, Petersen Aluminum Corp., www.pac-clad.com
Wall Panels: PAC-CLAD 7/8-inch Corrugated Panels, Petersen Aluminum Corp.
Nail Base: H-Shield NB, Hunter Panels, www.HunterPanels.com
Snow Guards: CorruBracket, S-5!, www.S-5.com
Waterproofing Underlayment: Carlisle WIP 300 HT, Carlisle SynTec, www.CarlisleSyntec.com

TPO Roof:
Membrane: 60-mil grey TPO, Carlisle SynTec
Waterproofing Underlayment: Carlisle WIP 300 HT, Carlisle SynTec
Smoke Hatches: ACDSH Acoustical Smoke Hatch, The Bilco Co., www.Bilco.com

Plate Marking Tool Designed to Increase Installation Efficiency

OMG Roofing Products introduces a plate marking tool designed to help roofers improve rooftop productivity by quickly locating and marking RhinoBond Plates installed under thermoplastic membranes.  

The new RhinoBond Plate Marking Tool is lightweight, simple-to-use and easy-to-maneuver. Simply roll the marking tool over a row of installed RhinoBond Plates. Every time it passes over a properly installed plate, the tool leaves a temporary mark on the surface of the membrane to identify the plate location. Plate marks are made with standard blue construction crayons and typically fade away within a few weeks.

The plate marking tool is compatible with all thermoplastic membranes regardless of type or thickness. In addition, the tool’s handle is reversible for quick direction changes, and lays flat for rolling under rooftop pipes and raised equipment such as air handling units. Other benefits of the new system include powerful sweeper magnets mounted on the front and back of the chassis that pick-up any metal debris on the roof. The tool is provided in a protective carrying case for easy handling and storage.

The RhinoBond System is designed for use with TPO and PVC roofing membranes. The System uses advanced induction welding technology to bond roofing membranes directly to specially coated plates that secure the insulation to the deck. The result is a roofing system with improved wind performance that requires fewer fasteners, plates, and seams, and zero penetrations of the new membrane.

For more information, visit OMGRoofing.com.

School Board’s Kite-Shaped Building Reflects Location’s History

The roof design for the Homewood Board of Education Central

The roof design for the Homewood Board of Education Central Office was inspired by the site, which is known as Kite Hill. Photos: Petersen Aluminum Corp.

The new home for the Homewood Board of Education Central Office in Alabama is a 14,500-square-foot modern structure that marks the first phase of a long-term development plan on a 24-acre site in Homewood, Ala., a suburb of Birmingham.

The contemporary structure was designed by Williams Blackstock Architects in Birmingham. “The roof design was inspired by the site, which is known as Kite Hill,” says architect Kyle Kirkwood. “It’s a spot where kids and parents come to fly kites. The roof, which slopes in two different directions and is kite-like in its appearance, is representative of the popular site.”

The building was conceived as a “garden pavilion” integrated within the site, intended to mediate between public and private property, and man-made and natural materials. The structure is nestled into a line of pine trees with a cantilevered roof extending just beyond the pines.

The design incorporates approximately 24,000 square feet of Petersen’s PAC-CLAD material in four different profiles. The main roof includes 16,000 square feet of Petersen’s Snap-Clad panels up to 60 feet long. The design also incorporates an interior application of the Flush panels by integrating them into the lobby area. In addition, 7,000 square feet of Flush panels were used in soffit applications. The panels were manufactured at Petersen’s Acworth, Ga., plant.

The roof design was complex, Kirkwood notes. “Since the roof slopes in two directions, we had an interesting valley situation where we had to coordinate the orientation of the seams,” Kirkwood said.

Challenging Installation

The roof also features two rectangular low-slope sections that were covered with a TPO system manufactured by Firestone Building Products. The roof systems were installed by Quality Architectural Metal & Roofing in Birmingham, which specializes in commercial roofing, primarily architectural metal and single-ply projects.

