Are You Meeting Thermal Insulation Code Requirements?

Photo 1. Conditions such as this, in which the fastener plates melt the snow, visually demonstrate the heat loss that is a known entity to roof installers and knowledgeable roofing professionals.

You may have overheard conversations such as this:

New Building Owner: “You promised energy conservation and savings.”

Mechanical Engineer: “We sized the mechanical unit based on the code required effective thermal value.”

New Building Owner: “But why are my cost 30 percent above your estimates and I am needing to run my units constantly and they still barely maintain a comfortable environment?”

Mechanical Engineer: “We have checked all the set points and systems and they are all working, albeit with a bit of laboring. We don’t know why there is not enough heat.”

New Building Owner: “Well, someone is going to have to pay for this!”

Scenarios and liability questions like this are being repeated across the northern North American continent, and to mechanical engineers, architects and owners, the cause is a mystery. Perhaps they should have talked to seasoned roofing professionals and consultants. They could’ve told them that many mechanically attached roofs, incorrectly promoted and sold as energy-saving systems, were actually energy pigs. One only needed to walk a mechanically attached roof with a few inches of snow on it to see the heat loss occurring. It doesn’t take scientific studies and long-winded scenarios to prove this — just get up on the roof and see it. (See Photo 1.)

Photo 2. When a light dusting of snow blew off this 2 million-square-foot facility in central Illinois, every single mechanical fastener and insulation joint could be identified by the ice visible at their locations. This roof needed to be replaced due to condensation issues several years after installation at a cost of more than $10 million.

I spoke on this topic back in 2007 at the RCI Cool Roofing Symposium. I always like being a soothsayer, and several recent studies are demonstrating and attempting to quantify this energy loss that most roofers could tell you was there.

For years the NRCA suggested a loss of thermal value of 7 percent to 15 percent through the joints in a single-layer insulation application and through mechanical fasteners used to secure the insulation. (The NRCA has since removed this figure and suggests that professionals be consulted to determine thermal heat loss.) The NRCA recommended a cover board to reduce this effect. This was at a time when roof covers were predominantly BUR, modified bitumen or adhered single plies. The upsurge in mechanically attached single-ply membranes, brought on by low-cost installation and the promise of energy savings, changed the game. No one was asking, if there could be a loss of 7-15 percent when mechanically attaching insulation, what could the effective R-value loss be when we install thousands of fasteners and plates 12 inches on center (or less) down a membrane lap seam? Gee, haven’t we seen that before?

Code Requirements

The code and standard bodies — ICC, IECC, ASHRAE — have been repeatedly raising required thermal insulation values over the past decade in an attempt to conserve energy; that is their intent. They listened to astute designers and

Photo 3.This is close-up of the roof shown in Photo 2. Heat loss through the screws and fastener plates and through joints in the single layer of insulation melted the snow. The water froze when the temperatures dropped and the ice was revealed when a light wind pillowed the membrane and the remaining snow blew away.

prescribed two layers of insulation, and then again to determine the minimum R-value and not allow averages. The intent is clear. The required R-value per ASHRAE zone is to be achieved.

Their goals were laudable, but not all roof systems achieved the in-place R-values required. So, this article is in part an attempt to educate code officials and explain the need for a change.

Words can explain the phenomenon of thermal loss, but photos are worth a thousand words, and since my editor has told me that I cannot have a 4,000-word article, I leave it to the photos to do the talking. (See Photos 2, 3 and 4.)

Scientific Studies

In their Buildings 2016 article titled “Three-Dimensional Heat Transfer Analysis of Metal Fasteners in Roofing Systems,” Singh, Gulati, Srinivasan and Bhandari (Singh) studied the effect of heat transfer through thermal bridging (mechanical fasteners) in various roof assembly scenarios.

Their study exposes a shortfall in many standards that have as their goal a reduction in energy loss through building envelope systems through prescriptive approaches. For roofing assemblies, standards prescribe a minimum R-value, but they do not take into consideration the heat loss that happens though metal fasteners. There are no guidelines or recommendations in regards to thermal loss, including the loss of heat through roof system fasteners. It’s actually ignored.

