Tim, a Polyschool trainer with Polyglass, will now walk you through a proper scupper flashing installation guide using our Elastoflex SA V base sheet and Polyflex SA P granulated cap sheet.
When installing any low-sloped roofing system, care must be taken to ensure that the roof has adequate drainage. If water isn’t allowed to drain away from a roof, it can cause serious problems. One of the best ways to prevent water from building up is to install a scupper outlet for drainage.
Today, we’ll go through a detailed guide to using proper scupper flashing. To keep the scupper flashing watertight, it must be sandwiched between two layers of Elastoflex SA V base sheet. We’ve already installed the scupper in the video below by setting it in a bed of PG 500 roof cement. We then primed it with our PG 100 quick-drying asphalt primer and let it dry to a tack.
How to install proper scupper flashing
Tim, a Polyschool trainer with Polyglass, will now walk you through a proper scupper flashing installation guide using our Elastoflex SA V base sheet and Polyflex SA P granulated cap sheet.
Step One: First, cut a target patch of the base sheet to go over the top of the scupper, making it a minimum of four inches larger than the scupper all the way around. Once you get your piece set, pull the release film and stick it in place.
Step Two: Find the corners of the scupper opening and cut along the edges. Leave an inch of SA V to fall into the scupper. Use a hand roller to create good adhesion, then add a bead of PG 500 asphalt roof cement to the leading edge.
Step Three: Bring the final layer of Polyflex SA P granulated cap sheet up to the wall, extending a minimum of one inch over the cant strip with the flashing extending up the wall. Cut out a square around the edges of the scupper, leaving enough membrane to extend into the scupper one inch past our Elastoflex SA V.
Step Four: Pull the release film on the cap sheet and roll everything into place. Add a bead of PG 500 to help ensure water tightness.
Step Five: Now it’s time to hang the wall flashing. Make a 45-degree cut at the side lap, and then pull the release film and roll it in place, adding additional pressure to make sure it properly adheres.
Step Six: Using a hot air welder, heat the membrane as far back as the cant strip and roll it in to help activate adhesion. You can also use adhesive, like our modified PG 500. Add extra pressure on T joints.
Step Seven: Cut out a square in the wall flashing using the corners of the scupper. At the base of the hole, cut outwards at a 45-degree angle to get the hot welder in. Make sure not to cut the cap sheet underneath. We always recommend using a hook blade.
Step Eight: Any over granule transitions must be treated with heat or adhesive. We’re going to use the hot air welder. Stick the welder in and immediately start rolling as you apply heat to wake up the self-adhering compounds.
Product Summary
Elastoflex SA V
Elastoflex SA V is a premium ply roofing base sheet that features ADESO® Technology – with an SBS modified asphalt compound on the top side and an aggressive self-adhesive compound on the bottom layer. Elastoflex SA V also employs a high-performance reinforced fiberglass mat to ensure excellent stability.
Polyflex SA P
Polyflex SA P is a granulated cap sheet for low-sloped roofs. It features ADESO Dual-Compound Technology with an APP top layer and a powerful adhesive compound on the underside. Polyflex SAP uses tough non-woven polyester reinforcement for flexibility and excellent tear and puncture resistance.