The building is nestled into a line of pine tree

The building is nestled into a line of pine trees near the edge of the site, adjacent to a residential area. The cantilevered roof was designed to help the structure blend in with the location and mediate between public and private property. Photos: Petersen Aluminum Corp.

Eddie Still, Quality Architectural Metal & Roofing’s vice president, helped prepare the budget for Brasfield and Gorrie, the construction manager on the project, so Still was prepared to go when his bid was accepted. “It was a job that consisted of a large portion of metal and a smaller portion of TPO,” he says. “Since we do both things, we were a good fit.”

The installation was made event tougher by the logistics of the site, according to Still. “The design of the metal roof was unusual, to say the least,” he says. “It had a valley that cut through it, and the panels were sloped in two directions. That’s not normally the case.”

The biggest obstacle was posed by the building’s location on a hill near the edge of the property line, immediately adjacent to a residential neighborhood. “The Snap-Clad panels were approximately 60 feet long, which isn’t a problem if you have the equipment to handle them,” Still notes. “It does pose a problem logistically when it comes to getting them into a tight area, and we definitely had that.”

Panels were trailered in and hoisted to the roof by a crane. “Once the panels were up there, the installation was fairly easy,” Still says. “The roof didn’t have a lot of changes in elevation or different plateaus built into it. The only quirky thing was that valley, and once you had that squared away, you were good to go.”

Coordinating penetrations with members of plumbing and HVAC trades is critical, according to Still. “On the metal roofs, we always stress that you’re trying to present an aesthetic picture for the building, so you want to minimize the penetrations so it looks cleaner,” he says. “You have to coordinate on site so if you have a plumbing exhaust stack, it comes up in the center of the pan and not on the seam.”

The metal roof incorporates approximately 24,000

The metal roof incorporates approximately 24,000 square feet of Petersen’s PAC-CLAD material in four different profiles. In addition, 7,000 square feet of Flush panels were used in soffit applications. Photos: Petersen Aluminum Corp.

A small section of metal roof near the entryway was made up of mechanically seamed panels. “The reason we used Tite-Loc panels on that portion of the roof was because of the low slope,” Still says. “We used the same width panel, so it looks identical, but the seams are different. They are designed to work on systems with slopes as low as ½:12.”

Quality Architectural Metal & Roofing also installed the Firestone self-adhered TPO roof system on two low-slope sections of the roof, totaling approximately 3,000 square feet.

Still looks back on the completed project with pride. “Our niche would be a building like this one, which has TPO or some other membrane roofing and metal,” he says. “We’ve been in business 33 years. We have a well-deserved reputation for the type of work we do. In the bid market things are price driven, so more often than not, price is the determining factor. But in larger projects and work that’s negotiated, the G.C. is going to opt to choose people to solicit pricing from who have a history of doing successful projects with them.”

TEAM

Architect: Williams Blackstock Architects, Birmingham, Ala., Wba-architects.com
Construction Manager: Brasfield and Gorrie, Birmingham, Brasfieldgorrie.com
General Contractor: WAR Construction Inc., Tuscaloosa, Ala., Warconstruction.com
Roofing Contractor: Quality Architectural Metal & Roofing Inc., Birmingham, Qualityarch.com
Metal Roof System Manufacturer: Petersen Aluminum Corp., Pac-Clad.com
Low-Slope Roof Manufacturer: Firestone Building Products, FirestoneBPCO.com

North Carolina Middle School Generates More Energy Than It Uses

Sandy Grove Middle School in Hoke County, N.C.

Sandy Grove Middle School in Hoke County, N.C., was designed to be an energy-positive building. It generates 40 percent more energy than it consumes. Photo: Mathew Carbone Photography

When Robbie Ferris first presented the idea of a school building that generates more energy than it uses, people were skeptical. Now he can point to Sandy Grove Middle School in Hoke County, N.C., as proof that a high-performance school building can go well beyond net zero and generate 40 percent more energy than it consumes.

Ferris is the president of SfL+a Architects and manager at Firstfloor, a development company that specializes in public-private partnerships and design-build-operate agreements. “We designed the building, we own it and we lease it to the school district,” he says. “We monitor all of the systems remotely. One of the reasons we do that is because when you put really high-performance systems in buildings, you have to make sure they are operating at peak efficiency. It can take time to make sure everything is optimized.”

