Knee wall

"[1] The knee wall provides support to rafters which therefore need not be large enough to span from the ridge to the eaves.

Typically the knee wall is covered with plaster or gypsum board.

The term is derived from the association with a human knee, partly bent.

Since there is no legal definition of the jamb height, further specifications are required as to how it is to be measured.

It is generally accepted that the knee wall begins at the upper edge of the soffit of the floor below.