Steep-Slope Projects: Risks, Considerations and Best Practices for Contractors

Photos: Atlas Roofing

Photos: Atlas Roofing

Many contractors treat residential roofing as routine. However, whether a re-roof or new construction, each project can be infinitely complex and should be addressed as such by always accounting for weather and safety issues, as well as proper installation and customer service.

One of the most prominent and popular elements of residential architecture is a steep-slope roof. According to the Occupational Safety and Health Administration (OSHA), steep-slope roofs have slopes greater than 4:12 and range from 18.5 degrees to 45 degrees or more. While the process of installing a roof with these angles isn’t necessarily much different from a low-slope roof, it can pose more risks and considerations for workers.

Weather Woes

Weather plays an important role in every roofing project, but staying on top of potential issues from Mother Nature is especially crucial during steep-slope jobs.

Photos: Atlas Roofing

Photos: Atlas Roofing

In high temperatures, workers may fall victim to heat cramps, heat exhaustion, heatstroke or worse. The best way to beat the heat is to start early and get as much done as possible before the temperature peaks. Starting early in the summer—specifically in the South—can allow work to be completed before daily rain showers roll in. Proper hydration and attire are also important.

Cold temperatures can create even more complications because some manufacturers advise against installing their products in weather below 45 degrees Fahrenheit and certain equipment is susceptible to freezing. Furthermore, workers have to pay extra attention to the grip of their shoes to avoid slipping and falling. Not to mention, freezing-cold hands and feet may cause an otherwise adept worker to become clumsy. Wearing the proper clothing is key during cold-weather jobs, and workers should be advised to keep an eye out for the first signs of frostbite, including cold skin, redness, tingling and numbness.

Safety Considerations

In 2015, falls were the leading cause of private-sector work deaths in the construction industry, accounting for nearly 40 percent of worker fatalities, according to OSHA. In addition, OSHA reports nearly 90 percent of fatal falls happen due to the lack of a fall-protection system.

Photos: Atlas Roofing

Photos: Atlas Roofing

When working on a roof slope greater than 4/12, OSHA requires additional safety measures, which include either a guardrail system with toeboards, safety net systems or personal fall arrest systems. Yet, many contractors—especially residential roofers—choose to forgo protective devices because they feel they are not feasible or create a greater hazard. In such cases, OSHA does allow the use of alternative fall-protection methods in residential construction, as long as contractors develop a written, job-specific fall-protection plan that complies with OSHA regulations.

Proper Installation

During the installation process, roofers should keep a few things in mind whether they’re applying shingles to a steep-slope or low-slope structure.

  • Valleys
Photos: Atlas Roofing

Photos: Atlas Roofing

Valleys are a critical part of proper roof installation because they experience the most water flow during rainstorms and can be potential leak points.

In an open valley, a piece of aluminum, copper or other type of metal is used to help keep rainwater flowing off the roof. Open valleys are often used when a homeowner wants a showier look, such as on a Colonial-style home.

Closed valleys—the most common valley installation method—use asphalt shingles and offer a more traditional look. When properly installed, they keep water from getting trapped in the valley and allow for proper drainage.

In addition to open and closed valleys, contractors also have the option to create a weave valley, which alternates shingles through the valley from both sides, creating a braid-like effect.

Laminate/architectural shingles should not be used for weave valleys. Because laminate shingles aren’t one-dimensional, they do not create the flat surface needed for a weave valley, which should only be used with three-tab shingles.

When using laminate shingles, be sure to follow instructions on the wrapper for either an open or closed application.

Contractors also need to be extremely careful around obstacles such as chimneys and skylights, which require their own flashing and water divergence methods. For instance, more flashing may be needed in these areas to divert water and prevent leaks.

  • Starter Shingles

Starter shingles allow the first course of shingles to properly seal down, protecting the edge of the roof and providing anchoring power for high-wind resistance at the critical eave and rake areas. They further protect the roof by filling in spaces under the cutouts and edges for the first course of exposed shingles, preventing wind uplift.

Photos: Atlas Roofing

Photos: Atlas Roofing

The most common mistake when installing starter shingles or modifying traditional three-tab shingles is putting them on backward or upside-down.

Additionally, the overhang should be no more than three-quarters of an inch to prevent wind from penetrating beneath shingles, as well as to keep shingles from curling or cracking.

In addition, many manufacturers caution against double-stacking pallets of starter shingles, which can cause the bottom shingles to warp. Be sure to read all storage and handling instructions prior to installation.

  • Underlayment

Underlayment is an important part of the roofing process and is required by code for residential properties to meet Class A fire requirements. Serving as a secondary barrier, underlayment protects rakes, eaves and critical flashings from water infiltration. Most warranties also require underlayment for the roof to be ASTM compliant. However, some contractors still opt not to use it because they want to save time on a project or their customer balks at the cost.

