Roof Joist Thickness

The difference in the joist sizes applies to the width of the boards which determines the height of the ceiling.

Roof joist thickness.

A 2 by 4 inch joist for instance hangs into the room by 4 inches which may leave the ceiling high while a 2 by 12 inch joist in the same position hangs 12 inches into the room which decreases the ceiling height by 8 inches. This demo version is fixed at 1m clear span. Flat roof joist calculator. Usually 400 450 or 600mm but any value can be used up to 610mm max.

Joist girders serve as primary framing members with simple spans to support concentrated loads for a roof or floor system. This is the distance between joist centres. The full version allows any size. These concentrated loads often include standard steel joists that are in turn supporting steel roof or floor deck.

How thick a roof is depends mostly on the size of the rafters used in the roof construction but there are additional elements including the thickness of the roof sheathing and the thickness of the shingles you choose. Featuring trus joist tji joists for floor and roof applications. The thickness of plywood used for roof decking depends on the roof slope the spacing of rafters and the weight of other material to be put over the decking as well as the design load the. The roof s main job however is to protect the interior of the house and personal belongings from the outside elements.