Watertight at Night: Keeping Rain Out During a Roofing Project

August 25, 2023

You’re doing a reroofing project because of the leaks. But how can you be sure that while the roofing contractor is tearing off the old roof, rain won’t cause a deluge inside your facility? A professional roofing contractor with years of experience will employ a variety of strategies to ensure moisture stays out of your facility as the project progresses. We’ve outlined some of the tactics that D. C. Taylor Co. uses below.

Work in Sections

Each day the crew scales how much of the old roof is torn off based on their productivity and an estimated amount of roofing squares that can be installed by the day’s end. The entire roof system is rarely removed all at once; only happening at a customer’s request or when a building is unoccupied. Working in sections each day ensures that no part of the roof is left exposed overnight.

Tie-In Every Night

At the end of every day, your roofing contractor will tie in the newly laid roofing system with the existing roof that is yet to be removed. When the old and new roof systems are both the same type of single-ply membrane, it’s as simple as heat welding the new roof to the old for a watertight seam. It becomes more complicated when the roofing systems differ.

If you have PVC and TPO membranes, a peel-and-stick adhesive tape can be used. If you’re replacing a built-up roof with a new single-ply, hot asphalt may be used to adhere the new membrane to the old built-up roofing material.

When roofing with membrane on a metal panel roof, once flute fill insulation is applied, “You put your membrane over the next rib and put weight on it, so the wind doesn’t blow that membrane up,” explains Timm Haefner, Vice President Construction, D. C. Taylor Co., Cedar Rapids, IA.

Sometimes if moisture is present in the existing roof system, water can migrate from parts of the roof that have not been removed yet. If this is a concern, your roofing contractor may tie off to the deck with a termination bar. This takes extra materials and labor though, so expect higher project costs.

When the crew returns to work the next day, the tie-off area is cut off and discarded so the new membrane can be mechanically fastened or heat welded to the next new roll of single-play being installed.

Watching the Weather

A seasoned project manager or supervisor is as vigilant about knowing the weather as a meteorologist. They constantly monitor conditions and may not proceed with work if the forecast shows more than a 30 percent chance of rain. Even when skies look clear and no chance of precipitation is anticipated, they’re still cautious, often having tie-off materials (e.g., kettle, pressure-sensitive tape, primer, or heat weld equipment) ready at all times.

Use Gravity

Another strategy that D. C. Taylor Co. sometimes employs is starting uphill and working down. If water is present in the old roofing system, removing sections of the roof at higher elevations ensures that moisture won’t migrate to newly installed roofing squares (because water doesn’t run uphill).

Even if moisture in the existing system isn’t a concern, this can add extra assurance that overnight rain won’t find its way into the building. “You don’t have as much to worry about it because you’ve created a shingle effect,” explains Haefner.

Start Near the Drain

If you’re installing less insulation than previously used, your old system will be higher than the new roof being laid. In this case, even if the new and old roof systems are tied in every night, a rainstorm could result in ponding water. “In that situation, you start reroofing at the drain and work out. You’ve got to have the drain at a low point so that water drains away,” explains Haefner.

To ease your anxiety about the possibility of moisture infiltration during a reroofing project, ask your roofing contractor what measures they take to keep the roof watertight each night.

To get started on your next roofing project, call D. C. Taylor Co. at 319.731.4118 or email [email protected] today.

Contact Us Today To Get Started On A Quote