Photos: Atlas Roofing

Photos: Atlas Roofing

Another frequent error during underlayment installation is incorrect overlaps. On low-slope roofs (slopes between 2:12 and 4:12), underlayment should have double coverage. And while traditional installation is fine on steep-slope roofs, always follow manufacturer instructions for overlaps from course to course.

Last but not least, be sure to keep underlayment from wrinkling, which can cause ripples in the shingles. While trying to keep underlayment as flat as possible, avoid pulling it too tight because it has a natural expansion and contraction. If underlayment gets wet, be sure it adequately dries out before continuing the installation process.

  • Shingles and Nails

Shingles should be installed with the manufacturer’s recommended offset, which will help prevent leak points and also properly align the shingles across the roof. Once all of the shingles are aligned, only the shingles themselves should be exposed—not the nails.

Because the common bond area is the strongest part of a shingle, manufacturers require nails be placed there to achieve the advertised wind performance. Nails should not be too high or too low, or unevenly spaced. If nails aren’t positioned correctly, the manufacturer’s wind warranty may not be valid.

Customer Service Follow-Up

Providing excellent customer service is key to every roofing job. Homeowners who have a good experience are more likely to share positive reviews and opinions.

Photos: Atlas Roofing

Photos: Atlas Roofing

Before starting a steep-slope project, be sure to discuss the entire process with homeowners to ensure that they know what to expect, as well as the types of warranties they will receive with their new roof. In addition, prepare the surrounding property, such as windows and landscaping, to prevent damage during the installation process.

During the job, be sure workers are vigilant about not dropping nails anywhere on the jobsite. After the job, walk the property with the homeowners to ensure all debris and materials were cleaned up; magnets can be used to double-check for stray nails. If the homeowners are happy with the finished product and their experience, don’t be afraid to ask them to write a nice review on the company website, Angie’s List, Yelp or other customer referral app.

Most of the best practices for steep-slope roofing can be applied to any type of roofing project. However, steep-slope work can pose additional challenges that other projects may not. Always follow manufacturer’s instructions and OSHA guidelines on all roofing jobs, but especially on steep-slope projects, when one minor slip could turn into major consequences for all involved.

 

Feeling Comfortable With Metal Roofing

Metal Roof Consultants Inc

Photo: Metal Roof Consultants Inc.

Theodore Roosevelt once said, “The best thing you can do is the right thing; the next best thing you can do is the wrong thing; the worst thing you can do is nothing.” 

Throughout our lives, we must decide what to do and how to deal with the inevitable fear that surrounds doing anything for the first time. Remember that bicycle in the garage that looked so inviting—until you thought of how it would be impossible for you to balance yourself on those two tiny wheels and pedal it forward without falling and hurting yourself. Your mind focused on falling and not the excitement of being able to conquer riding that bicycle. Yet, as Theodore Roosevelt said many years ago, “the worst thing you can do is nothing.” 

We are faced with new things throughout our lives, and when we do we usually must weigh the possibilities of doing the right thing, the wrong thing, or nothing. However, if we expect to have a productive and peaceful life, we must force ourselves to always do “something.”  

Finally, we must also ask ourselves why we even consider new things we contemplate doing. When we take on a new task and we know why we are doing it, we are comfortable with taking whatever risk is anticipated. When we know that the only wrong thing to do is nothing, we have the possibility to achieve even greater things. Even if it turns out to be the wrong thing, we will learn valuable lessons about ourselves and the task we were trying to accomplish.  

Now, let’s look at the metal roofing industry and ask ourselves whether we are “doing nothing” either because we are afraid of “falling off the bicycle” or because we haven’t determined why we want to enter this market. Both reasons limit your personal and business potential to what you are doing now. Now, let’s explore some of the reasons you might not be comfortable entering the metal roof market, thereby limiting your growth potential. 

The Metal Market

Metal roofing has been around since 1932, when the first standing seam roof panel was introduced by Armco steel at the World’s Fair in Chicago. However, it is still a rather small percentage of the total roofing market. Why? In part, it’s because some contractors fear entering this market. Let’s look at some of the reasons that the unknown aspects of metal roofing, or the incorrect perception of a metal roofing system, can cause contractors to avoid this market: 

Metal Roof Consultants Inc.

Photo: Metal Roof Consultants Inc.

Specialized workforce. There is the perception that this market requires a field force that is very difficult to gather. The reality is that the metal roofing systems in today’s market include parts and components that are easily put together. Manufacturers provide training in how to install their specific pre-manufactured components that make up a metal roof system. In general, there are panels, clips, and termination components (ridge, rake, gutter/eave, curbs, etc.). These components have been developed over decades of trial and error and, when installed correctly, will create a leak-proof roof system which will last as long as any of the other building components. In addition to the metal roof manufacturers, the Metal Buildings and Erectors Association (MBCEA) is a group that provides independent training on the proper erection of metal buildings, including all components of a metal roof system. 

