Self-flashing Skylights on Commercial Warehouses Are Beginning to Leak

Today, many commercial roofers are dealing with a large-scale problem—reinstalling and replacing leaky self-flashing skylights on commercial warehouses. I have seen firsthand how improper installation of self-flashing skylights has become a headache for commercial property owners.

many of the skylights installed on commercial warehouse properties in the western Sunbelt states were installed improperly because they were installed first and foremost as fall protection for the open floor in the roof during construction by the builder and not by the roofer.

Many of the self-flashing skylights installed on commercial warehouse properties in the western Sunbelt states were installed improperly because they were installed first and foremost as fall protection for the open floor in the roof during construction by the builder and not by the roofer.

Around the late 1970s and early 1980s, intermodal freight became a huge part of global distribution. To handle the increase in freight projects, warehouse construction exploded. The Port of Oakland, for instance, invested heavily in intermodal container transfer capabilities in the ’80s. In fact, the aggressive growth of intermodal freight distribution continued into the early 2000s.

The cheapest and easiest way for skylights to be installed on these warehouses was to use self-flashing skylights. The metal curb or L bracket attached to the bottom of the skylight was, in theory, supposed to be set on top of the built-up roofing material and then stripped in, sandwiching the flange between he roofing layers. The result would be roofing material, then skylight, then more roofing material over the flashing on the skylight.

Unfortunately, many of the skylights installed on commercial warehouse properties in the western Sunbelt states were installed improperly because they were installed first and foremost as fall protection for the open floor in the roof during construction by the builder and not by the roofer. Our teams have seen thousands of these original self-flashing skylight installations where self-flashing flanges are set directly on the plywood roof deck, below all the roofing materials.

Most of the original roofers didn’t budget in the time and money it took to pull the skylight assembly apart from the roof deck and re-install it the proper way. Nor did they wash the oils off the new metal from the galvanizing process or use asphalt primer to prep the steel flanges of the assembly and ensure the roofing asphalt would stick properly. Over the years, as the metal of the skylight flanges expanded and contracted and the built-up roof did the same, but at a different rate, the roofing system eventually separated from the skylight, leaving a self-flashing skylight that’s now turned into what we jokingly refer to as a “self-leaking skylight”. This is part of the reason why everyone thinks skylights always leak.

The best way we’ve found to install leak-free skylights on a commercial warehouse roof, especially when re- placing the self-flashing skylights on an existing building, is to use a curb-mounted skylight. A curb-mounted skylight fits like a shoebox lid over a new curb the roofing contractor fabricates as part of the installation. This curbed design eliminates the metal flange and offers waterproofing redundancy in critical areas of the installation, so water can’t get into the building at the skylight opening. Because the new skylight is installed on a curb, it’s also much easier to address any future issues with the skylight or to replace it down the road if necessary. This especially comes in handy when owners lease to new tenants. New building occupancy regulations mean skylights may be required by municipalities to be changed out for smoke vents to comply with fire codes.

If you’re dealing with one or more self-flashing skylight leaks, there are a few things to keep in mind:

  • Check if there is condensation on the inside of the skylight; a lot of skylights have a trough where condensation runoff will leak into the building.
  • Be sure to check the juncture where the skylight and the roof meet (the skylight base flashing), which can sometimes include up to 5 inches of mastic at the base flashing.
  • If the skylight has a frameless acrylic cap without a metal frame around the outside, check the acrylic dome for stress cracks. It is possible to replace some acrylic domes on some skylights but often the cost of an acrylic dome is roughly the same as the cost of a new skylight, and if you’re already considering installing a new roof with a 15- to 20-year warranty, it doesn’t make much sense to leave the “self-leaking skylight” frame in place. Replacing the skylights during the reroofing project is much more cost-effective than re- turning to replace skylights later. In addition, skylight technology is far better now than it was 15 or 20 years ago (think about today’s impact-resistant polycarbonate and better UV and fall protection).

Above all else, don’t let self-flashing skylights give you and your roofing business a bad name. Instead, address the issue with your commercial clients and educate them about the best choices for their skylights and how they can stay current with the International Building Code and municipal codes. You’ll be helping them protect one of their biggest assets by ensuring their skylights stay leak-free.

PHOTOS: Highland Commercial Roofing

Today’s Roofs Provide Additional Square Footage for Developers and Owners

How much traffic can a roof system bear? The fact is, live loads on roofs are getting much bigger as building developers and owners seek to allow more indoor-outdoor uses and rooftop amenities, such as seating areas, gardens and even fire pits and pools, which draw people to the roof. Plus, the dead load may be increasing thanks to those living material installations, such as planters and vegetative roof gardens. These assemblies usually require or hold water—adding to the dead load—as well as frequent maintenance and inspections, which mean a few more people (and more live load).

