Enhanced Self-Adhered Membranes Reduce Installation Time and Labor Cost

Polyglass U.S.A., Inc., has enhanced the performance of its self-adhered mod bit roofing membranes. Used to design durable low-slope roof systems, the upgraded membranes install faster and cleaner resulting in labor and time savings, according to the manufacturer.

A pioneer of self-adhered roofing technology, Polyglass manufactures a full line of multi-surface membranes that do not require a torch or hot asphalt during application. With its cutting-edge ADESO Dual Compound Self-Adhered Technology, the company produces membranes with APP or SBS modified asphalt compounds with a top layer acting as the weathering surface and an aggressive self-adhered compound on the bottom layer.

Polyglass recently added a new labor-saving feature, patent-pending SEALLap Ultra, to promote instantaneous watertight side lap seams in all the Self-Adhesive Membranes. SEALLap Ultra is a self-adhered compound applied on the side lap area to increases the bond strength and long-term adhesion of the seams.

Additionally, to reduce installation time, Polyglass developed FASTLap — a granule-free end lap that installs hassle-free. FASTLap is designed to promote watertight end laps and enables easy and safe installs.

“We are proud of the advancements made to the self-adhered products,” said Scott Lelling, director of strategic marketing. “Polyglass continues to invest in technology and discover better ways to roof, passing on savings to the roofing contractor while helping them to meet the needs of their customers.”

LEARN MORE

Visit: www.polyglass.us

Call: (800) 222-9782

Upgraded Flashing Offers Longer UV Protection

TAMKO Building Products LLC offers the newly-upgraded TW-105 Flashing Membrane, which features white polymer surface film technology that gives the product increased UV resistance. According to the manufacturer, this new generation of TW-105 increases the UV resistance from the original 60 days to an extended length of 180 days.

“We’re always looking for ways to provide contractors with the products they need and these improvements offer TAMKO contractors more flexibility in their project timelines,” said Stephen McNally, TAMKO’s Vice President of Sales and Marketing.

TW-105 Flashing is a self-adhering SBS-modified bitumen membrane used for balcony and breezeway details in conjunction with TAMKO’s TW-60 Self-Adhering Waterproofing Membrane, TWM-1 Mastic, and either TWP-1 Adhesive Primer, TWP-2 Water-Based Adhesive Primer or TWP-LV1 Low VOC Adhesive Primer – all part of TAMKO’s waterproofing product line. Additionally, TW-105 Flashing may be installed at wall/floor intersections and other transition locations. 

TW-105 Flashing is available in 12-inch by 40-foot rolls and each carton contains two 40-foot rolls for a total of 80 feet of length per carton. The product comes with a 5-year Limited Warranty and Arbitration Agreement. It is manufactured in Columbus, Kansas, and is available for shipping across the United States. 

For more information, visit www.TAMKOwaterproofing.com.

Lead-Free Roof Flashing Membrane Designed for a Variety of Applications

MFM Building Products, a manufacturer of a full envelope of waterproofing and weather barrier products for the building industry, offers a new innovative roof flashing membrane – GreenWeld PVB. GreenWeld PVB armored flashing system is a high-performance PolyVinyl Butyral (PVB) membrane enhanced with an aluminum scrim for superior flexibility, strength and weathering. The membrane is comprised of recycled PVB and can be used in residential and commercial roofing applications. Typical applications include flashing for pipe penetrations and support beams, water barrier for cavity walls, liner for valleys of shingle, tile and aluminum metal roofs, and through-wall flashings.

GreenWeld PVB is designed as a replacement for lead, sealant pockets or liquid flashing systems. The membrane offers the roofing contractor significant advantages. According to the manufacturer, it is easy to cut and use, heat-weldable, non-toxic, sustainable, flexible and lightweight, and comes with a 20-year warranty. Independent, third-party testing shows that GreenWeld has the same waterproofing properties of traditional lead used to seal roof penetrations.

GreenWeld PVB is available in roll widths of 10 inches, 20 inches and 39 inches by 19.5-foot-length rolls. Each roll is pre-packaged in a shrink sleeve for protection until use. Some applications require GreenWeld Adhesive/Sealant, which is also available from the company.

For more information including technical data, installation instructions or to request a free product sample, visit www.mfmbp.com.

Fluid-Applied Membranes and Roof Restoration Methods

Cold-process fluid-applied systems combine the elastic properties of rubber polymers with the waterproofing characteristics of a highly refined emulsified asphalt. The result is a monolithic, seamless rubber membrane. Photos: Paragon Roofing Technology

Fluid-applied membrane systems have been available on the U.S. commercial waterproofing market for many years. Originally, the systems most frequently applied were hot-applied emulsions with or without reinforcements. In the early 2000s, a liquid rubber membrane system was developed that could be applied in cold-process fluid-applied applications. The liquid rubber material combines the elastic properties of rubber polymers with the weatherproof/waterproof characteristics of a highly refined emulsified asphalt. The resulting formulations are proprietary materials that, when properly applied, adhere to form a monolithic rubber membrane. The resulting membrane can be applied to range from 20 mils to 200 mils dry.