Engineering. The engineering associated with a metal roof system is the responsibility of the manufacturer per the International Building Code (IBC). Local engineering for a particular metal roof can be provided by a professional engineer licensed in the locale of the particular job site. Both sources are readily available to the contractor that wishes to enter the metal roof contracting business. The contractor should not have any concerns about this aspect of a metal roof if he does his due diligence and partners with a manufacturer that will provide the tested engineering characteristics of a particular roofing system and a local engineer who can take that information and perform a code-required analysis. 

Details. As opposed to sheet membrane or shingled roof systems, the metal roof system has its own details. These details require a different understanding of water protection. Metal components, including the actual roof sheet, will not allow water to penetrate and, if protected with a galvalume coating, will last well over 60 years (refer to Metalconstruction.org, Technical Resources, “Service Life Assessment of Low-Slope Unpainted 55% Al-Zn Alloy Coated Steel Standing Seam Metal Roof Systems”).  

These metal components, however, need to be joined and terminated with sealants and fasteners to create a total water-resisting barrier. Again, the panel manufacturers have time-tested details to assist contractors. A word of caution, however: Make sure that you properly select the panel type (standing seam, corrugated panel, snap seam panel, etc.) that best suits the project, and match those selections with a manufacturer and the detail that will perform best. Finally, the local engineer must be used to ensure the detailing will resist the local design loads. The contractor is only responsible to select that qualified manufacturer and engineer—not become one. 

Cost. “Since metal roofs cost a lot more than conventional roofs, they must be hard to sell.” While this statement is prevalent in the metal roofing market, it is blatantly untrue. While the initial cost may be higher than a conventional roof, a metal roof offers an exceptional value over its lifetime. In fewer than 20 years, the cost of a metal roof system can be as much as 50 percent less than that of many conventional roofs, and conservatively one-third the cost of these roofs over a 60-year time frame. End of argument!  

The Retrofit Segment

What about metal retrofit roofing? While that question might scare you more than merely considering entering the overall metal roofing market, it can definitely expand your horizon and offers more potential than just riding a bicycle. If you’ve ever ridden in a car, you know that the experience, comfort and potential for getting places is greatly enhanced. The same concept applies when expanding your metal roof market possibilities to include the lucrative metal retrofit roofing market. This market, with its extremely limited contractor participation and increasing customer demand, makes it very interesting to consider.  

Metal Roof Consultants Inc.

Photo: Metal Roof Consultants Inc.

A recent metal retrofit roofing package of six roofs totaling more than $20 million bid in North Carolina, and only three companies submitted bids. Each contractor ended up with two projects each, totaling between $6 and $9 million per contractor. During this same time, single-ply and shingle projects in the same geographical area attracted many more contractors. Again, you may feel that all-too-familiar twinge in your stomach caused by only looking at the negative consequences you might encounter. However, doing nothing is the worst thing you can do. It is true that finding manufacturers and engineers to assist you when entering the retrofit market can be difficult, as the pool is much more limited than that of the metal roofing industry in general, but these resources are available to you. Just be diligent and look harder!  

Finally, consider what a very wise man said many years ago to a young man just out of college. He said, “Can’t never did anything.” That wise man was my father, and he spoke those words on my college graduation day. My experience has seen the metal roof market develop with many new innovations. The metal retrofit roofing market was not even in existence in the 1970s, but it has since become a market that grows year after year. I have been lucky enough to see, and be part of, a revolution in the roofing industry with respect to metal roofing’s place. All the tools you need to enter the market are out there, but, like that bicycle many years ago, you must first determine why you want to ride it and be willing to risk falling off a few times. The rewards are worth it, even if you get your knees scraped a few times. 

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.

Pages: 1 2

Tips for Reducing Insulation Labor Time and Costs on Commercial Jobs

Composite products can help simplify insulation installation on high-traffic roofs.

Composite products can help simplify insulation installation on high-traffic roofs.

It’s no secret that the roofing industry continues to suffer a severe shortage of skilled labor, resulting in lost business and profits. Former National Roofing Contractors Association (NRCA) chairman of the board Nelson Braddy Jr. was quoted in the Wall Street Journal last fall saying his Texas roofing company had to decline $20 million in projects over the past two years due to worker shortages. “It’s the worst I’ve seen in my career,” he said.

While there is no silver bullet to fix this problem, using materials and methods that simplify installation can help you maximize the people you do have, and potentially even reduce material costs. It’s a win-win for improving profitability.

This article highlights some simple-to-use options for streamlining insulation work on re-roofing jobs and new construction.

Measuring What Matters

When it comes to insulation, roofers can choose from several commonly used rigid foam insulations: polyisocyanurate (polyiso), extruded polystyrene (XPS), and expanded polystyrene (EPS).