Muzeiko, a 35,000-square-foot LEED Gold children’s science discovery center in Sofia, Bulgaria, includes a rooftop science play area with a lush green roof, climbing wall, rain garden, outdoor activity space and an amphitheater. PHOTO: ROLAND HALBE, COURTESY LEE H. SKOLNICK ARCHITECTURE + DESIGN PARTNERSHIP

Muzeiko, a 35,000-square-foot LEED Gold children’s science discovery center in Sofia, Bulgaria, includes a rooftop science play area with a lush green roof, climbing wall, rain garden, outdoor activity space and an amphitheater. PHOTO: ROLAND HALBE, COURTESY LEE H. SKOLNICK ARCHITECTURE + DESIGN PARTNERSHIP


“We’ve known the benefits of a green roof from a water-management point of view for some time,” says Joshua Zinder, AIA, principal of JZA+D, Princeton, N.J., noting that more than 70 percent of the water that hits the roof is absorbed. “Increasingly, we see the roof as an opportunity for generating revenue or enhancing the value of the building. One of the ways we’re now helping developers reposition older office and industrial properties is by determining if we can create roof farms or indoor-outdoor spaces not only on the ground floor, but also on the roof planes.”

The case of the rooftop garden with public access is a growing trend, too, and “one must ensure that the roof structure has the necessary structural capacity to support rooftop activity,” notes Kelly Luckett, author of Green Roof Construction and Maintenance. Local codes vary for live loads and dead loads, he explains, and the project team calculates the green roof assembly as part of the total dead load. “Water in excess of that which saturates the growth media, snow and people visiting the green roof are all considered part of the live load of the structure,” Luckett adds.

Just as important, the roofing system has to resist the wear and tear of the live loading. The three main concerns for exposed structural elements, such as roofs, balconies and terraces, are protection from weathering, water ingress and environmental damage. Pedestrian walkways must also ensure long-term durability.

A look at the latest trends in “activating rooftops” reveals even more reasons for roofing contractors, architects and facility owners to look more carefully at specification documents and installation methods for these live-load roof zones.

A new Department of Sanitation complex in New York City, designed by Dattner Architects with WXY Architecture + Urban Design, both of New York, features a dynamic façade of moving metal fins and a 1.5-acre planted roof, which contribute to the LEED Gold operations. PHOTO: WADE ZIMMERMAN, COURTESY WXY ARCHITECTURE + URBAN DESIGN

A new Department of Sanitation complex in New York City, designed by Dattner Architects with WXY Architecture + Urban Design, both of New York, features a dynamic façade of moving metal fins and a 1.5-acre planted roof, which contribute to the LEED Gold operations. PHOTO: WADE ZIMMERMAN, COURTESY WXY ARCHITECTURE + URBAN DESIGN

Skylife and Community

For residential projects with rooftop terraces, careful specifying and installation of green roof assemblies is critical. “We like using liquid membrane roof and extensive green-roof systems, such as sedum carpet,” says Andrew Franz, AIA, LEED AP, principal of Andrew Franz Architect PLLC, New York, adding that the systems work well because the drainage mat is modular, lightweight, and easy to install and adjust—something that is important on uniquely shaped urban rooftop terraces.

Recent projects by Franz include a 2,800-square-foot garden terrace for a family of four in Manhattan. A bluestone floor extends from the dining area to the terrace’s softscape herb garden, further blurring the boundary between in-doors and out. “The green roofing system also includes a protection mat, which protects the roof membrane, a filter sheet of very lightweight soil to protect the drainage mat and the sedum carpet,” Franz says.

Other recent projects with active green roofs demonstrate the benefits of strong PVC membranes, such as at the modern 93 Bright Street townhouse in Jersey City, N.J., designed and developed by Jorge Mastropietro, AIA, whose firm JMA is based in New York City’s Soho neighborhood. Another example, called Trouthouse, designed and built by the Brooklyn-based thread collective, is a showcase of “passive design” principles that reduce energy use, recapture water and even allow for a roof-mounted shade structure that doubles as photovoltaic panels.

The new LEED Gold-certified facility for Gateway Community College in New Haven, Conn., was designed with a vegetative roof to create a new community area on the top floor. According to construction manager Providence, R.I.-based Dimeo Construction, which worked with Providence-based Gilbane Building Co. and the New York office of architect Perkins+Will on the project, the “multi-level student gathering area steps up from the ground floor to a rooftop garden. The green roof also supports photovoltaic panels on a special framing system.”

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Roof Deck Is Noncombustible

USG Corp. has launched USG Structural Solutions; the USG Structural Panel Concrete Roof Deck is among the first products in the portfolio.

USG Corp. has launched USG Structural Solutions; the USG Structural Panel Concrete Roof Deck is among the first products in the portfolio.

USG Corp. has launched USG Structural Solutions; the USG Structural Panel Concrete Roof Deck is among the first products in the portfolio. USG Structural Solutions was designed with the structural engineer and contractor in mind. The products in the portfolio feature a noncombustible formulation (certified by Underwriters Laboratories Inc.), dry application process and ease of handling on the job site. The roof deck creates one- and two-hour fire-rated assemblies. It is strong, durable and dimensionally stable and fits in a standard elevator.

Create a Fire-rated Roof/Ceiling Assembly

USG Corp. has unveiled its USG Securock Brand Concrete Roof Deck Panel.

USG Corp. has unveiled its USG Securock Brand Concrete Roof Deck Panel.