Unlike coatings that only provide a film surface or adhesives that require reinforcements for waterproofing capacity, the liquid rubber forms a seamless membrane that provides instant  waterproofing/weatherproofing capabilities. The material cures within seconds to 80 percent of its full strength with full cure within 12 hours of application. The liquid rubber membrane is manufactured at the point of application through its dual component formulation; the system consists of a spray grade and a catalyst that are mixed together at the moment of application through specially designed spray rig equipment. The chemical reaction between the spray grade and the catalyst results in an instant, seamless rubber membrane. The instant set allows the seamless membrane to be in direct contact with water immediately. This feature also allows for the material to be applied either horizontally or vertically up to 200 mils thick in one application. Although the membrane still requires time to fully cure, it is approximately 80 percent cured when the two materials come into contact. This is a unique feature of the material, and it requires specialized equipment and training to be applied correctly.

Advantages of Liquid Rubber Membranes

The dual component formulation consists of a spray grade and a catalyst that are mixed together at the moment of application using specially designed spray equipment. Products are also available in one-part emulsions for application with brushes and rollers.

Liquid rubber membranes combine the properties of adhesives and coatings while adding significant technological advancements that create an instant-setting waterproofing/weatherproofing membrane. It is the 21st century version of a built-up roof (BUR) system that has the performance characteristics of modified bitumen and—because it is a monolithic, seamless membrane—it provides a longer service life with less maintenance than other options. Liquid rubber membranes provide economical solutions to almost all roofing and waterproofing/weatherproofing applications and offer excellent performance characteristics.

The primary advantages of the material are as follows:

· Superior elongation and recovery. Structures move. Surfaces expand. Seasonal temperature changes alter the size and shape of every object. Liquid rubber membranes have the capacity to stretch and recover, which allows for movement of the underlying surface. The average elongation is over 1,000 percent, and the material recovers to 90 percent of its original state after elongation.

· Excellent adhesion. Liquid rubber bonds to most substrates and forms a permanent bond with itself, resulting in self-healing and self-sealing properties. The liquid rubber membrane provides excellent adhesion to metal, wood, plastic, and concrete — even green concrete. It also provides strong adhesion to existing construction materials like BUR, modified bitumen, thermosets and thermoplastic membranes, and all waterproofing materials. In most cases, no primer or tack coat is required.

· Sustainable and environmentally responsible. The materials contain no VOCs and satisfy EPA regulations and environmental concerns. No special ventilation is required, as the material is non-toxic, odorless, and non-flammable.

· Safe applications. Products are available that can be applied with trowels or squeegees as well as a specially designed dual-component spray rig. No heat, kettles, torches or open flames are required in the application process. The material is safe to apply and poses no health risks to the applicators.

Another advantage of the liquid-applied system is that the material is self-leveling. This allows the membrane to conform to substrate irregularities and provide a continuous seal at penetrations, which are typically the most difficult details in roofing applications.

Another primary advantage of the liquid rubber membrane system is that the material is self-leveling. This allows the membrane to conform to substrate irregularities and provide a continuous seal at penetrations, which are typically the most difficult details in roofing applications. The instant, full adhesion of the membrane allows for continuous system application without additional components that would be required with other membrane applications. This eliminates the chances of deformation from the breakdown of different material system components. It also eliminates some of the application errors associated with multi-component systems.

Deformations of one of the materials in the multi-component system can lead to failure of the total system. Examples of typical defects in roofing systems include loss of attachment from improper adhesive application at substrate, insulation or membrane; improperly aligned insulation; loss of attachment of insulation due to substrate irregularities; voids in membrane attachment that lead to blisters and/or ridges; and slumping or buckling flashing due to improper attachment. The improper attachment of one component leads to differential movement in the system.

Liquid-applied systems form a monolithic membrane, eliminating the most vulnerable point of rolled membranes for moisture infiltration: the seams. The superior adhesion characteristics to all types of substrates and materials also eliminates the chances of moisture infiltration under the membrane.

While overspray is minimized in liquid rubber membrane applications, precautions should still be set at perimeter building locations and application should not be attempted in high winds.

The elongation and flexibility of liquid rubber membrane exceeds industry standards. This allows it to withstand typical thermal cycling and perform well in extreme heat and cold. Application temperatures are wider than most other adhesives and coatings, and range from ambient outside temperatures of 20 degrees Fahrenheit to over 100 degrees. The membrane is naturally UV resistant and can be exposed throughout the lifetime of the membrane. The membrane is compatible with all types of reflective coatings if application is required. Granule surfacing can also be applied.

The membrane is also very durable. Depending on applied dry mil thickness, the membrane can withstand heavy force and is puncture resistant with self-healing and self-sealing properties.

The membrane can be applied over damp surfaces and it can be exposed to ponded water in unlimited duration. The material has been used as pond liners and in containment tanks since its introduction to the market. The water absorption rate is less than 1 percent—well below ASTM’s minimum water absorption rate of waterproofing materials, which is 5 percent.

Benefits for Applicators

There are significant benefits to applicators of liquid rubber membranes. The foremost benefit is the reduced crew size required for application. This is an important consideration due to the severe labor shortages affecting the construction industry.