The first step in reducing insulation costs is to consider which metric matters most to your bottom line. As the job of insulation is to reduce heat loss through the roof assembly, many manufacturers promote their products’ R-value per inch of thickness. Although this can be helpful if the goal is to build the thinnest roof assembly possible, it says nothing about the material’s benefit vs. cost. To figure out which insulation products will give you the biggest bang for your buck, it is important to evaluate the R-value per dollar.

Figure 1

Figure 1. R-Value per dollar for common types of insulation, including materials and labor.

The table in Figure 1 compares how rigid foam insulations stack-up for R-value per dollar. While specific R-value per dollar figures change frequently, EPS consistently rates highest when compared to other rigid foam insulations.

Easy, Economical Insulation Solutions

For roofing pros who select EPS insulations for their benefit/cost advantages, along with outstanding moisture performance and stable long-term R-values, following are five practical ways to help save tens of thousands of dollars, or more, depending on your job’s size.

1. Build-up of low-sloped roofs. Converting a flat or low-sloped roof to a greater slope for better drainage typically requires roof crews to stack multiple layers of insulation. This can be a labor-intensive process with XPS and polyiso, as crews must haul and place numerous rigid foam sheets of only a few inches of thickness. By comparison, EPS insulation is available in blocks up to 40 inches thick. As some manufacturers will cut those blocks to virtually any slope and any shape to fit roof crickets, saddles, valleys and ridges, tapered EPS speeds insulation installation, and can reduce roof insulation costs up to 30 percent compared to other tapered insulations. The saved man-hours can be deployed to other jobs to help you build your business. Additional cost savings result from reduced dumpster fees to dispose of insulation cut-offs.

2. Roof re-covers. An easy-to-use option for roof re-covers is EPS panels pre-folded into bundles, and with polymeric facers on both sides. Such products are available in standard sizes up to 200 square feet, comprised of 25 panels that are 2 feet by 4 feet each. A typical two-square bundle weighs less than 11 pounds, so is easy for one person to carry.

Fan-folded bundles of EPS require fewer fasteners per square foot than most roofing insulations, and are less expensive than virtually every re-cover board. The man-hours needed to install fan-fold bundles are about 60 percent less than individual sheets. Material costs are also lower than wood fiber, perlite, or gypsum board. On large projects, the total savings can add up to tens of thousands of dollars.

Flute fill insulation helps reduce labor costs on re-covers of standing seam metal roofs.

Flute fill insulation helps reduce labor costs on re-covers of standing seam metal roofs.

3. Metal roof re-covers. Up to 70 percent of metal roofing jobs involve standing seams. Both architectural and structural standing seams make it challenging to create a flat, stable surface during roof re-covers. A simple way to insulate the roof and provide an even surface for other parts of the roof assembly is to install “flute fill” insulation. Such products fit between the spaces of the metal roof’s flanges and are designed to fit into place easily.

An advantage of EPS flute fill over other insulations is that it can be custom-cut to fit any metal roof flange profile. It also comes in a range of compressive strengths suitable for nearly any roofing application. EPS flute fill can save up to 25 percent in costs compared to similar polyiso products.

4. High-traffic roofs. For roofs that need additional strength to withstand foot traffic and severe weather, an ideal option is composite insulation. One product incorporates EPS as a lightweight, insulating and resilient insulation, while a polyiso layer serves as a durable, insulating cover board. Some composite products of this type carry a UL Class A fire rating for both combustible and non-combustible decks, and are compatible with a range of roofing membranes, including EPDM, TPO, PVC, CSPE, as well as low-sloped, built-up and modified bitumen membrane systems.

The Facebook headquarters garden roof uses EPS geofoam as a lightweight fill material to form landscape contours.

The Facebook headquarters garden roof uses EPS geofoam as a lightweight fill material to form landscape contours.

5. Planted roofs. For planted roofs that include landscape contours for hills and valleys, roofers face the challenge of not adding excess weight while defending against moisture intrusion. An effective solution is provided by EPS geofoam. Successfully used in civil engineering and building projects for decades, the material is an ultra-lightweight engineered fill that can be used to create contoured landscape features such as hills and valleys. EPS geofoam weighs from 1 to 3 pounds per cubic foot, depending on the product type specified, compared to 110 to 120 pounds per cubic foot for soil.

And, as EPS geofoam dries quickly and has minimal long-term moisture retention, it helps defend planted roofs from moisture intrusion.

The project team for Facebook’s MPK 20 building in Menlo Park, California, used EPS geofoam in the building’s 9-acre landscaped roof. Landscape contours, more than 400 trees and a half-mile walking trail create a relaxing, park-like setting.

