New Flat Roof Installation - Parapet Wall & Wall-to-Roof Detailing

Flat roofs that double as walkable outdoor space need an extra layer of thought. The membrane is the waterproofing - it cannot be the wear surface. People walking on a membrane will degrade it over time, and any furniture or planter is going to leave puncture marks where it sits.

The right way to build a walkable flat roof is to install the membrane to a fully-protected standard, then float a pedestal-supported paver system above it. The pedestals lift the pavers off the membrane (creating a drainage cavity), the pavers provide the wear surface, and any maintenance can happen without compromising the waterproof layer below.

This install: tear-off of the old roofing, deck inspection and partial replacement, polyiso insulation for energy code compliance, fully-adhered single-ply membrane, heat-welded seams, integrated flashings at the door threshold and parapet walls, then a paver-on-pedestal walking surface above.

Critical detail: the door threshold from the interior space to the deck has to be properly flashed to drain water away from the interior. Most roof-deck failures we see are at that threshold. Our detail uses a sloped sill pan and an upturned membrane to direct any water onto the field membrane and out through the drains.

Five photos cover the membrane install, the welded seams, the pedestal/paver layout, and the finished walkable deck.