In most cases, a crew of three properly trained and experienced applicators using one spray rig can complete up to 10,000 square feet in one day. Additional hoses and/or spray rigs can double or triple those production rates.

In addition to the advancements in material technology, there are vast improvements to the specialized equipment used in the application process. The spray equipment is now portable and can be transported to construction sites without heavy trucks and covered trailers. The spray equipment is also lightweight and can be easily positioned on roof areas or waterproofing trenches. This equipment is housed on four-wheel carts for easy transport throughout the construction site.

The spray equipment consists of a high-volume, low-pressure system. The dual component equipment mixes the two components outside the gun to form a monolithic membrane upon impact with the substrate.

The equipment has a direct drive system to eliminate downtime associated with traditional belt drive systems. The application rate averages up to 1,000 square feet an hour for one gun. The equipment can run two guns at the same time, which increases production to 2,000 square-feet per hour. It can run up to 600 feet of hose and the material can be contained in everything from a 5-gallon pail to a 275-gallon tote. The most common container is a 55-gallon drum.

The spray guns have also improved. Advancements in manufacturing have eliminated most of the clogging issues that plagued spray guns in the past. The spray guns are lightweight and can be disassembled rapidly if material clogs occur. The older spray guns took up to an hour to take apart in the event of material clogs.

Overspray—a common problem with most spray applications—is minimized in liquid rubber membrane applications because it is a low-pressure application and the material cures instantly after release from the spray gun. Precautions, such as coverboards, should still be set at perimeter building locations and application should not be attempted in accelerated wind conditions, but the chances of excessive overspray are minimal.

Liquid Membranes and Roof Restoration

Because of their waterproofing/weatherproofing capacity, instant cure set, adhesion success with most substrates and materials, wide range of application temperatures and membrane mil thickness that can range from 20 mils to 200 mils dry, liquid rubber membranes can perform in most building exterior applications, including new and remedial roofing applications. At this time, the systems are being used primarily as roof restoration and repair products.

Typical roof restoration projects include applications over built-up roof systems (asphalt and coal-tar), thermoplastics, EPDM, sprayed polyurethane foam, metal and tile. The liquid rubber membrane systems were designed to significantly extend the service life of the existing roof system. They are also excellent for repairing flashings and penetrations. The spray equipment is small and mobile and most repairs can be completed with minimal manpower.

When it is applied by knowledgeable installers, the system is an excellent economical choice for building owners. The initial step in the restoration process is the proper repair of the existing roof system and preparation of the surfaces. All surfaces should be free from any loose dust, debris, oil, grease or foreign material. These items should be removed prior to application by means recommended by the manufacturer. The liquid rubber membrane can be applied over damp surfaces; however, extensive ponding water should be removed prior to application.

Proper roof repairs should be completed in compliance with roofing industry standards. The one-part emulsion can be used for repairs to the existing membrane. Reinforcements should be added as required. All cracks, penetrations, existing seams, corners should be addressed using polyester fabric with roller/brush or trowel grade.

Once proper repairs and preparation are completed, the liquid applied membrane can be applied to the existing roof surface. For most roof membranes and substrates, a light rinse/power wash of the surface is all that is required. A primer is required over existing EPDM membranes.

The other exception is on aggregate surfaced built-up roof systems, which require additional preparation. Removal of all loose aggregate is required. On asphalt-based BUR, the liquid applied membrane can be applied directly over the prepared surface. For coal-tar based BUR, a manufacturer-approved fabric is required due to the gassing of the coal tar. The reinforcement should be set in a 20-mil wet profile of one-part liquid rubber. The reinforcement shall be set in a full and even application so that it is fully adhered with no wrinkles, buckles or blisters. The liquid rubber membrane is then set over the reinforcement. For best application practices, the reinforcement should be set in place with a soft-bristle broom.

The application of moisture relief vents is also required on BUR systems to prevent gassing of bitumen, which could contribute to blisters. Typical applications require one vent for every 1,000 square feet. Additional vents may be used in areas with existing moisture in the system.

Once the preparation and proper repairs have been completed, the liquid rubber membrane can be applied. Application can be completed with brush, roller or trowel in smaller application areas. Spray grade material shall be applied using specialized equipment. Apply material in a full and even application. Always apply it in strict accordance with manufacturer’s recommendations and approved submittals.

Stir materials during application in accordance with manufacturer’s instructions to avoid product separation. Applicators should spray the fluid component as a continuous, monolithic and seamless membrane of uniform thickness, beginning at the lowest point and terminating at the highest point. In the event the membrane is applied too thin, contact the manufacturer for recoating guidelines. Prior to application, create a grid across the roof with spray paint, allocating one drum of material per section of the grid. Perform cut-outs to check mil thickness and retain samples. Typically, three test cuts are to be taken per 1,000 square feet. In addition, continuously check wet millage by using the “T” post on a caliper mil gauge. After the liquid rubber membrane has cured, apply trowel adhesive to any visible voids. Comply with the manufacturer’s recommendations for proper membrane terminations.

