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.