Figure A: The effect of mechanical fasteners below the roof cover in mechanically attached roofs is not negligible as considered by general standards. As can be seen here for systems 1A and 1 B, in which mechanical fasteners are used in the lap seams of the roof cover (systems 3A and 3B have the fasteners below a layer of insulation), the actual thermal value loss caused by mechanical fasteners can be as high as 48 percent, as seen in system 1A with a high density of mechanical fasteners. As the mechanical fastener density decreases (1B), the heat loss also decreases. Thus, a correlation appears to exist in which heat loss due to thermal bridging is proportional to the fastener density.

The results of the Singh study, as seen in the graph (Figure A), show that the effects of thermal shorts, e.g., mechanical fasteners used to secure the roof cover, is not negligible. In fact, thermal shorts can result in a loss of 48 percent of the effective value. Read that again! The thermal value of the roof insulation layer on which the mechanical engineer has in part sized the mechanical equipment — and which the owner is counting on for significant energy savings — could be about half of what was assumed. Add in gaps and voids, and the loss in the effective R-value could top 50 percent. What that means is that to achieve the code required R-30, say in Chicago, mechanically fastened roof systems need to have R-45 in the design to meet the effective code required R-value. This last sentence is for the code bodies — are you listening?

The value of this study cannot be underestimated, as thousands of buildings have been constructed since its publication that would not meet an effective R-value check in a commissioning study.

Changing the Code

The energy inefficiency of mechanically attached roof systems in ASHRAE zones 4 and above has been known to roofing crews for decades. Now, with the requisite scientific studies completed, the codes need to be revised to reflect the inherent thermal loss through mechanical fasteners. Additionally, studies from Oak Ridge National Laboratory highlight the energy increase required with inherent air changes below the membrane, confirming the need for air/vapor barriers on the deck on mechanically attached roof assemblies. (See “The Energy Penalty Associated with the Use of Mechanically Attached Roofing Systems,” by Pallin, Kehrer and Desjarlais.)

Photo 4: Heat loss also occurs through adhered roofs when the insulation is mechanically attached.

As a starting point for code groups and officials, I suggest the following code revisions:

  1. State that if a mechanically attached roof cover is being used that the prescribed thermal R-value shall be increased by 50 percent.
  2. State that if a mechanically attached roof cover is being used that an air barrier below the insulation must be used and that it shall be fully adhered to penetrations and roof perimeters.

Closing Thoughts

The goal of energy conservation is a laudable one. The American Institute of Architects’ goal of zero-energy building by 2030 will never be met until real-world empirical information can be presented at code hearings. (For those of you who do not attend code hearings or know the process, information is usually disseminated in two-minute sound bites without documentation.) This lack of information sharing is a travesty and has resulted in numerous code changes that have been detrimental to the goal of energy savings. Time has come for a new way of thinking.

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.

Polymer Shakes Mimic Cedar while Protecting Historic Estates

When it was time for homeowners at the historic Fleur du Lac Estates in Homewood, Calif., to select new roofing materials, they looked for a product that would mimic the look of cedar but bring them advantages to protect their homes and buildings from Mother Nature. After a comprehensive search, they determined that the Class A fire and Class 4 impact ratings of Bellaforté polymer shake tiles from DaVinci Roofscapes met their needs.

The Class A fire and Class 4 impact ratings of the Bellaforté tiles bring peace-of-mind to residents within the Fleur du Lac Estates, Homewood, Calif.

The Class A fire and Class 4 impact ratings of the Bellaforté tiles bring peace-of-mind to residents within the Fleur du Lac Estates, Homewood, Calif.

A prime filming location for the 1974 movie “Godfather II,” Fleur du Lac Estates is now a private condominium development located on the beautiful west shore of Lake Tahoe. A Yacht Club and Boat House, 22 individual homeowner units and a variety of shared recreational facilities make the historic 1938 compound a much-sought-after retreat.

Fire Resistance a Prime Benefit

Years of harsh weather conditions took their toll on the real cedar shake roofs at Fleur du Lac Estates. Damage from repeated leaks, hail, ice dam issues, snow and other weather conditions recently convinced the board of directors it was time to invest in new roofs for the entire estate.

