Knee Wall Roof Supports

Unlike other kinds of knee walls this kind of wall extends all the way to the rafters but because of the slope of the roof it is shorter than a full height wall.

Knee wall roof supports.

A knee wall is a short wall typically under three feet one metre in height used to support the rafters in timber roof construction. Ching defines a knee wall as a short wall supporting rafters at some intermediate position along their length the knee wall provides support to rafters which therefore need not be large enough. In most instances they are no taller than 3 feet but some builders may custom fit them according to the roof s shape and size. How to stabilize a knee wall.

Purlins as shown in sample photos below are installed for rafter support. If you have existing brackets use one for reference. The out of plane loads are transferred to the floor system through a thick plate nested in the flanges of the member with two diameter fasteners or one diameter fastener for 250mw used for the connection. Knee walls are short usually wooden walls installed around the sides of an attic where the rafters meet the floor.

In his book a visual dictionary of architecture francis d. Knee walls are most commonly seen in bathroom settings where they separate a toilet niche from a countertop or provide a small separation between a vanity and a shower. You can see the image below for an example of a knee wall. The knee wall forms the wall of the attic room and it also creates an enclosed space under the eaves behind the wall.

An important notation is that the purlin bracing should be off of walls or beams as needed. Midwall is designed to support out of plane loading in cantilevered partial wall systems that are unsupported at the top track.