Wood Frame Flat Roof Detail

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.

Wood frame flat roof detail.

Getting the balance right here is crucial as too much weight will inevitably lead to an unstable roofing structure. The steels or rsj s rolled steel joists are often built into one or both walls to give added stability to the roof structure. The basic construction of a flat roof starts with roofing timber that is laid across two upright items usually two walls. The provisions for prescriptive roof construction are found in chapter 8 of the irc and in section 2308 of the ibc.

Flat roofing under construction plywood decking is then used to cover the joists with the width in between also determined by the weight being placed upon them. For additional stability you can also use steel joists that are built into one or both of the walls. 1 8 pitch is given so 24 x 1 8 equals 3 or unit of rise in inches. Of course you don t need to live in a modern house to deal with a flat roof.

This will give additional stability to the roof structure. 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. If the unit of rise in inches is 3 then the cut is the unit of rise and the unit of run 12 inches or 3 12. 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.

Details for conventional wood frame construction the first approach to achieving a strong durable struc ture involving economical use of materials is to follow a basic modular plan for layout and attachment of framing members. From there the flat roof system you choose will determine the materials you apply. Flat roofs aren t architecturally logical as rain and snow will shed much more quickly off a sloped roof. Figure 2 2 roof framing terms.

Conventional light frame wood structures may be built without the need for engineering analysis of each component. This is known as prescriptive framing.