For horizontal applications, apply the two-part liquid rubber membrane in a single, monolithic coat to minimum 80 mils wet/60 mil dry. Repair damaged installation in accordance with manufacturer’s requirements. The spray application requires a 90-degree spray angle (a golf putting motion) with the spray tip within two feet of the surface. Wider spray angles will decrease mil thickness and can cause uneven application.

Ultraviolet stabilizers are added into the material formulation so the completed liquid applied membrane does not require additional surfacing for UV protection for short term (less than ten years) exposure. Long-term exposure (and warranties) require that some sort of surfacing is applied for additional reflectivity or protection. A variety of surfacing materials, including coatings, granules, pavers and living roof applications can be applied.

Liquid-applied membranes are typically eligible for warranties from 10 to 25 years. Contact the manufacturer for warranty requirements.

About the author: John A. D’Annunzio is the owner of Paragon Roofing Technology, headquartered in Troy, Michigan. He has been involved in testing, evaluating, and designing roofing and waterproofing materials and systems for more than 30 years. For more information, visit www.paragonroofingtech.com.

Electronic Leak Detection Testing System Developed for Black EPDM

Detec Systems has developed the IntegriScan scanning platform. According to the company, this is the only testing method capable of Electronic Leak Detection (ELD) testing of conductive membranes including Black EPDM and semi-conductive waterproofing systems. Black EPDM contains carbon black, which produces a level of electrical conductivity that makes testing impossible using high voltage and vector mapping.  

In order to enable valid ELD testing of Black EPDM, TruGround Conductive Primer must be applied directly below the membrane per ASTM D7877. TruGround can be used for quality assurance testing on newly installed, fully adhered or mechanically attached EPDM membranes. Once applied, ELD testing can be performed for the life of the roof. Future breaches or seam voids can be quickly pinpointed allowing repairs to be done immediately, preventing costly moisture damage to occur. The IntegriScan and TruGround are compatible with all membranes including EPDM, TPO, PVC, modified bitumen, and hot and cold fluid-applied waterproofing.

For more information, visit www.detecsystems.com.

Replacing a Roof Drain on a Structurally Sloped Steel Roof Deck

Figure 1. Roof drain detail. Photos: Hutchinson Design Group Ltd.

What is the number one goal of any building owner when it comes to the roof? They don’t want water pouring through their ceilings damaging the interior of the building. How do you keep water out of the building? By keeping the water on the exterior of the building and directing it to the roof drains or other drain locations, such as scupper or gutters. The roof drain is, on a basic level, one of the simplest details on the roof, and yet it is flashed incorrectly time and time again. This paper will walk you through the process of replacing a roof drain on a structurally sloped steel roof deck and installing the new roof system and flashing.

Photo 1. The sump pan and drain body have been installed. Photos: Hutchinson Design Group Ltd.

First off, we are going to assume that the current drainpipe is adequate to handle the existing water volume and drain its portion of the roof, and that the drain pipe is in good condition. Our new roof system will meet the current R-30 requirements for continuous insulation above the roof deck in a roof near Chicago. So, our roof system will be composed of a mechanically fastened substrate board on the steel roof deck, a self-adhering vapor retarder, two layers of 2.6-inch insulation mechanically fastened, a 1/2-inch modified gypsum cover board set in bead foam adhesive, and fully adhered EPDM membrane. (See Figure 1.) We will also assume that the roofing contractor is acting as the general contractor for our scenario.

Now that we have our parameters out of the way, what’s first? I have never met a building owner that likes construction debris inside of their conference room or classroom, so the interior needs to be protected prior to the removal of the existing roof drain. This can be as simple as some Visqueen, but the interior protection needs to be installed prior to the removal of the existing roof drain. The one question that seems to come up is, who is installing this protection? The owner? The plumber? The roofing contractor? I like to put this on the plumber. He knows when he is removing the drain and installing the new one.

Once the interior protection is installed, we need to coordinate the removal of the existing roof system and installation of the vapor retarder with the removal of the existing roof drain, as well as the installation of the new metal sump pan, drain body and lead and oakum joint to the existing drain pipe. (See Photo 1.) This all needs to be done on the same day so that the roof can drain properly and that the vapor retarder can be terminated onto the roof drain flange. This part is critical, as with experience this designer has learned that the vapor retarder can be used as the seal between the extension ring and the roof drain flange and that the O-ring can be eliminated. The sump needs to be fastened to the roof deck around the perimeter at 8 inches on center and be centered on the drainpipe. The drain body then needs to be set over the drainpipe and lead and oakum installed between the drain body and drain pipe.

Installing the New Roof

So, now we have the roof drain body and the vapor retarder installed. Now comes the new roof system. To meet our R-30 requirements, we are going to need a base layer of 2.6-inch polyisocyanurate insulation and 4-foot-wide, 1/2-inch-per-foot tapered insulation sump around the roof drain. This sump will get us to the R-30 requirements of 4 feet from the roof drain as required by the current codes. If my math is correct, that will leave 3.1 inches of insulation at the roof drain. We will need a reversible collar and threaded extension ring to accommodate this height. When setting the reversible collar onto the drain bowl, set it in water cut-off mastic. If the drain ever becomes clogged, this will help to keep water from seeping under the reversible collar and into the roof system. Next the threaded extension ring is installed. First, install some water cut-off mastic onto the treads prior to engagement with the reversible collar. Once again, this will help to prevent water from entering the roof system if the drain becomes clogged and backs up.

