HVAC Tech Coming? Protect Your Roof

June 15, 2021

HVAC units on the roof make a lot of sense – they save valuable real estate inside the building and space on the property. Theft and vandalism is less of a concern, and the systems may even offer greater energy efficiency.

There’s just one disadvantage – potential damage to your roofing system.

Troubleshooting a Rooftop HVAC Leak

Water infiltration? Not sure if it’s a roof leak or HVAC-related moisture? “I would involve both the HVAC and roofing contractor in a leak situation so both parties are present, and the source of water infiltration can be determined,” says James (J. J.) Longerbeam, Vice President Service, D. C. Taylor Co., Cedar Rapids, IA.

Your roofing contractor can perform a water test, where they douse the roof with water for 15-30 minutes to recreate the leak. The contractor may also wet the flashing or take core cuts to check for wet insulation. If no moisture is detected or roof defects discovered, the HVAC equipment may be to blame. Common causes of water are the pre-drilled holes where wires run down into the building from the unit, a blocked condensate line, and a failed gasket or weatherproof seal.

With both roofing and HVAC professionals investigating the problem together, there won’t be any finger-pointing later. You can also be sure that no roof damage is caused during the service call.

Installing a New HVAC Unit on the Roof

If you’re having a new HVAC unit installed, put your roofing contractor in contact with the equipment installer. They can discuss penetrations, appropriate flashing details, and the location of the unit to minimize its impact on the roof (e.g. slope, drainage, excessive weight, etc.).

Plan ahead and make sure the work is performed at a time when both contractors are available. “It may require coordination of both parties to be present for flashing or re-flashing the existing or new HVAC curb with membrane per manufacturer’s specifications,” says Longerbeam.

A roofing crew can remove the membrane and insulation so new curbs can be installed and flashed. Curbs are support structures installed directly to the roof deck. The HVAC equipment sits on these raised platforms, which are flashed with roofing membrane to prevent moisture infiltration into the building. Your roofing contractor should install flashing to ensure a watertight seal. Don’t count on your HVAC contractor to know how to flash curbs with roof membrane.

Time for HVAC Maintenance

Technicians will need to service the HVAC equipment regularly. To prevent damage during HVAC visits, apply the following strategies.

Strategy No. 1: Limit and track who’s on the roof. Besides limiting who has roof access, keep track of it. Have people sign a log with the date and times they’re on the roof. People are more careful not to cause damage when they know they’ll be held accountable.

Strategy No. 2: Educate. Educate. Educate. Once users have signed the roof access log, have them review instructions for working on the roof. This document can provide dos and don’ts for working on the roof, as well as rules and requirements. Your roofing contractor can assist you with the creation of this document. And don’t forget to post signage at roof access points with how to avoid causing roof damage (and reporting it if necessary).

Strategy No. 3: Walk this way. Providing flag stands and flagging, guardrails, pathway marking tape, walkway pad, or an elevated walkway indicates where workers should traverse the roof. In the case of walkway mats/pad or elevated walkway, it also limits damage from foot traffic and restricts activity to designated areas.

“HVAC technicians perform routine maintenance in which they are required to remove doors to access components within the HVAC unit(s) to change filters, etc.,” explains Longerbeam. “The roof membrane can be damaged due to door removal and dropping of tools and or equipment.” If you’re having your HVAC serviced twice a year, schedule your routine roof inspections immediately after. An experienced roofing contractor can inspect the roof for any potential damage that may have occurred.

Contact D. C. Taylor Co. today at 319.731.4118 to schedule a roofing service.

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