Flat Roof Framing Design

Building a flat roof right.

Flat roof framing design.

The gable is the most common and it can be complicated with multiple roof lines including valleys and dormers. Shed gable hip gambrel and mansard. 2x framing wood joists timber framing laminated beams steel concrete or sips. In order to build any but a shed type roof including trusses you ll need to first determine a few factors.

Flat roofs aren t architecturally logical as rain and snow will shed much more quickly off a sloped roof. It is not ideal for snow or heavy rain but modern materials and proper drainage have helped. From there the flat roof system you choose will determine the materials you apply. Think of a flattened hip roof.

A flat roof has a slope of 1 8 per foot to 2 12. If you build a flat roof try to have it slope in multiple directions to drains or gutters. Flat roofs are always built at a slight incline at least 1 8 inch per foot. In the past most were constructed by packing the insulation directly above the internal ceiling finish in between the joists with a ventilation gap above.

Flat roof framing is relatively straightforward. Yet for historic modern style buildings like this old house s cambridge tv project flat roofs are at the core of the architecture meant to reflect the broad horizontal lines of the natural landscape. Some roofs actually slope in several directions ensuring optimal water runoff. On a basic level flat roof construction comes in the form of roofing timbers or joists as they are more commonly known or steels that are laid across two uprights walls in most cases.

You can do this with a foam layer that exactly fits your roof. The span rise run and line length. Roofs are framed in five basic designs. When framing a flat roof you will need to create a slight incline.

It can be framed like a floor system with horizontal framing members at 16 19 or 24 o c. The steels or rsj s rolled steel joists are often built into one or both walls to give added stability to the roof structure. This will help you create a flat roof framing plan.