Photo 2. The extension ring has been set lower than the cover board (yellow) and water cut off mastic has been installed on the extension ring flange. Photos: Hutchinson Design Group Ltd.

One of the main questions that I receive from the roofing and plumbing contractors is, “How high should I set the extension ring?” Well, it varies per roof system, but for our scenario it needs to be set flush with the top of the tapered insulation. We set it here because we have our cover board that has yet to be installed, and when the clamping ring is installed it will be lower than the cover board. Now back to the insulation; the 2.6-inch insulation should be installed as close to the extension ring as possible, chamfered as required to fit under the flange. Next the tapered insulation sump is installed. This should be installed as close as possible to the extension ring flange and chamfered as required to fit beneath the flange. All voids between the extension ring and the insulation should be filled with spray polyurethane foam insulation.

Once we have our insulation installed, next comes the cover board. The number one thing with the cover board and roof drain is having the cover board cut perpendicularly to the roof drain flange. (See Photo 2.) Do notchamfer the cover board. Chamfering the cover board may ease the transition of the membrane onto the extension ring flange, but it creates an unsuitable substrate surface for the bonding adhesive. And in my experience, water seems to end up ponding around the roof drain and not dropping into the roof drain. This will also allow the roof’s drain clamping ring to sit flat and below the roof surface of the roof.

Photo 3. The membrane has been correctly cut in a cloverleaf pattern. Photos: Hutchinson Design Group Ltd.

Now that our cover board is installed, we have the membrane and its transition into the roof drain. Water cut-off mastic is to be installed on the extension ring flange. How much you ask? One tube. Load that flange up. Make two thick beads with it. I have never heard a contractor say, “Man, using all of that water cut-off mastic on the job really set me back.” It’s a small item, but it is worth it.

After the membrane has been installed and the clamping ring is set, it’s time to cut a hole in the membrane to allow the water to get to the drain and off the roof. How big should the hole be? As small as possible is what some contractors might say. I ask a question to you now: what is the goal of the roof drain? If you answered to get the water off the roof as quickly as possible, you would be correct. Then why would the contractor want to cut a small hole in the roof membrane that would restrict the flow of water into the roof drain piping and off of the roof? I am dumbfounded as well. When we detail the roof drain, we call for the membrane to be cut back to within a 1/2 inch of the extension ring in a cloverleaf pattern around the clamping ring bolts. (See Photo 3.) This way there is no confusion on how far back the membrane is to be cut. Set the drain dome and the roof drain detail is complete.

So, there you have it. Now the roof can drain properly with a brand-new roof drain with no problem (fingers crossed).

Regular Roof Inspections Help ‘Keep the Door Open’

A roof inspector makes field observations. Photo: Kemper System America Inc.

Regular roof inspections give consultants and contractors a chance to maintain relationships with building owners and managers and create value beyond any immediate repairs.

Commercial roofs should be inspected at least twice a year, typically in the spring and fall. Roof inspections are also advised after major weather events, though contractors may already be deluged with repair requests. Of course, building managers will be more receptive to discussing regular inspections during such times, even though time is short. A service flyer and readily available letter-of-agreement can help quickly close the deal, and be used after any major job throughout the year to create recurring business. Customers should clearly understand the service offer and any special provisions for emergency repairs or exceptions such as during wider emergencies.

Common Sources of Roof Leaks

  • Cracks in or around flashings and penetrations
  • Breaks in and around gutterways and drains
  • Poor drainage or debris-clogged drainage systems
  • Storm damage, tree branches, ice dams, etc.
  • Incidental damage by other trades during construction or maintenance
  • Excessive foot traffic at rooftop access points and around HVAC units and other rooftop infrastructure
  • Old or deteriorating roofing materials

While roof leaks can be caused in several ways, many common sources of leaks can be prevented with liquid-applied coating and membrane systems that fully adhere to substrates and are both self-terminating and self-flashing. Membrane systems are fully reinforced and create a seamless surface. High-quality systems are designed to withstand ponding water, ice, snow, UV light, as well as most chemicals. Unreinforced roof coatings can be used for repairs or complete restoration of the roof surface.

If only a small area is damaged, a limited repair is best, and usually possible with compatible materials over an existing system in good condition.Check if a warranty is in place, and if possible contact the manufacturer before the repair. Perform any repairs within the guidelines of the warranty.

For wider areas, a roof recovery is often possible right over the existing roofing. If interior leaks from a field area are evident, core samples can verify the condition of the existing roof assembly down to the deck. Built-up roofs (BUR), in particular, are susceptible to sun and temperature cycling. Tiny spider cracks and micropores can develop in the surface, and the layers below can absorb moisture and deteriorate. Water always travels to its lowest point and, if left unchecked, will damage the underlying structure.