Selecting an Insulation Supplier

Many domestic and foreign companies manufacture EPS insulation, but quality and capabilities can vary widely. To help streamline your insulation material and labor costs further, while ensuring a quality roofing job, it is important to evaluate manufacturers for the following:

  • Technical support: What support services does the manufacturer offer that can reduce roofing contractor costs? Examples include design expertise, material take-offs, consultation on product substitutions, and in-field support.
  • Customized products: Can the manufacturer supply custom-cut insulation components to help reduce field labor?
  • Code compliance: Does the manufacturer have code acceptance reports for its products, including testing to industry standards?
  • Photos courtesy of Insulfoam.

    The Benefits of Above-sheathing Ventilation

    We know proper ventilation of the attic space is an important part of construction. But what is “above-sheathing ventilation”?

    Most roofing materials lay directly on the sheathing. Heat from solar radiation and interior heat loss from the conditioned space are easily transferred through the deck and roof system. This can increase energy costs and cause ice damming. The build-up of heat and extreme temperatures wings can also reduce the life of underlayment and other system components.

    Tile roofs have an air space between installed roof tiles and the roof sheathing. This space reduces heat transfer and allows heat buildup to dissipate from the sheathing and roofing materials. This above-sheathing ventilation, or ASV, inherent to tile roof installations can be enhanced using counter battens, shims or manufactured systems to raise the horizontal battens above the roof deck. The system design will vary with the environmental challenge and goals. Specific examples are described below.

    The Elevated Batten System by Boral Roofing uses treated 1 by 2s with high-grade plastic pads, a vented eave riser flashing and vented weather blocking at the ridge. With these components in place, heat transfer is minimized and heat buildup is dissipated, which reduces energy costs.

    The Elevated Batten System by Boral Roofing uses treated 1 by 2s with high-grade plastic pads, a vented eave riser flashing and vented weather blocking at the ridge. With these components in place, heat transfer is minimized and heat buildup is dissipated, which reduces energy costs.

    Energy Conservation in Hot Climates

    In hot and dry climates, the natural ASV and thermal mass of the tile provide a layer of insulation when exterior daytime temperatures are greater than the conditioned space in the home. Vertical counter battens or shims that raise the horizontal battens increase this space and the corresponding benefit. The addition of vented eave riser flashing and ridge ventilation completes an energy-saving ASV system. The system shown below is the Elevated Batten System made by Boral Roofing, which uses treated 1 by 2s with high-grade plastic pads, a vented eave riser flashing and vented weather blocking at the ridge. With these components in place, heat transfer is minimized and heat buildup is dissipated, which reduces energy costs. The upgraded ASV reduces temperature extremes that shorten the life of the underlayment and other roofing components. These benefits are achieved with no mechanical or moving parts.

    Cool and Humid Climates

    The same installation can provide a different benefit in cool and humid regions. The Tile Roofing Institute and Western States Roofing Contractors Association’s Concrete and Clay Tile Installation Manual for Moderate Climate Regions says that in areas designated “Cool/Humid” zones, “Batten systems that provide drainage/air-flow (shims, counter battens or other approved systems) are required.” The area designated “Cool/Humid” in the current manual runs from approximately Eureka, Calif., to the Pacific Northwest, west of the Cascade Mountains. In this climate, moisture-laden air can migrate under the tile and condense in the space between the tile and roof deck. The underlayment is there to protect the sheathing but if the battens are raised above the deck, condensation will be reduced. Raised battens also allow moisture under the tile to escape to the eave. When roof tiles are fastened to a raised batten, underlayment penetrations are minimized.

    Cold and Snowy Regions

    Ice dams are one of the most damaging phenomena roofing contractors face. Snow movement on roof surfaces can cause damage to people and property. The goal in cold and snowy environments is to prevent ice dams by enhancing the ASV under the tile roof. Typically, a more substantial air space is created using larger vertical battens. A well-designed “cold roof” system that includes proper snow retention is the solution.

    The TRI/WSRCA Concrete and Clay Tile Installation Manual for Moderate Climate Regions refers installers to the TRI/WSRCA Concrete and Clay Roof Tile Design Criteria Installation Manual for Cold and Snow. Regions “in locations where the January mean temperature is 25 deg. F or less or where ice damming often occurs”.

    For more information and to download the Tile Roofing Institute’s installation manuals, visit the Tile Roofing Institute at TileRoofing.org.

    ILLUSTRATION: Boral Roofing

    Planning for Thermal Movement: An Essential Element of Copper Roofing Design

    For centuries, copper has been used as a roofing material because of its ease of installation, adaptability to simple and unique designs, resistance to the elements and superior longevity. Copper’s warmth and beauty complements any style of building, from Gothic cathedrals to the most modern museums and private residences. Its naturally weathering surface, whether in a rich bronze tone or an elegant green patina, is a clear indication that the building owner will only accept the very best.

