Flat Roof Framing Design

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Flat roof framing design.

2x framing wood joists timber framing laminated beams steel concrete or sips. 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. In order to build any but a shed type roof including trusses you ll need to first determine a few factors. When framing a flat roof you will need to create a slight incline.

This will help you create a flat roof framing plan. Think of a flattened hip roof. 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. Underneath the basics flat roofs are usually constructed with a ceiling nailed to joists which support a deck usually wood in residential construction a vapor barrier insulation and a roof board.

Roofs are framed in five basic designs. 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. Depending on the span many different materials can frame a flat roof. The gable is the most common and it can be complicated with multiple roof lines including valleys and dormers.

It is not ideal for snow or heavy rain but modern materials and proper drainage have helped. Flat roofs are always built at a slight incline at least 1 8 inch per foot. A flat roof has a slope of 1 8 per foot to 2 12. Flat roofs aren t architecturally logical as rain and snow will shed much more quickly off a sloped roof.

The steels or rsj s rolled steel joists are often built into one or both walls to give added stability to the roof structure. Flat roof framing is relatively straightforward. From there the flat roof system you choose will determine the materials you apply. You can do this with a foam layer that exactly fits your roof.

Building a flat roof right. Some roofs actually slope in several directions ensuring optimal water runoff. It can be framed like a floor system with horizontal framing members at 16 19 or 24 o c.