Three years after completion, Sandy Grove Middle School is outperforming its energy models, and the building continues to win accolades. It recently received Energy Star 100 Certification and has been recognized as the nation’s most energy positive school.

“Sandy Grove Middle School is a perfect example of a high-performance facility,” says Ferris. “With the public-private lease-back model, everyone wins. The students receive a quality school, it fits in to the school system budget, and it is energy efficient to help both total cost and our environment.”

The building’s systems were designed to be as energy-efficient as possible, and that includes the roof, which features an array of photovoltaic (PV) panels to generate electricity. “We wanted a roof that would last 30 years,” Ferris notes. “We’ve had a tremendous amount of success with TPOs, and metal roofs as well. This particular client wanted a metal roof look from the front, but they were very open to a membrane roof on other parts of the building. We made the decision to put the metal roof on the front of the building and a TPO on the wings at the back of the building.”

On this project, the warranties were important considerations, along with durability and energy efficiency. SfL+a specified a standing seam metal roof system manufactured by Dimensional Metals Inc. and a TPO system manufactured by GenFlex. “Obviously, if you’re putting a couple of million dollars’ worth of solar panels on your roof, you want to make sure you have a roof that is going to be problem free.”

A Smooth Installation

The installation was a challenging one, but everything went smoothly, notes Aaron Thomas, president and CEO of Metcon Inc. Headquartered in Pembroke, N.C., Metcon is a full-service general contractor that specializes in energy positive commercial buildings, so it was perfectly suited to serve as the construction manager on the project.

Photovoltaic panels were installed

Photovoltaic panels were installed on both the standing seam metal roof and the TPO system. The systems on the low-slope roof sections are fully ballasted, and both sections were installed without penetrating the roof system. Photo: SfL+a Architects

Thomas and Ryan Parker, senior project manager with Metcon, coordinated the work of subcontractors on the job, including the Youngsville, N.C. branch of Eastern Corp., which installed the TPO and metal roofs, and PowerSecure, the solar installer on the project, based in Wake Forest, N.C.

The roof systems covered 85,000 square feet, and Sharp PV panels were installed on both the metal roof and the TPO system. Solar panels were also installed on freestanding structures called “solar trees.” Each solar tree is 20 feet tall, 25 feet wide and weighs 3,200 pounds.

“The TPO roof system was upgraded to an 80-mil product due to solar panels being added to the roof,” Parker notes. “It was 100 percent ballasted on the low-slope sections, with slip sheets being used below the racking on the TPO roof.”

On the metal roof, clips manufactured by S-5! were used to affix the solar racking to the seams. “There are no penetrations for the frames, and penetrations for the electrical wiring went through vertical walls, not the roof,” Parker says. “There were no penetrations anywhere in the roof system, which made all of the warranties that much easier to keep intact.”

The biggest challenges on the project, according to Parker, were coordinating the different scopes of work and ensuring all of the manufacturers’ warranty considerations were met. “We had two different kinds of roofs, both coupled with solar panels,” Parker says. “Like any rooftop with photovoltaic products, there had to be special attention paid to the warranties of all parties involved. Both Genflex and DMI were closely involved in coordinating details to ensure that the owner achieved a great roof free of defects.”

The building’s systems were designed for energy efficiency

The building’s systems were designed for energy efficiency, and the roof features an array of photovoltaic panels to generate electricity. Photo: Mathew Carbone Photography

One key was developing a detailed schedule and keeping everyone on it. “We would meet once a week and huddle up on how it was progressing and what else needed to be done,” Parker recalls. “We found that by using a collaborative submittal sharing platform, all of the varying parts and pieces could be checked by all parties to ensure compatibility.”

There were multiple safety concerns associated with combining solar panels to the roofing system, so everyone had to be on the same page. “The roofing subcontractor and the solar subcontractor performed a joint safety plan that utilized common tie off points,” Parker notes. “The job had zero lost time.”

