Knee Wall

Definition

A knee wall is a short wall under the slope of a roof.

Purpose

The primary purpose of a knee wall is to support the rafters in a sloped roof and create usable space under the roof slope. It is commonly used in attic conversions and rooms with sloped ceilings to maximize floor space and provide support.

Examples of Use

1. Attic Conversions: Knee walls are often installed in attic spaces to create additional living areas, providing support for the roof while allowing for standing room.
2. Dormer Construction: In dormers, knee walls help to define the space and provide a vertical surface for windows or storage.
3. Finished Basements: Knee walls are used in basements with sloped ceilings to create storage areas or partition spaces.

Related Terms

• Rafter: A structural member used to support the roof, running from the ridge to the wall plate.
• Dormer: A window that projects vertically from a sloping roof, often associated with knee walls.
• Skylight: A window installed in a roof or ceiling, sometimes supported by knee walls.

Notes

Knee walls must be properly framed and insulated to ensure they provide adequate support and thermal efficiency. They are a practical solution for maximizing usable space in areas with sloped ceilings.