Butyl Seals Without Hardening

The #8660 single-component non-skinning butyl provides adhesion and a permanent seal where a non-hardening weather seal is desired.

The #8660 single-component non-skinning butyl provides adhesion and a permanent seal where a non-hardening weather seal is desired.

Lucas has added #8660 single-component non-skinning butyl to its product line. The #8660 provides adhesion and a permanent seal between concealed end-laps, metal roof panels, standing-seam roof panels, ridge cap, wall panels and other applications where a non-hardening weather seal is desired. This product is a suitable material for OEM and shop assembled metal details. The #8660 comes in a neutral color, guns easily in cold or hot weather, and is packaged 12 per case.

A Watertight Warranty Convinces HOA to Select Standing-seam Metal Roofing

When you know you can do a good job and you know you’re working with good products, you don’t mind being held accountable. On Top Roofing of Park City, Utah, recently completed a demanding roofing project and supplied the homeowners association with a watertight warranty.

With a strict spec from the consultant and a watertight warranty to back up the work, a standing-seam metal roofing system installed by On Top Roofing was selected for Cache Condos

With a strict spec from the consultant and a watertight warranty to back up the work, a standing-seam metal roofing system installed by On Top Roofing was selected for Cache Condos.

Homeowners associations, or HOAs, have been known to provide challenges to roofers, especially metal roofing installers. The only thing more daunting than an uneducated HOA board is an HOA board that was forced to learn about roofing. The HOA board at the Cache Condos in Park City knows roofing.

The original roof on the condos was a cedar shake that lasted more than 20 years, but a little more than five years ago, it was starting to fail. The board elected to go with a corrugated metal roof with a rusty look.

“In the five years they had that corrugated roof, they had more trouble with leaks than they did in 20 years with the shake roof,” says Jeremy Russell of On Top Roofing. “It was a bad install by a company no longer in business. So they hired a consultant—a consultant who insisted that all details be installed to specification. That’s what we do.”

First, the consultant and the board had to be re-sold on metal roofing for the Cache Condos. The rusty 7/8-inch corrugated metal roof installed just five years ago was installed with exposed fasteners, was rusting in flashing areas and leaking in the laps when snow built up on the roof. With a strict spec from the consultant and a watertight warranty from Drexel Metals to back up the work, a standing-seam metal roofing system installed by On Top Roofing was selected.

“One of the requirements was we had to inject the seams with butyl,” Russell says. “So we purchased a Hot Melt [Technologies] system. It was a huge investment, but we were happy to do it. It was something we’ve wanted to do and this project got us to take that step.

“We received plenty of support from Drexel, putting everything together to meet the requirements of the consultant,” he adds. “We worked out all the details to spec and added some of our own that were above spec.”

One requirement was to use no exposed fasteners. That meant employing stainless-steel material in many of the details: skylights, chimneys, roof to wall flashings. “We etched it, primed it and painted it with automotive paint to match,” Russell notes. “It took more time, but it will not leak.”

One requirement was to avoid exposed fasteners, which meant employing stainless-steel material in many of the details: skylights, chimneys, roof to wall flashings.

One requirement was to avoid exposed fasteners, which meant employing stainless-steel material in many of the details: skylights, chimneys, roof to wall flashings.

More than 33,500 square feet of 22-gauge Galvalume 1 3/4-inch snap-lock standing-seam panels—all formed onsite—were installed by Russell’s crew. The roofing panels, rollformed on one of On Top Roofing’s two New Tech Machinery rollformers, were PVDF-painted in Medium Bronze. The project took about eight months to complete and On Top Roofing wrapped up in November 2014.

“We issued the warranty in December 2014,” says Frank Oswald, warranty inspector for Drexel Metals. “I’d say Jeremy went above and beyond what a typical installer would have done on this project. I was at this site on three different occasions because this project was really under a microscope. Ultimately, we’re quite satisfied with the work and the install.”

Rooftop Equipment Mounting and Penetrations for Low-slope Standing-seam Metal Roofs

Standing-seam metal roofing offers a durable, sustainable alternative to other roof types and can provide maintenance-free service for five to 10 decades. Sadly, this exceptional lifespan often is sabotaged with the mounting of essential rooftop equipment and ancillary mechanicals.

