Start off by running a thick bead of Liquid Flash at the corner of the rough opening.
Apply it in a serpentine pattern a minimum of 6 inches up the jambs, then across the sill…
…in straight, parallel beads. If you come across any irregularities, such as holes, dips, etc., be sure to squeeze out a little more product to accommodate these voids.
Lastly, run a bead on the outside face of sheathing, starting at one end…
…and finishing at the other. We used one 29 oz. cartridge to complete the sill pan on this 5-foot wide window—framed in a 2x6 wall with 1.5-inch-thick ZIP System R-Sheathing panels.
Spread the product out evenly using spatula, putty knife, or similar tool. Apply a minimum of 2 inches on to the face of the ZIP System sheathing.
Note, Liquid Flash is fairly sticky and has a tendency pull away from itself. So, it’s important to make sure there’s enough product applied for proper coverage, especially at corners.
We found it self-levels a little bit while tooling, so we didn’t have to overwork areas to make them perfect.
When the Liquid Flash becomes opaque (you can't see the substrate underneath), the minimum thickness of 12-15 mils is achieved.
We ended up applying another bead along the sill’s edge to ensure proper coverage at this critical 90-degree turn. Then, carefully tooled the edge.
Liquid Flash is a moisture-curing product; low temperatures and low relative humidity slows drying time while high temperatures and high humidity accelerates it. On the day we applied it, it was moderately humid and in the 70s. It took around 45 minutes to skin over and approximately 4 hours to dry.