Terminate Commercial Roofs at the Gutter is a crucial detail many Roofing Contractors overlook or don’t effectively execute during their roof installation. Whether considering a new commercial roof or replacing an old one, there are several important considerations: roofing material, life expectancy, cost, energy efficiency – the list goes on. One component that requires specific thought and care is the means of termination—how will the roofing edge be secured or fastened and how much maintenance is required to maintain the seal for the future?
When fastening down the field membrane edge of a TPO or PVC-covered roof, there are several different options for terminating or securing, your roof at the gutter line and each has pros and cons. Let’s look at these options and review their advantages, effectiveness, and cost.
1. Terminate Commercial Roofs with a Termination Bar
Termination Bar, or T-Bar, is the least expensive option available but is the least effective method of long-term moisture protection. T-Bar requires exposed fasteners to secure the bar above the gutter creating a very susceptible leak point. Each fastener penetrates through the membrane and requires caulk to create a tight seal. There are also maintenance considerations since caulk requires inspection and repair/replacement every few years.
Historically, leaks and roof failures can often be traced to T-Bar fasteners since they create a direct entry point for water. Additionally, T-Bars do not offer any protection from gutter backup problems, which can cause major leaks if the gutter gets clogged.
2. Drip Edge and Cover Strip
Most often used, the metal drip edge is attached with fasteners and covered with an adhesive cover strip that is waterproof and leakproof and looks much cleaner at the gutter line. Since you don’t have the exposed fasteners that you have with T-Bar, there is generally no maintenance required throughout the life of the roof and no penetration to allow water to enter. Most drip edges have an extra “kick” or bend in the metal that helps to divert water away from the building.
On the negative side, drip edge is more expensive to install than T-Bar and requires more skill and precision during installation to prevent leaks during the life of the roof. Also, if a gutter backup or overflow occurs, drip edge is not the most effective at preventing leaks or damage.
3. TPO Coated Drip Edge and Welding
Taking the benefits of drip edge a step further, consider TPO-coated or PVC-coated metal drip edge material that allows for welding to seal the seams. This product is extremely durable, looks great, and, most impressive, is effective against leaks. With expert welds providing the strongest possible hold and seamless protection, there’s no need for annual maintenance.
As with any improved product, welded TPO coated drip edge is more costly than traditional drip edge using cover strip adhesive and requires more skilled craftsmen to install — and it’s only available in white.
4. Drip Edge Gutter Combined
With a Drip Edge Gutter combination, you have a one-piece system that effectively moves water away from the roof and building. This type of system is fabricated out of extremely long-lasting Kynar-coated steel and, like a regular drip edge, is fastened with screws into the decking. The product can be made in any color and is very appealing when properly installed.
With gutter overflow causing a good deal of leakage and water damage in commercial buildings, this is the best way to permanently correct the problem. With a prefabricated one-piece system, if a downspout is clogged water will not get back into the building.
Certainly, this option will be the costliest, since the gutter system will also be replaced. However, there is virtually no maintenance required and the roof will last for years.
What is the Best Option to Terminate Commercial Roofs?
Replacing a commercial roof is a major capital investment that requires serious consideration. Today’s roofing systems are high quality and built to last; it’s important to match the termination application that will best serve the overall structure.