Roof Joist Construction Details

I joists in floor and roof applications.

Roof joist construction details.

Domestic roof construction is the framing and roof covering which is found on most detached houses in cold and temperate climates. Areas for economy in basic design and house construction are cov ered in numerous. The provisions for prescriptive roof construction are found in chapter 8 of the irc and in section 2308 of the ibc. Load bearing or primary structure usually constructed in timber in a residential construction.

Within limitations which include among others building size roof pitch and design loads the allowed span for conventional rafters can be selected from tables rather than designed through engineering calculations. Notched roof joists connect and hold the longest 2 sides in place. So the only reason these planks are called roofing joists is because they run horizontally or nearly horizontally to the ground. Joist is a term used in construction for load bearing planks that run horizontally or nearly to horizontally to ground.

The details on this site are recommended for all i joists. I joist construction details. Good installation begins with specification of the correct joist for the application. Joists are placed on edge spaced at 400 600mm centres supported by external and internal load bearing walls.

Such roofs are built with mostly timber take a number of different shapes and are covered with a variety of materials. An additional roof joist is added at each end to hold the other two sides in place. They are ideal for long spans including continuous spans over intermediate supports. Here you can view and download individual floor and roof details for your use.

Because i joists are straight and true it s easier for builders to avoid crowning and maintain a level framing surface. The construction of the flat roof is similar to that of the timber upper floor. With any building material or product sound construc tion and installation practices must be followed to assure durability and trouble free performance. If you don t have autocad you will need to sign up for a free account and use autodesk viewer a web based applications.

Each joist has a 3 5 inch wide nailing flange on the top and bottom virtually ensuring a non squeak floor when properly installed. Conventional construction the engineered solutions are pro vided in a prescriptive format. Joists fit into gaps in the uppermost top plates of the two sides. Alternatively you can download a free viewer by visiting this link and downloading the dwg trueview application.

In addition to floor and roof framing details this guide includes recommendations for cantilevers and placement of web holes.