    This detail indicates a method for terminating a copper roof at the eave. The fascia trim is bent to extend onto the roof deck to become an integral flashing apron nailed to the roof. The copper pan is secured to the apron lip to achieve vertical restraint. Horizontal movement of the copper roof sheet is accommodated by the loose-lock fold of the pan over the fascia lip. Click to view a larger version. IMAGE: <em>COPPER IN ARCHITECTURE–DESIGN HANDBOOK</em>

    This detail indicates a method for terminating a copper roof at the eave. The fascia trim is bent to extend onto the roof deck to become an integral flashing apron nailed to the roof. The copper pan is secured to the apron lip to achieve vertical restraint. Horizontal movement of the copper roof sheet is accommodated by the loose-lock fold of the pan over the fascia lip. Click to view a larger version.
    IMAGE: COPPER IN ARCHITECTURE–DESIGN HANDBOOK

    Unfortunately, long-term performance of even the best construction materials can be compromised if the system is not designed or installed properly. For architectural sheet-metal installations, movement that occurs with changes in temperature must be considered during the design process. All metals expand when heated and contract when cooled. While this process is well understood, far too many contractors ignore thermal movement during system design or installation. Ultimately, this can lead to failure of the roofing and flashing system, causing extreme damage to the building. The Copper in Architecture–Design Handbook, which is published by the Copper Development Association (CDA) and available online as a free download, provides examples of how to accommodate for thermal movement of copper systems.

    Calculating for the potential thermal movement of sheet metal is easy. Simply multiply a metal’s coefficient of thermal expansion by the metal’s expected temperature change by the length of the piece. Remember: It’s not the air temperature we’re considering; it’s the temperature of the metal. Anyone who’s touched a metal roof or the top of their car in the summer knows it gets significantly hotter than the air!

    An example based on a 10-footlong piece of copper:

    • 10 feet (typical flashing piece length) x 0.0000098 per degree F (copper’s coefficient of thermal expansion) x 200 degrees F (possible metal temperature change from coldest winter night to hottest summer day) x 12 inches per foot = 0.24 inch. In this case, the calculated movement is a little less than 1/4 inch.

    Remember, the coefficient of thermal expansion depends on the type of metal you are using. Aluminum expands and contracts more than copper, and most steels move less. Series 300 alloy stainless steels are very similar to copper in movement, or expansion/ contraction rate. Naturally, temperature change is dependent on building location and exposure to the elements. Many professionals feel comfortable calculating the design movement with a temperature change in the 175 to 200 degree F range, but it’s the project architect or engineer’s responsibility to determine if this is adequate.

    Modern rollforming equipment allows contractors and manufacturers to make very long panels, so potential total movement is even more significant.

    Let’s investigate one type of common flashing design—in this case, at the eave, which is relatively simple but can easily be installed incorrectly:

    • Based on the previous formula, with roof panels that are 20-feet long and installed at a temperature between the hottest day and coldest night: 20 feet x 0.0000098 per degree F x 200 degrees F x 12 inches per foot = 0.47 inch.

    Having one of the largest copper roofs in the country, the historic Kingswood High School, Cranford, Mich., recently underwent a massive $14 million roof-restoration project. The copper-clad roof is comprised of batten seams on the upper slopes, interior gutter with internal rainwater conductors, and standing- and flat-seam panels on the eaves. An embossed copper fascia and copper soffit panels complete the system. PHOTO: QUINN EVANS ARCHITECTS

    Having one of the largest copper roofs in the country, the historic Kingswood High School, Cranford, Mich., recently underwent a massive $14 million roof-restoration project. The copper-clad roof is comprised of batten seams on the upper slopes, interior gutter with internal rainwater conductors, and standing- and flat-seam panels on the eaves. An embossed
    copper fascia and copper soffit panels complete the system.
    PHOTO: QUINN EVANS ARCHITECTS

    Because we’re installing mid-way in the temperature range and 0.47 inch is so close to 1/2 inch, dimension “A” can be 1/4 inch (one half the total potential movement). Naturally, the hem of the roof panel’s “loose lock” must coordinate with the length of the eave flashing to ensure the two are still engaged when the roof panels are fully expanded. While most contractors form eave flashings properly, some ignore the thermal movement gap “A” during installation, forcing panels to move fully onto the flashing. This eliminates the gap. When temperatures drop, the panels can’t contract, adding stress to the roofing system.

    Through the years, countless thermal cycles and resulting stresses caused by expansion and contraction can take their toll. In the long run, something will fail. In some cases, work hardening of the metal can occur, causing it to crack or tear. In other cases, fasteners, such as those used to attach cleats, work back and forth, ultimately pulling them out of the substrate.

    It’s easy, however, to avoid these problems. To ensure maximum performance of the roofing system, just follow the recommended design principles; understand how the different pieces of the system interact; and don’t cut corners. With a time-proven quality material like copper, proper workmanship and attention to detail can create a beautiful roof that could last the life of the building.

    Learn More
    For more information about architectural copper and roofing systems, visit the Copper Development Association’s website.

