Knee Wall Roof Supports

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.

Knee wall roof supports.

An important notation is that the purlin bracing should be off of walls or beams as needed. 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. The knee wall forms the wall of the attic room and it also creates an enclosed space under the eaves behind the wall. Purlins as shown in sample photos below are installed for rafter support.

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. Measure the eave overhang from the exterior wall and add 5 inches to the measurement to provide a reveal or extension on the end of the horizontal beam that supports the eave if desired but you can cut it longer or shorter. Knee walls are short usually wooden walls installed around the sides of an attic where the rafters meet the floor. You can see the image below for an example of a knee wall.

The braces struts or kickers should be within every 4 and should not be at a greater than a 45 degree angle towards the roof slope lower side. In his book a visual dictionary of architecture francis d. How to stabilize a knee wall. 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.

Use pressure treated 4 by 4 beams to build a basic craftsman bracket. If you have existing brackets use one for reference.