Flat Roof Assembly Detail

Some observers suggest it s harder to replace a flat roof than a traditional pitched shingle roof because of the labor required to remove its layers especially on older flat roofs.

Flat roof assembly detail.

Of course flat roofs are not flat but have a very slight roof pitch of between 1 4 to 1 2 per foot. The basic construction of a flat roof starts with roofing timber that is laid across two upright items usually two walls. Roof assemblies must control for exterior moisture in a monolithic and complete fashion. Flat roofs are hard to replace.

That will help you remember certain factors and details to build the best possible flat roof. Download free high quality cad drawings blocks and details of roof and deck insulation organized by masterformat. The perimeter of the roof assembly insulation is wrapped to prevent interstitial airflow from the parapet into the multilayered. But now flat roofs often are constructed with fewer layers because of improved waterproofing technology.

Tpo s long term heat uv and natural fungal resistance plus flexibility without need for plasticizers also make tpo a reliable low slope roofing system. In unvented flat or low slope roofs with parapets perform a full flood test to ensure leak free installation of roofing membrane. Test roofing membranes for integrity prior to covering from below. Before constructing a flat roof assembly please refer to the unvented roof assembly comments under 6 2 vented and unvented roof assemblies and if applicable 6 3 parapet walls.

Today s variety of flat or low slope commercial roofing options roof pitches ranging from 12 to 3 12 is no longer simple and has grown considerably in the last 50 years. This is how to detail an unvented roof assembly for flat and low slope roofs. The roof membrane is fully adhered to a coverboard that is mechanically attached to the structural deck in the field of the roof and an allowance for membrane movement is provided at the perimeter of the roof assembly. Just enough slope to drain water but also flat enough to be a problem if not constructed properly.

Having a manual for warm flat roof construction with details and a summary of rules to follow helps. Heat welded seams provide superior strength. Short for thermoplastic polyolefin tpo is a single ply roofing membrane that offers excellent performance at a cost effective price.