On low-slope roofs, areas of ponding water are a prime target for inspections. If the roof is covered by aggregate or overburden, it must be cleared from around the lowest point of any low-lying areas, and other areas of suspected damage. A visual inspection can locate the source of an active leak, but there may be more than one source or a larger issue that may not always be visible. Broader sampling is needed to evaluate the general condition of the roof and the scope of any deterioration.

Quality workmanship and materials help avoid callbacks and ensure long-term relationships. After completing any necessary repairs, a PMMA, polyurethane or elastomeric membrane or coatings system can be installed to extend the service life of an existing roof. Elastomeric-based coatings are generally the best value for straightforward repairs and can be ideal for recovering metal roofs. Roof restoration, in general, can enhance building performance with “Cool Roof” products, especially those with a high solar reflectance index (SRI).

At the end of the day, an ounce of prevention and a prompt response to issues can help building owners avoid expensive headaches. People remember expert advice and quality service, especially in times of need. They also may tell others — which is another way regular inspections can help keep the door open to recurring business.

Contractor Conquers Tough Weather, Tight Schedule

The roof on the new Goodman Logistics Center (the building on the right) encompasses more than 1 million square feet. The roof system installation met an aggressive timeline that spanned the winter months. Photo: Goodman Carlisle LLC

Goodman, an international commercial and industrial property group, approached Donald B. Smith Inc. of DBS Roofing in November 2017 to support the roofing of the company’s new Logistics Center in central Pennsylvania.

Founded in 1948, DBS Roofing is a second-generation, privately held company whose principles of quality and workmanship have earned the team countless awards. Among those honors include the Firestone Master Contractor recognition, the Baltimore Builder’s Exchange “Craftsman of the Year Award” and numerous industry publication recognitions for notable projects.

The Logistics Center roof was 1,010,000 square feet and was established on a very aggressive timeline that spanned through the tough Northeast winter months. The initial specifications of the job called for a mechanically fastened TPO roof system, which was going to be challenging with the size and timeline of the project. Additionally, the condensation levels in central Pennsylvania are not ideal for mechanically fastened solutions, as it would require applying a vapor barrier and foam around all perimeters, exceeding the original budget and schedule.

To save time and keep the project moving forward during the unfavorable winter conditions, DBS Roofing elected to use one of the company’s favorite “box world” solutions — Firestone Building Products (FSBP) UltraPly TPO SA with Secure Bond Technology.

Photo: Goodman Carlisle LLC

The TPO roofing system is comprised of a self-adhering membrane with factory applied, pressure sensitive adhesive and technology designed to ensure uniform adhesion coverage across the entire membrane. According to the manufacturer, the system can be installed in weather as cold as 20 degrees Fahrenheit.

“Commercial roofing in central Pennsylvania can be very challenging during the winter season, but Firestone UltraPly TPO SA allows our business to continue working through those conditions and prosper,” says Donnie Sanders, president of construction, DBS Roofing. “Being able to apply the Firestone TPO SA at 20 degrees resulted in a successful year for us.”

The Goodman Logistics Center roofing project began on November 1, 2017 and was completed on time March 1, 2018.

TEAM

Roofing Contractor: Donald B. Smith Roofing Inc., Hanover, Pennsylvania, www.dbsroofing.com
General Contractor: ARCO Design/Build Northeast, King Of Prussia, Pennsylvania, http://arcodbi.com

MATERIALS

Membrane: UltraPly TPO SA with Secure Bond Technology, Firestone Building Products, www.firestonebpco.com
Insulation: 2.5-inch ISO, Firestone Building Products

Commercial Roofing Contractor Flexes Its Muscles on 1.3 Million-Square-Foot Project

The new Under Armour distribution warehouse roof encompasses 1,286,000 square feet. It was topped with a TPO roof system manufactured by Johns Manville. Photo: Orndorff & Spaid Roofing Inc.

Industrial projects exceeding one million square feet of roofing might give some contractors pause, but at Orndorff & Spaid Roofing Inc., it’s just another day at the office.

The third-generation family run roofing contractor has been in business since 1953. Orndorff & Spaid services the Baltimore-Washington metro area, as well as parts of Virginia, Pennsylvania, and Delaware. It focuses primarily on large-scale commercial projects, including warehouses, distribution centers, retail businesses, schools and data centers.

Orndorff & Spaid routinely tackles roofing projects up to 1.5 million square feet. The company strives to keep as much work as possible under its own control, and the necessary supplies and equipment are always on hand at its 13-acre headquarters in Beltsville, Maryland.

“We’re a little bit unique as a roofing company in that we self-perform almost everything,” says Richard Harville, vice president of estimating. “We have our own cranes, all our own lifts. We do our own trucking. We have an in-house mechanic’s shop that repairs all of the equipment. All fuel servicing is done from our yard here. We also warehouse a fair share of material here because the logistics of running a job.”

Photo: Johns Manville

A recent new construction project at the former location of a Bethlehem Steel factory in Tradepoint St. John’s was right up their alley. “This was a new construction project, fairly conventional in most regards except for one, and that had to do with the site,” notes Harville. “Most of the site had been infilled over the years, and there was a lot of slag and other materials on this site, so it is not bedrock, for sure.” Due to the potential for movement, seismic expansion joints were specified. The gaps in the deck were as wide as 9 inches.