“Everyone coordinated their work and it was a great team effort,” Ferris says. “It was one of the smoothest jobs I’ve ever seen. We have not had a single leak on that project—not a single problem.”

Proof Positive

For Ferris, the greatest obstacle on energy-positive projects convincing members of the public and governmental agencies of the benefits. “The biggest challenges had nothing to do with construction; they had to do with just doing something new and different,” he says. “The toughest challenge was getting the school board, the county commissioners, the public and the review agencies on board. It took a very long time—and lots of meetings.”

Photo: SfL+a Architects

Now Ferris can point to Sandy Grove as an example of just how a high-performance school building can pay huge dividends. “As soon as you see it in real life, you’re on board,” he says. “It’s very exciting for people to see it. If we can get people to the school, they’ll walk away convinced it is the right thing to do.”

With Sandy Grove, the school district has a 30-year lease with an option to purchase. Ferris believes the lease model is the perfect solution for educators. “We’re responsible for any problems for the life of the lease,” he says. “If a problem does come up, we usually know about it before the school does because we monitor the systems remotely online.”

“In their world, buildings are a distraction from educating kids,” Ferris concludes. “This is one building that is not a distraction.”

TEAM

Building Owner: Firstfloor, Inc., Winston-Salem, N.C., Firstfloor.biz
Architect: SfL+a Architects, Raleigh, N.C., Sfla.biz
Construction Manager: Metcon Inc., Pembroke, N.C., Metconus.com
Roofing Contractor: Eastern Corp., Youngsville, N.C.
Photovoltaic Panel Installer: PowerSecure, Wake Forest, N.C., Powersecure.com
Metal Roof System Manufacturer: Dimensional Metals Inc., DMImetals.com
TPO Roof System Manufacturer: GenFlex Roofing Systems, GenFlex.com

Self-Adhered TPO Membrane Offers Easy Installation With No VOCs

UltraPly TPO SA Firestone Building Products offers UltraPly TPO SA with Secure Bond Technology, a self-adhering membrane with a factory-applied, pressure-sensitive adhesive. Designed to be the next generation in fully adhered roof system application, Secure Bond Technology ensures adhesion coverage across the membrane, establishing one of the strongest bonds possible. According to the company, this advanced technology not only significantly improves installation speed over traditional fully adhered applications, but allows installation in temperatures as low as 20 degrees Fahrenheit. With no Volatile Organic Compounds (VOCs), UltraPly TPO SA with Secure Bond Technology is safe for the contractor, building occupants and the environment. 

Hot-Air Welding Under Changing Environmental Conditions

The robotic welder’s speed, heat output and pressure should be properly programmed before the welding process begins. Photo: Leister.

The robotic welder’s speed, heat output and pressure should be properly programmed before the welding process begins. Photo: Leister.

Today’s most powerful hot-air welders for overlap welding of thermoplastic membranes are advertised to achieve speeds of up to 18 meters (59 feet) per minute. That’s fast enough to quickly ruin a roofing contractor’s day.

These robotic welders are digitally monitored to achieve consistent overlap welding performance, but they cannot adapt to changing environmental conditions automatically. It’s the contractor’s job to monitor and assess seam quality before the base seam is welded and when ambient temperatures or other factors potentially influence welding performance.

Successful hot-air welding requires the use of specialized, properly maintained and adjusted equipment operated by experienced personnel familiar with hot-air welding techniques. Achieving consistent welds is a function of ensuring that the roofing membrane surface is clean and prepared for heat welding, conducting test welds to determine proper equipment settings, and evaluating weld quality after welding has been completed.

Setting up hot-air robotic welders properly is the key to having a properly installed thermoplastic roof, and performing test welds is one of the most important steps. Making appropriate adjustments before the welding process begins ensures that the correct combination of welder speed, heat output and pressure is programmed into the robotic welder.

For most roofing professionals, these procedures have been firmly established in the minds of their crews and equipment operators through education and field training. But let’s not forget that Murphy’s Law often rules on both large and small low-slope roofing projects.

