Supporting Roof Rafters Without Knee Wall

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.

Supporting roof rafters without knee wall.

In a sloped roof common rafters run from the peak of the roof down to the top of the exterior walls of the building. Knee walls are short usually wooden walls installed around the sides of an attic where the rafters meet the floor. This indicates that the wall is bearing the weight of those joists supporting upper stories of the home or the roof. Check that the 2 by 4 is plumb with a spirit level.

In his book a visual dictionary of architecture francis d. 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. Collar ties rafter ties tension beams structural ridge beams. A knee wall is a short wall typically under three feet one metre in height used to support the rafters in timber roof construction.

Hold up to the rafter a scrap piece of 2 by 4 lumber a few inches longer than the planned knee wall height with its base on the floor. This article describes and illustrates the different types of support that prevents roof sagging and wall bulging at buildings including definitions of collar ties rafter ties and structural ridge beams. Without support for those spliced boards they ll collapse downwards. You can see the image below for an example of a knee wall.