Roof-to-wall flashing, fastening the roof membrane at the perimeter edge, and accessories
To terminate the membrane against a wall or parapet, the membrane is cut to the junction and fastened at the edge with the membrane stress plates.
At roof-to-wall locations, flashing strips are cut from the roll, according to need. The strips are run “long” on to roof, then trimmed to length, later. When installing, the author’s crew places a few tack-welds on the flashing’s horizontal leg to hold the strip in place pending full seam welding.
Before the flashing strips are folded up the wall, a full bead of caulk is applied along the upper edge and sides. The author uses a non-sag, elastomeric, neutral-cure silicone sealant—Duro-Caulk Plus by Duro-Last roofing systems.
The author’s crew snapped caulklines 6 inches off the wall, then trimmed the flashing strips. A tack-weld can be seen on the lower, right-hand side of the photo.
The flashing’s top edge of the vertical leg is nailed off. Usually, the hail heads get covered with overhanging sidewall shingles, or in this case, window trim under the existing sill.
Lastly, the roof-to-wall flashing seams are welded. Here, the installer welds the horizontal leg a lapped joint. The roof-to-wall flashing’s vertical side lap and 90-degree corner are also welded—all membrane-to-membrane seams are welded with the Leister.
On the perimeter edge, lengths of PVC-clad heavy-gauge stainless steel drip edge were installed on top of the roof’s membrane. The drip edge comes with a weldable PVC coating, which allows for the bonding of cover strips flashing. The author usually installs galvanized and stainless steel drip edge, though copper can be special ordered (the copper has to be pre-made and sent out to have a plastisol PVC coating applied to allow for membrane bonding).
The drip edge was nailed off with stainless steel roofing nails at a rigorous 3- to 4-inch on-center spacing (replacing membrane stress plates along this edge). To finish it off, a PVC cover strip was welded down over the drip edge.
Because there’s a tendency during welding for the membrane to deform at any sharp corners, the author’s crew round off all the cover-strip terminations.
Lastly, the cover flashing’s inside edge is welded to the main roof membrane; the flashing’s outside edge is welded to the drip edge as well. When installed, the PVC cover strip is held back a little bit from the drip edge’s outside edge, so the weld’s bonding can be inspected.
For tricky, three-directional corners, pre-formed outside and inside corner flashing is available from the manufacturer.
Product accessories also include surface-applied profiles (SENTINEL Profile bar) designed to give the appearance of a standing seam metal roof. These extruded PVC profiles (or ribs) are pliable and can be installed on both flat and curved surfaces, and on any slope. They are approximately an inch-and-a-quarter high by an inch-and-three-eighths wide and come in roughly 10 foot lengths.
When installing the rib profiles, first tack-weld them in place to ensure that they are straight prior to final welding. Similar to the seam work, the profiles are hot-air welded to the membrane with the torch nozzle placed under the ribs, then immediately pressed with a seam roller.