The frightening reality about using robotic welders is if they are set-up incorrectly or environmental conditions change, the applicator may weld thousands of feet of non-spec seam before anyone even bothers to check. If you probe for voids at the end of the day, it is probably too late.

If serious problems are discovered, the applicator must strip in a new weld via adhesive, cover tape, or heat welding, depending on what the membrane manufacturer will allow. If seams must be re-welded, the operator has to create not one, but two robotic welds on each side of the cover strip. The sheet will also need to be cleaned and re-conditioned no matter what method is used.

Can these errors be corrected? Absolutely. Except now the crew is in a real hurry because the roofer is working on his own time, and application errors tend to snowball under these conditions.

Reality Check

What goes on in the field is sometimes quite different than what one sees when hot-air welding thermoplastics under an expert’s supervision.To support this view, we asked four field service reps, each with a minimum of 35 years of roofing experience, to comment. The most senior “tech” has worked for six different thermoplastic membrane manufacturers in his career. Their names shall remain anonymous, but this writer will be happy to put readers in touch with them upon request.

Successful hand welding is a skill that is developed and refined over time. The correct selection of welder temperature and nozzle width can have a significant effect on the quality of the hand weld. Photo: GAF.

Successful hand welding is a skill that is developed and refined over time. The correct selection of welder temperature and nozzle width can have a significant effect on the quality of the hand weld. Photo: GAF.

So, let’s welcome Christian, Dave, Mark and Walter, and get straight to the point: Is the average roofing crew diligent enough when it comes to properly testing welds using industry best practices?

“I would say ‘probably not,” exclaims Walter. Dave just shakes his head as his colleague Mark adds, “I would have to say no.”

Considering the generally laudable performance of thermoplastic membranes over the last decade or so, we must interpret our experts’ opinions as suggesting the need for further improvement in hot-air welding techniques. Hence, the purpose of this article.

“There are a few outstanding issues causing bad welds,” says Walter. “These include welding over dirty or contaminated membranes; improper equipment setup; using crews with inadequate training; and knowing the difference between the weldability of various manufacturers’ membranes.”

Welding equipment consists of three main components: the power supply, the hot air welder (either automatic or hand-held), and the extension cord. A stable power supply of adequate wattage and consistent voltage is critical to obtaining consistent hot air welds and to prevent damage to the welder.

The use of a contractor-supplied portable generator is recommended, although house-supplied power may be acceptable. Relying on power sources that are used for other equipment that cycle on and off is not recommended. Power surges and/or disruptions and insufficient power may also impact welding quality. Proper maintenance of welding equipment is also of obvious importance.

“Contractors seem to never have enough power on the roof,” observes Mark. “The more consistent your power is, the more consistent your welds will be. Too many times, I’ve seen too many tools (hand guns, auto welder, screw guns and a RhinoBond machine) plugged into one generator.”

Generator-induced challenges on the jobsite are going to arise, agrees Christian. “But at least today there is more experience in understanding, dealing with, and ultimately preventing these issues,” he says.

Most TPO and PVC membrane suppliers also recommend using the latest automatic welding equipment, which provides improved control of speed, temperature and pressure. Our four experts generally agree that field welding performance has improved over the years and programmable robotic welders have helped. They also point to proper training and experience as crucial factors.

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TPO System Delivers Energy Efficiency for Company Headquarters

TurnKey Corrections constructed a new 115,000-square-foot in facility in River Falls, Wis.

TurnKey Corrections constructed a new 115,000-square-foot in facility in River Falls, Wis.

If you want it done right, do it yourself. Company owners Todd Westby and Tim Westby take a hands-on approach to running TurnKey Corrections, the River Falls, Wisconsin-based company that provides commissary and jail management services to county corrections facilities nationwide. The Westby brothers also take pride in the fact that TurnKey manufactures the kiosks it provides to its clients and develops and owns the proprietary software used to run them.