USG Corp. has unveiled its USG Securock Brand Concrete Roof Deck Panel, a durable structural panel that can be combined with other noncombustible materials to create a one- and two-hour fire-rated roof/ceiling assembly. Designed with great uplift ratings and to carry gravity and lateral loads, USG Securock Concrete Roof Deck Panels are mechanically fastened to cold-formed steel joists or framing members, and roof membranes or insulation attach directly over the panels. The panel meets the criteria of ASTM E136-04 for use in all types of noncombustible construction.

Coating a Roof? Don’t Forget Fire Ratings

Fire tests are one of the most important system tests for roof coatings, and it is essential when specifying and applying a coating over an existing roof in a maintenance or repair setting to ensure the roof system’s fire rating is not negatively affected.

TEST METHODS FOR FIRE TESTS

The International Building Code (IBC), first published in 2000, brought together several regional codes into one central, national code and facilitated the acceleration of code adoptions across the U.S. Today, most of the U.S. follows a statewide adoption process for the IBC for Roof Assemblies and Rooftop Structures; some areas do not, which can make code enforcement tricky. Some areas still follow local adoption and may refer to older versions of the code instead of the most current 2012 IBC.

According to the most recent IBC, roof assemblies and coverings are divided into classes A, B, C or “Nonclassified” and are tested in accordance with UL 790 or ASTM E 108. These tests measure the spread of flame, recording whether the material you put on the roof will cause the flame to spread too far on the roof. The UL 790 inaugurated modern fire tests about 100 years ago and, as such, incorporates a century of data and history about roof coatings that may broaden the reach of what certifications the test provides.

“Many see UL 790 as the preferred fire test,” notes Steve Heinje, technical service manager with Quest Construction Products LLC. “It is interesting to note the ASTM E 108 test is deemed by the code requirements an equivalent test.” The ASTM E 108 is a consensus version of UL 790 and can be run by any qualified and accredited test laboratory. Many test laboratories, such as FM Approvals, conduct testing using ASTM E 108.

COMPONENTS OF FIRE TESTING

The roof coating is just one component in the fire rating of a roof assembly; other components include slope, the coating substrate, whether the roof deck is combustible and whether the roof is insulated. These factors, taken together, will determine the roof system’s fire rating.

SLOPE
Although there are exceptions, most fire ratings are done for slopes of under 3/4 inch for commercial roofs, and coatings tend to be recommended for application to a roof with 2 inches or less slope. Slope is an important factor to consider because special coatings may be needed for high slope transitions.

SUBSTRATE
The substrate or membrane type is another vital component of fire testing because the substrate to which the coating is applied could affect the flammability of the roof system. When coating over an existing roof, one should note what existing roofing substrate is being coated over—whether it’s BUR, mod bit, concrete, metal, asphalt or another type of substrate.

COMBUSTIBLE VS. NON-COMBUSTIBLE ROOF DECK
Most coatings are tested over noncombustible decks, but additional and challenging tests are required for the use of combustible decks. It is much more difficult to achieve a Class A rating when covering a wood deck.

INSULATION
Again, it is important to note the materials of the existing roof being coated because these components can affect the flammability of the roof system. Polymeric insulations often reduce the allowable slope for a given system.

PROPER APPLICATION OF THE ROOF COATING

Another significant consideration is that the coating is applied at the appropriate thickness and rate.

“One big thing out of the coating manufacturer’s control is that the applicator uses the recommended or test-required thickness and/or rate at the point of application,” points out Skip Leonard, technical services director with Henry Co. Proper application encompasses parameters, such as the final dry-film thickness, the use of granules or gravel, use of reinforcements and even the number of coats. Accounting for these details is an integral part of installing a rated system.

Once assembled, the roof covering will be granted a Class A, B or C rating by approved testing agencies, typically through UL 790 or ASTM E 108, depending on how effective the roof proves to be in terms of fire resistance. Rated coating solutions exist for just about any existing roof system recover or coating application and often can achieve a Class A rating.

Learn More
Visit the Roof Coatings Manufacturers Association website to locate a roof-coating manufacturer who can help you choose a roof coating most appropriate for your roof system. For more information about roof-coating fire ratings, check out FM Approval’s RoofNav online database for up-to-date roofing-related information or the UL Online Certifications Directory.

Patch a Variety of Poured Roof Decks

SECUROCK Gypsum-Concrete Patch

SECUROCK Gypsum-Concrete Patch

SECUROCK Gypsum-Concrete Patch, formerly known as PYROFILL Gypsum Concrete, is a high-performing patch solution that delivers a professional finish on a variety of poured roof decks. It features more than 500 psi of compressive strength while its fast-setting properties enable foot traffic and fasteners within four hours of application.

  • Easy application to patch many different types of roof decks such as gypsum roof decks.
  • Mill-formulated and composed of specially calcined gypsum and wood chips or shavings.
  • Provides excellent fire performance – non-combustible in accordance with ASTM E136, and it’s fire rated and approved for use in UL Roof Deck Systems (P676, P503, P207, P229, P505, P507)
  • Manufactured to conform to ASTM C317, “Standard Specification for Gypsum Concrete”