Wall to Deck Metal Flashing Detail - Polyurethane Waterproof Installation Methods for Deck Coating

Waterproofing contractors, Property Managers, and Engineers ask about metal flashing details: Galvanized or bonderized metal flashing is acceptable for most waterproofing manufacturers. If you are near the ocean, you may want to go with stainless steel or copper - but call us or check with your waterproofing manufacturer as they may have a specific waterproofing system primer they will want you to use with the waterproofing deck system. Polycoat Products is a great source for information. Call (562) 309-3085. 

When installing L-metal flashing, it will typically be 4" L-metal unless you have a special condition. Best practice is to lay the horizontal piece of the L-metal onto a "bed" of polyurethane sealant (2 beads across the area of installation). Then mechanically fasten the L-metal 2" OC, staggered. The L-metal should be firmly secured flat on the deck. The termination of the stucco (weep screed) should then overlap the L-metal vertical piece. Fasten the weep screed with a minimum clearance of 2" from the deck, on the vertical wall, but be sure not to fasten (or pinch) the L-metal's vertical side to the weep screed. Critical detail.

The L-metal and weep screed should be able to move independently from each other. This will prevent either one from coming loose (or ripping out) during movement - and all structures will move, sway, shake, expand, contract, etc. This, like many other small details, is critical to long term success of your polyurethane waterproofing project. 

For more info, call Anthony Perez at Polycoat Products. He is very responsive and is an expert in this field.