    Tile Roofing: Closed Valleys with Low-profile Tile

    Batten extensions are installed on standard tile W valley metal.

    Photo 1: Batten extensions are installed on standard tile W valley metal.

    A common failure point on steep-slope roof systems is at valleys. Often, aging material, improper fastening, lack of maintenance and ice dams make valleys vulnerable. A common cause of valley troubles with tile roofing occurs when flat tiles are used in areas where closed valleys are preferred and a simple installation requirement is missed.

    The Tile Roof Institute (TRI) Concrete and Clay Tile Installation Manual for Moderate Climate Regions allows for open (flashing exposed) and closed (tiles meet over flashing) valley installations. Installers develop a preference based on their experience with the local climate. Contractors also consider job-specific environmental conditions, aesthetic preferences, pitch and maintenance needs when choosing from valley-installation options.

    Although there are a wide variety of flashing and installation options for valleys, one important requirement is often overlooked and can cause leaks with low-profile tile. The specification is listed on pages 48 and 49 of the installation manual: “When a flat profiled tile is installed as a ‘closed valley’, a ribbed valley metal or single crown valley metal with batten extension shall be used.”

    Batten extensions are installed on standard tile W valley metal.

    Click to view larger.

    Unobstructed water flow in the valley flashing is critical. A flat tile installed directly onto standard valley flashing in a closed method restricts water in the valley flashing during heavy rains and may cause it to overflow. This can speed degradation of the underlayment and may cause rot in the battens and decking. A closed-valley installation can be repaired by replacing the standard tile valley flashing with the correct ribbed metal or by adding a batten extension to each row (see photo 1).

    Because medium- and high-profile tiles have a natural cavity between the flashing and tile, this requirement only applies to low-profile tile. According to the TRI installation manual, the definition of a low-profile tile is, “Tiles, such as flat tile, that have a top surface rise of 1/2 inch or less.” Most tiles with a wood grain, lined or brushed surface still fall into the low-profile category and will require batten extensions or ribbed valley flashing.

    An elevated batten system with ribbed valley flashing.

    Photo 2: An elevated batten system with ribbed valley flashing. PHOTO: Boral Industries

    When using a counter-batten system, or raised batten, the battens themselves can be extended into the valley because they are elevated on a pad or shim. In photo 2, a ribbed valley flashing and an elevated batten are used. Fasteners are not installed in/through the valley flashing.

    Tile installers are craftsmen and each develops his or her own approach to valley details. Depending on the length of the valley and the tributary area, installers may flare or gradually open the width of the valley tile cut. Experienced installers may make a cut (dog ear) to the point of the tile that is overlapped by the succeeding row. Before accessory products, like ribbed valleys and batten extensions, were commercially available and before manufacturers improved the lug design, installers often removed lugs with their hammers. They developed propping and gluing skills to avoid creating a dam with their installation. Now the accessories and flashing designs make this type of installation better and easier.

    Despite the variety of tiles within the low-profile category—some are flat on the back side and fastened directly to the deck, some have lugs on the back that can also utilize battens for attachment— all low-profile tile installed in a closed-valley method requires ribbed flashing or batten extensions unless precluded by manufacturer design and/or approved by the local building inspector.

    An elevated batten system with ribbed valley flashing.

    Click to view larger.

    Because of Florida’s wind and weather extremes, TRI and the Florida Roofing, Sheet Metal and Air Conditioning Contractors Association collaborated on Florida High Wind Concrete and Clay Roof Tile Installation Manual, which also is available on TRI’s website.

    PHOTOS: TILE ROOFING INSTITUTE, unless otherwise noted

    Seal of Approval: How to Make the Most of Asphalt-shingle Sealants

    Extreme weather events, such as the wide temperature swings during the recent winter and hurricanes that afflict coastal regions, have increased consumer demand for reliable and high-performance roofs. Asphalt-shingle roofs have been proven to provide the protection homeowners need, thanks to the material’s durability and longevity.

    Many asphalt shingles rely on built-in sealants to provide a solid installation. This sealant material is an asphalt-based, heat-activated, viscous bonding material, which retains adhesion in difficult weather conditions, after the initial bonding of the shingles has occurred. The sealant will fuse the asphalt shingles together when each course is properly attached to the roof deck and previous courses.

    IMAGE: Asphalt Roofing Manufacturers Association

    Click to view a larger version of this image. IMAGE: Asphalt Roofing Manufacturers Association

    The bonding sealant is factory-applied on the front or back side of the shingle, depending on the manufacturer’s design. Heat from the sun activates and softens the sealant, initiating the bonding process. After the bonding of the shingle sealant, the shingles provide a home with superior wind-resistance.