So, it’s perhaps not surprising that, when building the company’s new headquarters, Todd Westby, the company’s CEO, founder and general manager, served as the general contractor. Or that he had definite ideas regarding the roofing system that would be installed. Or that he was more than willing to get his hands dirty during the installation process.

Founded in 1998, TurnKey Corrections helps corrections facilities streamline and lower the cost of delivering a variety services to inmates, including commissary, email and email-to-text communication, video visitation, law library access, and paperless intra-facility communication and documentation. Following several years of robust growth, the company had outgrown its three existing buildings. So, it constructed a new 115,000-square-foot facility to bring all operations, including 50,000 square feet of office space and a 65,000 square-foot warehouse where commissary items are stored prior to shipment to corrections facilities, under a single roof and accommodate future success.

“We wanted to be involved in the project from beginning to end so we knew what we were getting and how it was built,” Todd Westby says of the decision to keep construction management in-house. “We wanted to know about anything and everything that was being built for the company in this building.”

In planning the project, Westby initially set two key criteria for the roofing system: that the building would be made watertight as quickly as possible so concrete slab pours and other interior work could be completed, and that the roof would be covered by a warranty of at least 20 years. The design-build firm’s initial plans called for a ballasted EPDM roofing system, but Rex Greenwald, president of roofing contractor TEREX Roofing & Sheet Metal LLC of Minneapolis, suggested a white TPO system, noting that it would meet the quick installation and warranty goals while also enhancing the building’s energy efficiency. Westby was intrigued and, after some research, agreed to the recommendation. In addition to helping reduce cooling costs during summer months, the reflective surface would allow a blanket of snow to remain on the roof during winter months to provide additional insulation.

The TPO roofing system was constructed over a 22-gauge metal fabricated roof deck.

The TPO roofing system was constructed over a 22-gauge metal fabricated roof deck.

The Roof System

The TPO roofing system included a 22-gauge metal fabricated roof deck; two 2.5-inch-thick layers of Poly ISO insulation from Mule-Hide Products Co., with tapered insulation saddles and crickets to aid drainage; and 811 squares of 60-mil white TPO membrane from Mule-Hide Products Co. The insulation and membrane were mechanically attached using the RhinoBond System from OMG Roofing Products. Cast iron roof drains, designed and installed by a plumber, were used rather than scuppers and downspouts—a practice that the TEREX team strongly recommends to prevent freezing during the cold Upper Midwest winters. Walkways lead to the mechanical units, protecting the membrane from damage when maintenance personnel need to access the equipment.

The TEREX team finds the RhinoBond System to be the most efficient and economical attachment method for TPO systems. Specially coated metal plates are used to fasten the insulation to the roof deck and then an electromagnetic welder is used to attach the membrane to the plates. The membrane is not penetrated, eliminating a potential entry point for moisture. And while other mechanical attachment methods require the crew to seam as they go, the RhinoBond System allows them to lay the entire membrane (a task which must be completed in good weather conditions) at once and go back later to induction weld the seams and plates, which can be done when Mother Nature is slightly less cooperative.

Greenwald estimates that the switch from the originally specified ballasted EPDM system to the TPO roofing system and RhinoBond System shaved at least 10 percent off the installation time and reduced the roof weight by 10 pounds per square foot.

Having Westby on-site as the general contractor also sped up the project considerably, Greenwald notes. “He was a huge asset to all of the subcontractors,” he explains. “We could get construction questions answered quickly and could talk through issues and procedures on a timely basis.”

And the most memorable moment in the project for Greenwald was seeing Westby working side-by-side with his crew. “One day we had a delivery truck show up, and Todd jumped on the forklift and helped us unload the truck.”

As sought from the project’s outset, the roofing system is backed by a 20-year, no-dollar-limit labor and material warranty.

With one winter of use in the rearview mirror, the roofing system has exceeded Westby’s expectations. Warehouse space was doubled, but heating costs have been cut in half. The 10-unit heating system also is able to keep the warehouse a uniform temperature, without the cold spots that were common in the old building.

“It really is a beautiful, very efficient and organized-looking roof,” Greenwald says.