Metal roofing can make use of special seam-clamping hardware that grips the standing seam without puncturing the membrane. Seam clamps have made metal roofing a preferred roof type for mounting photovoltaic solar arrays. PHOTO: Metal Roof Advisory Group Ltd.

Metal roofing can make use of special seam-clamping hardware that grips the standing seam without puncturing the membrane. Seam clamps have made metal roofing a preferred roof type for mounting photovoltaic solar arrays.

Regardless of the roof type involved, consultants generally agree that the best way to prevent roof-related problems is to clear the rooftop of everything possible and just let it function as a roof—not a mechanical equipment platform. However, such a perfect roof continues to elude us, as it becomes necessary or convenient to mount HVAC equipment, screens to hide it, piping to fuel it, scuttles to access it and walkways to service it. The list of rooftop mountings also may include plumbing vents, satellite dishes, lightning protection, snow retention systems, solar collectors, advertising signage and fall-protection systems to maintain all the foregoing. To help achieve relatively trouble-free roofs, this segment provides some basic understanding of the dos and don’ts in situations where rooftop equipment mounting is requisite.

Penetration-free Attachment

A good “first rule” about any rooftop mounting is to avoid penetrating the membrane whenever possible. While this may seem obvious, the tenet is often violated with standing-seam metal. The norm for attaching things seems to involve anchoring the item to the structure through the roof. When this happens, it not only threatens weather integrity, but can also violate the membrane’s thermal-cycling behavior by inadvertently pinning the panel to the structure. Such a point of attachment will fatigue and fail from forces of thermal expansion within a short time. Fortunately, scores of items and equipment can be securely mounted to metal rooftops without any penetration whatsoever, actually making metal roofing more user-friendly than other roof types.

In terms of mounting ancillaries, metal roofing can use special seam-clamping hardware that grips the standing seam without puncturing the membrane. Unlike many other types of roofing, metal is a rigid, high-tensile material. The seam area creates a beam-like structure that can provide convenient anchorage for walkways, solar arrays, condensing units and gas piping without harming the roof’s weathering characteristics. Mechanicals can be safely and cost-effectively secured to these seam clamps, leaving the roof membrane penetration free. Seam clamps can provide holding strength of up to several thousand pounds on some profiles and gauges, last the life of the roof and preserve thermal-cycling characteristics. Using seam clamps when possible for ancillary mounting will eliminate unwanted holes and other potential problems.

Seam clamps allow even cumbersome ancillary items to be attached to metal roofs without penetrating the rooftop. PHOTO: Metal Roof Advisory Group Ltd.

Seam clamps allow even cumbersome ancillary items to be attached to metal roofs without penetrating the rooftop.

Clamps should be made only of noncorrosive metals—typically, aluminum with stainless-steel mounting hardware. These metals are compatible with virtually anything found on a metal roof, except copper (with which there are dissimilar metallurgy issues). Dissimilar metals in electrolytic contact will induce galvanic corrosion of the less noble metal. In cases involving copper roofing, brass clamps should be used with stainless-steel hardware.

Seam clamps generally integrate with the profile and seam folding, and in some way “pinch” the seam material to anchor them in place. Preferred methods of doing this involve setscrews tightened against the seam causing a detent in the seam material that in turn creates a mechanical interlock of the setscrew, seam and clamp, providing the greatest holding strength and durability. Setscrews should have round, polished points to prevent galling metallic coatings, which can lead to corrosion. In like fashion, and regardless of the method of engagement, any clamp device should avoid any sharp points or nodes that could potentially pierce or gall metallic coatings of steel or cause fatigue and fracture points of other metals.

It also is important to remember that any loads introduced into the clamp will be transferred to the panels and their anchorage to the structure. Consequently, anchorage must be capable of withstanding the added load. The best practice is to utilize clamps that have been appropriately tested for material and seam-specific holding strength; be sure in-service load does not exceed that of the published holding strength, including factors of safety. The roof manufacturer should also be consulted with respect to approval of devices used.

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