    If not installed correctly, the sealant will not be able to do its job, which could result in shingle blow-offs and other performance issues. For the roofer, shingles that are not properly installed and allowed to bond could mean an unwanted call back to the job site. The Asphalt Roofing Manufacturers Association (ARMA) recommends contractors follow these essential steps to ensure asphalt shingles are installed properly the first time and that sealant adhesion is not impeded:

    Scheduling: If an asphalt-shingle installation takes place in cold or windy weather, it could impact the ability of the sealant to cure. The sealant cannot bond in cold weather, and the wind could shift the shingles and break the bond before it has a chance to complete the process. Follow manufacturer instructions for cold-weather installation or plan for projects when weather conditions are more suitable.

    Roof Deck: Making sure the substrate and roof deck are not damaged or deteriorated is key to maximizing the potential of the asphalt-shingle sealant. If these elements are overlooked, the shingles will not have a solid base for fastener attachment, and the sealant between the shingles could be less effective.

    Underlayment: Proper installation of an approved underlayment will provide the appropriate surface for shingle installation and will help manage water. Ice-barrier underlayment materials, compliant with ASTM D 1970, are recommended for use in northern climates where accumulation of snow or ice on the roof is likely. The ice shield provides extra protection from the potential for water damage; this is especially important on reroofs of older homes where the placement or quantity of attic insulation allows heat to flow to the roof.

    Accessories: Roofing accessories, such as flashings at penetrations, valleys and changes in direction of the roof, are essential to making sure the sealant can do its job. Roofers should select approved accessories, whether they are drip edges, ridge vents or other architectural details.

    Nailing: The actual attachment of the asphalt shingles is where a roofer has the most control over the installation process. It is important to make sure shingles are attached to the deck with the proper type, size and quantity of nails, as well as in the precise location required. Make sure the nails are in the right place by driving them in the indicated “nailing zone.” Always ensure nails used in laminated shingles are driven through the double-thickness overlap area.

    Selecting a shingle that meets or exceeds wind-speed requirements in local building codes will help a roof covering withstand windstorms and protect a home. Further, roofers should always follow all building codes and manufacturer installation requirements for shingle applications.

    Asphalt shingles are manufactured to provide homeowners with beautiful, affordable and reliable protection for their homes. It is up to the installer to ensure the sealants can do their job by making sure other facets of the proper installation process are followed.

    Correct Side Lap on a Slate Roof

    I’ve been asked to examine slate roof installations all across the U.S., and one of the most disheartening things I’ve observed is how often incorrect side laps are used. For example, the photo shows a slate roof that was installed less than one year ago and already has more than a dozen leaks. Why? Among one of the most basic problems is the side lap.

    This slate roof was installed less than one year ago and already has more than a dozen leaks. One of the most basic problems is the side lap.

    This slate roof was installed less than one year ago and already has more than a dozen leaks. One of the most basic problems is the side lap. PHOTO: John Chan

    The side-lap detail drawing that appears on this page is from the National Slate Association’s Slate Roofs: Design and Installation Manual, page 86, Detail 5-B. The side lap also is referred to as a side joint, vertical joint, keyway, bond line or rain course. As defined in the glossary of the NSA manual, it’s “the longitudinal joint between two slate shingles”.

    Whenever one is installing a slate roof, it is absolutely imperative the side lap is a minimum of 3 inches. As seen in the detail, if the lap is less than 3 inches, water will flow in between the two slates and leak into the building. When I’m asked to inspect a problematic new slate roof, I find the side and head laps are the problems on a majority of all cases across the country.

    If you’re installing a single-sized slate, such as 20 by 12 inches, the slates should be installed so the joints are exactly split in two; the side laps on the whole roof should be 6 inches. Similarly, if the roof has 10-inch-wide slate, the side laps should be 5 inches. Whatever the width, the side lap should always be one-half the width on a single-sized slate.

    It gets a little trickier on a random-width slate roof. Slate widths can be as narrow as 6 inches or as wide as 20 inches or more. When dealing with 6-inch slates, the joint obviously must be split exactly in the center, so there are 3 inches on each side. If you question the width, pull out a tape measure; this will save you and the building owner lots of money and headaches. When there are inadequate side laps, inevitably, the owner, architect or general contractor gets concerned, and then I get a phone call to do a full roof survey on the slate roof.

    Click to download a larger version of this side-lap detail drawing from the National Slate Association’s <em>Slate Roofs: Design and Installation Manual</em<, page 86, Detail 5-B.

    Click to download a larger version of this side-lap detail drawing from the National Slate Association’s Slate
    Roofs: Design and Installation Manual
    , page 86, Detail 5-B.

    As slaters become more advanced, they are able to eyeball 3 inches extremely well, but until that point, installers should use a tape measure, or they should stick with using single-sized slates. It might seem too easy, but this is one of the most common errors I encounter. If a slater studies Detail 5-B and adheres to it, he or she will avoid having this problem with slate roof installations.

    Too often, slate is given a bad name because of poor installation. Hopefully, this article and detail will resolve that problem.