Q&A: How to Build Daylighting Solutions with No Risk for Leaks


Skylights are notorious for leaks; but they can also provide a wealth of benefits for employees and employers. How can a business enjoy all the perks of daylighting and avoid the terrible headaches of leaks? Mark Schuetz, the owner and president of Replex Plastics has the answers.

Question: Mark, what would you say is the number one concern of commercial builders when considering a daylighting solution?

Answer: I’ve noticed five or six most common concerns that commercial builders speak about when considering daylighting solutions, but I’d say what concerns people the most is leaking.

Q: What causes leaks in skylights?

A: Joining dissimilar materials. Leaks typically happen where an acrylic or polycarbonate bubble meets the metal frame. Metal and plastic contract in the cold and expand when exposed to heat at different rates, which shears off the sealant between metal and plastic. A typical unit will last a few years, but too many winters and summers eventually have extreme events that lead to a leak.

Q: If this degradation takes place over years, how can a manufacturer test for leak resistance?

A: Accurate testing requires temperature test chambers that are large enough to test a full size skylight product from oven to freezer. A skylight should be tested from -40F to +150F in environmental test chambers that simulate weather with temperature extremes – only then do you know you’ll have a product that can handle virtually anything. This is a much more rigorous test than is required by US architectural codes, but it’s well worth it to know that the product won’t fail for decades.

Q: What do existing skylight manufacturers do to prevent leaks?

A: A typical leak prevention “solution” in the industry is to tightly bond the domes to the frames with silicone or other sealing agents. If designed improperly, during extreme temperature events this sealant can be sheared off. With enough winters and summers, eventually temperature extremes happen and skylight units then will leak.

Q: Are there any other causes of leaking?

A: Condensation can form inside the skylight, which is the result of warm air contacting cold surfaces that are cold due to insufficient thermal insulation. A typical condensation “solution” in the industry is to build daylighting prismatic skylights that use ¼ inch diameter holes in the corners of the aluminum frames to redirect liquid water that condenses inside the building onto the roof deck outside the building. Sadly these holes also permit continuous air infiltration and furthermore are large enough for insects to crawl through. Furthermore the “thermal break” on most skylights is just terrible — only a thin strip of rubber or plastic. We found that adding a thick layer of polyurethane foam can provide great thermal insulation. Even if it’s very cold outside and warm and humid inside, there is almost no chance of condensation forming.

Q: Are skylights foolproof if they’re designed correctly?

A: No — they still have to be manufactured. The welding, riveting, laser cutting and assembly all have to be perfect. On-site assembly outside of the controlled environment of a manufacturing plant leaves much room for error, so going with a fully assembled solution is the safest bet.

Q: Why is it important to be leak-proof?

A: Skylights are supposed to add value to your asset: your building. Leaks reduce value, and fixes such as holes and drains only hold off the leak from entering the building — for a while. Any commercial building owner would understand the costliness of leaks over time and the importance of long-term prevention.

Q: Is it even worth adding daylighting when they open commercial builders up to new risks?

A: Properly engineered and manufactured daylighting solutions reduce the risk of issues like leaks, yellowing over time, heat/loss and gain, air infiltration, or insufficient light admission. When risks are mitigated, the return on investment is significant: building values increase, employee health and efficiency improves, energy bills drop, and sales per square foot increases. Properly built and installed, daylighting really only adds value to commercial buildings, since the risk is no higher than any high quality roof.

Leaking: it’s a buyer’s main concern before they invest in skylights. But well-designed, thoroughly tested daylighting solutions that are tested and proven to withstand extreme temperature changes and are manufactured in the factory rather than out in the field provide a host of amazing benefits and dramatically reduce the risk of leaking. Commercial building owners can rest easy knowing their daylighting solution will last for decades to come.

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11 Mount Vernon Avenue
Mount Vernon, OH 43050 
1-800-886-8847 (U.S.A Only)



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