The owner of the complex was kept under wraps during construction phase, but the completed Under Armour distribution warehouse is now an area landmark. The roof encompasses 1,286,000 square feet, and the project had to be completed under a very tight schedule.

The general contractor on the project, FCL, reached out to Orndorff & Spaid during the design phase, and they recommended a TPO roof system manufactured by Johns Manville.

Harville shared his insights on the project with Roofing, along with members of the project team including Dane Grudzien, estimator; Carl Spraker, project manager, single ply; and Mike McKinney, project manager, sheet metal.

The Clock Is Ticking

Work began in April 2017 with a deadline to finish by the end of July. “The schedule was what made this project difficult,” notes Harville. “They had an end user set to come in and they were in an extreme hurry to get this thing done.”

Workers outside the safety perimeter were tied off 100 percent of the time using AES Raptor TriRex Safety Carts. Photo: Orndorff & Spaid Roofing Inc.

Harville and Spraker were confident the experienced team would be up to the task. “Once we got our bearings, we rock and rolled this job,” Spraker says. “We had up to 40 employees on the site and worked six days a week.”

The roof system installed over the structure’s metal deck included two layers of 2.5-inch polyiso and a 60-mil TPO membrane. “This job was mechanically attached at 6 inches on center, with perimeter and corner enhancements as required by FM,” notes Grudzien.

The roof installation began with a 10-man crew, and crews were added as the work ramped up. “We ended up with four 10-man crews, with the foreman on the first crew in charge the team,” Spraker recalls. “We just did as much as we could every day and kept track of everything. We averaged 700 squares a day. One day we did 1,000 squares.”

Crews worked on half of the building at a time, with falling back as needed to install flashings or strip in the gravel stop. “We started on one side of the building and went from end to end, following the steel contractor,” says Spraker. “When we finished one side, we came all the way back to the end where they started and followed them down the opposite side.”

The roof system incorporates 276 VELUX skylights that provide daylighting in key areas of the facility. Photo: Orndorff & Spaid Roofing Inc.

The roof also incorporated 276 VELUX skylights to illuminate key areas of the facility. Logistics Lighting delivered them all in one shipment, as Orndorff & Spaid requested. The 4-foot-by-8-foot skylights were stored on site and loaded to the roof with a crane for installation after a plasma cutter was used to cut holes in the deck. Prefabricated curbs were installed and flashed. “I had a separate crew designated just to install skylights,” Spraker notes

Safety precautions included perimeter warning lines, and workers outside that area were tied off 100 percent of the time, as they were when the skylights were installed. AES Raptor TriRex Safety Carts were used as anchor points.

Safety is always crucial, notes Harville, and the company makes it a priority on every project. “Our safety parameters go above and beyond standard state or federal mandating,” he notes.

Metal Work

The scope of work included large external gutters, downspouts and edge metal. According to McKinney, the sheet metal application was pretty straightforward. “There was just a lot of it — long, straight runs down two sides,” he says. “The coping was installed on the parapets on the shorter ends.”

Gutters were installed after the roof system was in place. “The roof wasn’t 100 percent complete, but once areas of the roof were installed and the walls were painted white, we could begin to install the gutters,” says McKinney. “After work was completed on one side, crews moved to the other side.”

The large gutter featured internal and external hangers, alternating 36 inches on center. All the metal was fabricated in house, and the exterior hangers were powder coated to match the steel.

Once the external hangers were installed, the gutter sections were lowered into place and secured by crew members in a man lift. “Once you had your hangers up, you could just lower the gutter over the side and into the external hangers,” McKinney explains. “We put the internal hangers into place after that. After the drip edge is installed, the single-ply crews come back and flash the drip edge into the roof system.”

Downspouts were custom-designed to match the building’s paint scheme. Photo: Orndorff & Spaid Roofing Inc.

Installation of the downspouts had to wait until the walls were painted. One wrinkle was the change in color of the downspouts. About two-thirds of the way up the wall, the paint scheme went from black to white, and the building owner wanted the downspouts to change colors to match. “We reverse-engineered it,” notes McKinney. “We measured from the paint line up and put in a 30-foot section of downspouts there, because we put our bands at the joints and we didn’t want to have the bands too close together in the middle of the wall.”

Talented Team

The project was completed on budget — and a month early. FCL hosted a barbecue to celebrate. “FCL had a big cookout for the contractors with a steak dinner for everyone,” notes Harville. “They really went over and above on that.”

The Orndorff & Spaid team credits the effort of all companies involved for the success of the project. “The steel contractor was phenomenal, and FCL did an excellent job of coordinating everything,” Spraker says.

The large gutter featured internal and external hangers. Photo: Orndorff & Spaid Roofing Inc.

The manufacturer also did an excellent job, notes Harville, who commended the work of Melissa Duvall, the JM sales rep on the project, and Barney Conway, the field rep, who visited the site at least once a week. “JM did a good job keeping us well stocked with material and getting us deliveries when we needed them,” Harville notes.