“We started with our two most valuable community structures, the Yacht Club and Boat House,” says Stewart Dalie, maintenance supervisor and project manager at Fleur du Lac Estates. “Our plans are to reroof all of the buildings in the Tahoe Blend over the next five to seven years. We did a tremendous amount of research to determine what roofing products would look realistic in this setting, meet the new codes required for roofs in our area, yet offer us superior qualities and a long life span.

“Selecting the fire- and impact-resistant Bellaforté shake material from DaVinci Roofscapes means we won’t have to be concerned with the potential spread of flames should our area ever be touched by wildfires. That’s a huge concern for our geographic area. However, not having to worry about wind-blown embers landing on a roof and then catching the building on fire is a tremendous relief.”

The Class A fire and Class 4 impact ratings of the Bellaforté tiles bring peace-of-mind to residents within the community. The durable roofing tiles have the appearance of natural hand-split cedar shake with slanted sawn edges and staggered lengths, but with the hassle-free qualities of a manufactured product. At a 1-inch average tile thickness, Bellaforté Shake roofing tiles remind many residents of jumbo cedar shakes prevalent in the Lake Tahoe area.

The Bruce Olson Construction team incorporated snow fences and snow guards from Rocky Mountain Snow Guards into the structures.

The Bruce Olson Construction team incorporated snow fences and snow guards from Rocky Mountain Snow Guards into the structures.

Safeguarding a Historic Setting

It’s not surprising that homeowners at the upscale Fleur du Lac Estates want to invest in the best possible roofing material. This is a mountain and lakeside homeowners association where every home has a deeded slip in the marina, resort-style services are the norm and aesthetics of the community are vigilantly upheld.

Originally the summer home of famous industrialist Henry J. Kaiser, the 15-acre lake-shore site was constructed beginning in 1938. After Kaiser sold the estate, it went through a series of transitional uses from the 1960s to 1979, including serving as a private school and as the site for many on-location scenes for Francis Ford Coppola’s film, “The Godfather II.” Only in the 1980s did the current project begin to refurbish existing key structures and transform original homes on the property to individually owned homes.

“Our community has always embraced the history of this setting while looking toward protecting its future,” says Lane Murray, general manager at Fleur du Lac Estates. “That’s one of the key reasons we wanted a roofing product that has the look of real cedar shakes but with manmade advantages like resistance to fire, impact and high winds.”

Superior Roofing Installation

Despite a variety of challenges with removing the old roofs and prepping for the new synthetic shake tiles, the team at Bruce Olson Construction, Olympic Valley, Calif., has successfully tackled their first DaVinci Roofscapes installation project at Fleur du Lac Estates.

“The roofing surface for the Yacht Club and Boat House were in bad shape and very uneven,” says Taylor Greene, general manager of Bruce Olson Construction. “We had to plane these into workable surfaces before getting started. Once we got started the product installed beautifully. We added flashing material to cover some valley locations, which made the project look exceptional. To achieve the realistic look, gable end flashing that concealed the manufactured edge of the DaVinci product was added.”

The company, which does residential and multifamily new construction, works in several states, including Hawaii. It has already started work on several additional roofs in the Fleur du Lac complex.

“The Bellaforté roofing looks amazing,” Greene says. “Best of all, these polymer shakes are perfect for this geographic area. Traditional wood shakes ‘hold’ the water from melting snow. Those saturated shakes weigh more and cause the freeze line to be a part of the shake. With the DaVinci product, the water is not absorbed into the tile, so snow melting is faster and more efficient. This can also help reduce the ice damming effect in many locations.”

Laughing at Mother Nature

Nestled amidst stunning mountain peaks and world-famous ski conditions, Fleur du Lac Estates can experience heavy snowfall during the winter months. The property is just five minutes from Homewood Mountain Ski Resort and the area usually sees snow in excess of 180 inches total. That’s one reason why the community decided to have the Bruce Olson Construction team incorporate snow fences and snow guards from Rocky Mountain Snow Guards into the structures.

“In our area it’s very common to use snow guards and fences to help keep snow from falling on individuals and property,” Greene explains. “The previous structures at Fleur du Lac Estates didn’t have any type of snow-retention system. We believe having these products in place now—which were very simple to put in during the polymer shake installation—will make life much easier for property owners no matter how much snow Mother Nature delivers each season.”

