Manufacturer and supplier of roof products and accessories for the metal building industry since 1964

What Type of Skylight Should You Choose for Your Commercial Metal Roof?

December 30th, 2022 | Eric McClung

There are various types of skylights available for commercial roofs. They differ in framing material, style, and the type of glazing used. Among the most common types of skylights installed are curb-mount, self-flashed, and metal building skylight systems. All are ideal for flat or low-pitched roofs. At R&S Roof Products, we assist you in selecting durable and exceptional quality skylights for metal roofs. We also offer a range of curb mount and self-flashed options for built-up roofs.

Types of skylights for metal roofs


Curb Mounted Skylights

Curb-mount unit skylights are designed to install on a pre-existing roof curb. This may be a wood curb which is often found on built-up roofs, or a metal curb installed on a metal roof. R&S always recommends a standard skylight size as these are generally more cost effective and easy to replace. Switching out the skylight simply involves backing out screws, removing the old skylight and replacing it with the new one. Note the existing curb remains in place so there is no disruption to the roof’s integrity. R&S offers skylight solutions that include both the roof curb and skylight as a packaged kit.

Self-Flashed Skylights

These are skylights that include an integrated roof curb as part of the overall assembly. The benefit of this application is a lower overall cost and reduced installation time. However, there is more involved in replacing these units. Often the skylight glazing must be removed from the assembly, the mounting surface cleaned, and then a new dome is reinstalled using calking and a new retaining cap. This puts more risk on the installer because the replaced dome may leak in the future if not sealed properly.

Metal Building Skylights

Companies that specialize in metal building components may offer specialized skylight systems designed for metal roofs. For example, R&S can supply skylight kits that integrate with Standing Seam or R-Panel roof systems. Our kits include everything needed for installation, including the curb system, skylight, fall protection along with the components required for a weathertight seal. For more information, check out our RS24 for Standing Seam roofs and RS36 for R-Panel roof systems.

All these skylights may be installed as an upgrade to an existing roof or as part of new construction. They come in various sizes, shapes, and materials; and feature glazing options including polycarbonate and acrylic.

Skylight Glazing

There are several styles of glazing available, each with specific benefits. Polycarbonate material is very strong and is often used in high wind / hurricane prone areas. These units are also hail resistant and may be used when blast-proof requirements are part of the building plans. They typically carry a higher overall cost. Glazing can be single dome, double dome or may utilize a honeycomb panel to improve insulation values.

Acrylic glazing offers superior lighting but doesn’t have the same strength when compared to polycarbonate. These units are generally lower in cost and best in areas with low risk of high-wind conditions or hail. Addition of multiple domes or thermal blocks are used to improve the insulation value but lower the amount of light that enters the building.

Prismatic glazing is available in both polycarbonate and acrylic. This type of glazing helps to “spread the light” as it enters the building for a more balanced light condition throughout the day. Skylights also have at least one dome with a white tint. This is critical in creating a haze factor that prevents hot spots (shafts of light) inside the building.

Skylight Frames

The frame holds plastic or glass in place which becomes the curb cap used to mount the skylight to the curb. Frames are a critical part of any skylight system.

A simple non-insulated frame is the lowest cost option but may result in condensation forming inside the building. This is due to cold thermal transfer from the outside to the inside of the frame where warmth and humidity are present. This warm and humid air condenses on the cold frame resulting into water accumulation and dripping inside the building.

A thermally broken frame includes a plastic material that separates the outer part of the frame from the inner part. This design prevents cold thermal transfer allowing the outside of the frame, so the inside frame is consistent with the interior temperature. This prevents condensation from occurring. This is the most expensive option, but also the most effective in areas with more extreme climate conditions.

The last type is a thermal barrier frame which includes an insulated sleeve on the inside surface of the frame that prevents condensation from forming. This is often the best option as it effectively balances cost and performance.

All well-designed skylights should include an integral condensation gutter as part of the frame assembly. This allows any moisture that may accumulate on the dome material to be collected in the gutter which evaporates over time. These should be oversized to ensure the water does not overflow and drip inside the building.

Design, Installation, and Performance Benefits

Care should be taken when choosing the right style of skylight. As such, you should always work with a company that specializes in the design of daylighting systems and can help navigate all the options. R&S can provide this service and help determine the number of skylights required for an optimal layout to maximize daylighting efficiency.

When it comes to preventing leaks, curb-mount or metal roof skylights are both equally effective. Suppliers should have comprehensive installation guides and support to remove any guess work. Condensation issues can also be mistaken for leaks. Proper insulation and thermal barriers eliminate this concern.

Finally, owners should always concern themselves with safety. OSHA compliant fall screens offer a safeguard against fall accidents through skylights. Over time, sun exposure will weaken the plastic glazing making them susceptible to breakage. Skylights have a 10–15-year lifespan depending on the climate. Fall screens mount above or below the glazing with minimal effort protecting against falls after the skylight has surpassed its lifespan.

Daylighting solutions will immediately deliver tremendous value to any building. Natural light results in higher productivity and happiness for workers and customers alike. If the proper system is chosen, skylights will not leak or become a risk to building owners.

For information about the metal roof skylights we offer at R&S Roof Products, give us a call at 800.423.1619 or submit a quote form today.


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