What Is a Full Sheer Wall?

Shear Walls

• A timber-frame shear wall consists of three elements. First, the wall is framed like a typical wall with vertical studs extending between horizontal top and bottom plates. Secondly, the wall is covered with exterior plywood sheathing that ties the wall framing together and helps resist lateral flexing of the wall. Thirdly, the wall is anchored to the structure below it -- either the building's sill plate or the floor below in the case of upper-floor walls -- by means of holdowns attached to the wall's end studs and bolted through the bottom plate. The expanse of wall between holdowns is considered to be an independent shear-wall segment.

Full-Height Shear Walls

• A full-height shear wall extends from the floor to the ceiling with no interruption in the wall's framing or sheathing. Because any loss of wall structure results in a loss of shear strength, a full-height shear wall is better able to resist lateral forces than a wall that is pierced by door or window openings. When openings in the wall are required, the segments between openings are isolated with holdowns so that each section between openings functions as an independent full-height shear-wall segment.

Perforated Shear Walls

• A perforated shear wall has openings that are not isolated from surrounding full-height shear-wall segments by holdowns and are considered to be part of the shear-wall segment. In this case, the openings are referred to as unrestrained openings. Perforated shear walls are not as strong as full-height shear walls. But if they are designed carefully so that the openings are not excessively large, perforated shear walls can meet minimum standards for shear-wall strength.

Concrete Shear Walls

• In earthquake-prone parts of the world, construction utilizing concrete shear walls is common. The design of these walls typically includes horizontal and vertical steel reinforcing beams encased in concrete that is cast in place. The walls are anchored to cast concrete floor slabs, and wall openings are isolated between shear-wall segments similar to that of wood-frame construction.