Rocky Mountain Snow Guards custom designed the snow-retention system for Fleur du Lac Estates, incorporating its Drift III+ snow fences and Rocky Guard RG10 snow guards. The system was developed to handle the 180-PSF snow load that can occur in this geographic location.

“The snow guards are attached in a pattern above the snow fence that creates friction to hold the snow ‘slab’ in place while the snow fence provides a barrier beyond which the snow slab won’t slide,” says Lars Walberg, president of Rocky Mountain Snow Guards. “Using the combination of snow guards and snow fences gives this project a balanced snow-retention system that has the ‘look’ the owners desired.”

For homeowners, the new Bellaforté roofs on the Yacht Club and Boat House are tempting reminders of what will be on their own homes in the years to come.

“Now that the Yacht Club and Boat House roofs are complete we’re hearing very positive comments from our residents,” Murray says. “Folks are eager for the work to continue in the common areas so that their individual homes can soon get these terrific-looking new roofs!”

ICC and ASHRAE Outline Roles for Development of International Green Construction Code

In a deal nearly two years in the making, the International Code Council (ICC) and ASHRAE have signed the final agreement that outlines each organization’s role in the development and maintenance of the new version of the International Green Construction Code (IgCC) sponsored by the American Institute of Architects (AIA), ASHRAE, ICC, the Illuminating Engineering Society (IES) and the U.S. Green Building Council (USGBC). The code, scheduled to be released in 2018, will be powered by ANSI/ASHRAE/ICC/IES/USGBC Standard 189.1, Standard for the Design of High-Performance, Green Buildings Except Low-Rise Residential Buildings developed using the American National Standards Institute (ANSI) approved ASHRAE consensus process. The joint Standing Standards Project Committee 189.1 (SSPC) will serve as the consensus body that will work to ensure the standard is consistent and coordinated with the ICC Family of Codes.

The ICC will be responsible for Chapter 1, Scope and Administration. For the 2018 IgCC, ICC will coordinate the technical provisions developed by ASHRAE with the provisions in Chapter 1 of the 2015 IgCC. As a result, the 2016 Group B Cycle will not include Chapter 1 of the IgCC for code changes. With ASHRAE developing technical provisions, ICC’s 2017 Group C cycle to develop the 2018 IgCC has been cancelled. Part of the development process for the 2018 technical provisions will include the SSPC review of the 2015 IgCC and consideration of content for inclusion in 189.1-2017 along with changes generated by the committee and proposals submitted by stakeholders. Following the completion of the 2018 IgCC, Chapter 1 of the IgCC will be developed by ICC using its consensus code development process.

“Our goal in this partnership all along has been to share resources to increase use of the IgCC and make it simpler for code officials, designers and contractors to build environmentally efficient structures that will lessen energy and water consumption and reduce the carbon footprint,” said ICC Board President Guy Tomberlin, CBO. “We are now situated to do just that. We thank our partners, ICC Members and all who will contribute to the development of the IgCC powered by 189.1.”

The Executive Steering Committee for the effort to align 189.1, the IgCC and LEED consists of representatives of ICC, ASHRAE, USGBC, AIA and IES, and the SSPC Chair.

“The full integration of Standard 189.1 to serve as the technical content of the IgCC will leverage ASHRAE’s technical expertise and increase the standard’s influence on sustainable buildings,” notes ASHRAE President David Underwood. “We look forward to continuing to engage a broad spectrum of stakeholders in development of Standard 189.1 following the ANSI consensus standards development process. The result will be a comprehensive compliance tool that can be used by jurisdictions worldwide that are committed to a more sustainable built environment.”

The new publication also will align the Leadership in Energy & Environmental Design (LEED) rating system program to ensure a streamlined, effective set of regulatory and above-code options. The green building certification program recognizes best-in-class building strategies and practices. To receive LEED certification, building projects satisfy prerequisites and earn points to achieve different levels of certification

“This joint initiative will forge the fundamental regulatory building blocks of green construction on which future green building leadership initiatives can grow,” says Brendan Owens, chief of engineering at USGBC. “It takes courage to think differently and to commit to a new model, and for that we thank the leadership of the partner organizations behind the IgCC powered by 189.1.”