The team members at Orndorff & Spaid believe their confidence comes from experience and knowing that most of the variables are under control. “A lot of that has to do with the equipment we can bring to bear when we need to,” Harville states. “We control the logistics all the way through. Most companies are going to rent a crane or hire trucking — we do all of that. We have our own lifts, we have our own cranes, we do all of our flatbed trucking. We bring a unique process to the table. Beyond that, and our project managers are well versed at doing this. It’s not our first rodeo.”

TEAM

Architect: MacGregor Associates Architects, Atlanta, www.macgregorassoc.com
General Contractor: FCL Builders, Chicago, www.fclbuilders.com
Roofing Contractor: Orndorff & Spaid Roofing Inc., Beltsville, Maryland, www.osroofing.com

MATERIALS

Membrane: 60-mil TPO, Johns Manville, www.jm.com
Insulation: Two layers of 2.5-inch ENRGY 3 Polyisocyanurate, Johns Manville
Skylights: Dynamic Dome Skylights Model 4896, VELUX, www.veluxusa.com

Ponding Water Basics: Proper Drainage Design and Low-Slope Roofs

Roofing professionals install a new asphalt roof on the Broward County Stephen Booher Building in Coral Springs, Florida. Photo: Advanced Roofing Inc.

A low-slope asphalt roofing system is cost effective, durable and reliable. Multiple layers of weatherproof membranes protect a building, its residents and the property it houses. There are a few design elements that will help building owners get the most from their roofing system. Managing ponding water is essential to properly maintaining a roof.

Ponding water is defined as the water which remains on a roof 48 hours or longer. Water may accumulate on a low-slope roof due to rain, snow or runoff from rooftop equipment. Ponding water can have major negative consequences, regardless of the type of roofing system. Proper design, installation and maintenance of roofing structures can prevent this condition and its associated problems.

The adverse effects of ponding water on roofs can include:

  • Deformation of the deck structure:Ponding water can substantially increase the load on roof decks. As water accumulates, deck deflections can increase, thereby resulting in additional ponding water, which could compromise the structural integrity of the deck.
  • Damage to the roof surface:Ice formations develop and move constantly with changes in temperature. This movement can “scrub” the roof membrane to such an extent that considerable physical damage to the membrane can occur.
  • Growth of algae and vegetation:When water stands for long periods of time, algae and vegetation growth will likely occur, and may cause damage to the roof membrane. Additionally, vegetation can clog drains and cause additional ponding.
  • Accumulation of dirt and debris in the ponding area:Dirt, debris, and other contaminants can affect and damage the membrane surface. The can also lead to clogged drains.

Proper design and installation are crucial factors in roof system performance. This photo shows an Atactic Polypropylene (APP) modified bitumen membrane being applied by torch to a low-slope roof. Photo: ARMA

Ponding water may lead to accelerated erosion and deterioration of the membrane surface that can result in failure of the roof system. Allowing even relatively small amounts of moisture beneath the roof membrane may reduce the thermal efficiency of the insulation. More importantly, moisture intrusion can cause serious damage to the deck, insulation, and membrane as well as the building’s interior.

The Asphalt Roofing Manufacturers Association (ARMA) recommends that roof designs provide adequate slope (minimum of ¼ inch per foot) to ensure that the roof drains freely throughout the life of the building and to thereby avoid the effects of ponding water. Model building codes also require a minimum ¼ inch per foot slope for new construction projects, and require positive drainage for re-roofing projects. These requirements are intended to prevent water from ponding on roof surfaces.

Managing Ponding Water

Here are a few best practices to manage ponding water:

  • Adequate sloping should be taken into account during the design process. A roof’s structural frame or deck should be sloped, and drainage components like roof drains and scuppers should be included in the design.
  • In addition, secondary (or emergency) drains may be required by local plumbing codes to help reduce the risk of a structural failure due to clogged drainage systems. Talk to your roof membrane manufacturer and/or roof system designer to determine the proper location of these components.
  • If a deck does not provide the necessary slope to drain, a tapered insulation system can be used. A combination of different approaches — single slope, two-way slope, and four-way slope — is often used to achieve the necessary slope and to allow for moisture drainage.
  • Additionally, crickets installed upslope of rooftop equipment and saddles positioned along a low-point between drains, can help prevent localized ponding in conjunction with a tapered insulation system.
  • Building designers and owners should work with contractors and roof manufacturers to determine which methods are best and appropriate for a roof assembly’s long-term performance, whether it’s a new construction or re-roof project.

The NRCA Roofing Manual: Membrane Roof Systems—2015, states the following: “NRCA recommends that designers make provisions in their roof designs for positive slope.”

The manual spells out that slope generally is provided by:

  • Sloping the structural framing or roof deck
  • Designing a tapered insulation system
  • Proper location of roof drains, scuppers and gutters
  • A combination of the above

By following the proper drainage practices detailed above, building owners can positively impact their low-slope roofing system and help to ensure it will remain durable and reliable throughout its service life.

To obtain specific information about ponding water on particular products and systems, contact your roof material manufacturer. For more information about low-slope asphalt roofing systems, visit www.asphaltroofing.org.