“Our combined membership, consisting of practicing design professionals, code officials, and the building industry representatives, supports the development of codes and standards that protect the health, safety and welfare of the public at large,” says AIA CEO Robert Ivy, FAIA. “Through this significant agreement, both the AIA and the ICC agree to work more closely to achieve our common goals.”

In 2010, ASHRAE and ICC joined forces by making 189.1 an alternative compliance path for the IgCC. The new agreement between ASHRAE and ICC furthers the effort these organizations initiated in 2010 by providing the market with a single code that is coordinated with the International Family of Codes.

“IES looks forward to continuing to partner with ASHRAE in developing technical content for Standard 189.1,” according to Rita Harrold, IES representative. “And to participating with the other organizations in this unique collaborative opportunity to satisfy the goals for the new version of IgCC.”

The agreement creates a comprehensive framework for jurisdictions looking to implement and adopt green building regulations and codes. The unprecedented collaboration leverages the unique organizational expertise of the partners participating in this evolution of green building codes and brings AIA, ASHRAE, ICC, IES and USGBC into strategic and tactical alignment on the relationship between 189.1 and the IgCC. Other organizations that support this vision and would like to join the effort are invited to contact Dominic Sims or Jeff Littleton.

Are You ‘PV Ready’?

Commercial rooftops are an attractive platform for the installation of solar photovoltaic (PV) electricity-producing systems. These low-slope roofs offer an economical and sustainable structural foundation for renewable solar energy. As an example, one of the largest roof-mounted PV systems in North Carolina has been online for several months at the Old Dominion Freight Line Inc. vault logistics facility in Thomasville. Almost 7,700 solar panels completely cover the warehouse’s 160,000-square-foot roof and produce enough power (1.8 megawatts) to offset more than 90 percent of the building’s annual energy costs.

Success stories like Old Dominion’s are becoming increasingly common in the sunny Carolinas. However, it is important to remember a roof’s function is, first and foremost, to protect the building’s contents and people from the elements. In this regard, roofing professionals need to anticipate the potential risks associated with the installation of a roof-mounted PV system (array). This sort of due diligence is particularly important when installing PV systems on existing warranted roofs.

A broad selection of membranes and thicknesses are available for consideration when a PV installation is planned. Photo courtesy of GAF, Wayne, N.J., and Protech Roofing Service, San Diego

A broad selection of membranes and thicknesses are available for consideration when a PV installation is planned. Photo courtesy of GAF, Wayne, N.J., and Protech Roofing Service, San Diego

To help in these industry efforts, members of Waltham, Mass.-based SPRI—the trade association that represents sheet membrane and component suppliers to the commercial roofing industry—have developed “PV Ready” roof assemblies and guidelines designed to provide maximum protection for the roof (and maintain its warranty coverage).

In September, SPRI’s technical committee and board of directors also approved and distributed to its members Technical Bulletin 1-13A, “Summary of SPRI Membrane Manufacturer Photovoltaic (PV) Ready Roof Systems and Services”. The bulletin contains general guidelines from SPRI related to “PV Ready” roof assemblies. This article goes into more depth about issues related to PV installations, particularly on existing warranted roofs.

Ask the Right Questions

The installation of a PV system on an existing warranted roof raises many important questions for the roofing professional and building owner. For example, will the roof accommodate the added weight of the PV array? Logistically speaking, before property owners decide on a solar-power system, they will need to determine whether their roofs are sturdy enough to support
the additional loads put on the existing roof structure by the solar array.

An average solar panel and support system typically add a minimum of 3 to 4 pounds per square foot to the existing roof. It is the responsibility of the roofing professional to ensure this additional weight does not exceed the load limits determined by the building’s designer.

From an economic (life-cycle-cost) point of view, it makes sense the service life of the existing roof membrane will come close to matching the projected service life of the PV system. If not, a complex and costly reroofing project may be required long before the solar panels need to be replaced. In general, the underlying roofing system must provide the same minimum investment horizon—generally at least 25 years—to realize the full potential of the rooftop PV system.

Most PV arrays require penetrating the roof membrane. Even non-rack-type systems may include electrical conduits, wiring and other components that may need to be flashed in a professional manner. It is essential the responsibility for this flashing work rests with the roofing contractor.

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