Opening Thoughts on Expansion Joints

Expansion Joints are common practice for an architect to detail on drawings and a contractor to install, however, many people who have careers in the masonry field still do not understand the joint completely.

An expansion joint is a vertical joint placed in the masonry veneer and brick related wythes.  This joint will allow movement within the structure due to moisture and thermal changes.

Expansion joint design creates the ability of the veneer to move without structural or architectural finish damage.

Design parameters for expansion joints typically allow greater than 7/16 inch per 100 linear feet of veneer.  Commonly, the expansion joints are placed on an average of every 25 linear feet of veneer starting near the corners and placed at the tops of wall openings.

When constructing the joints, the void must be free of mortar, steel and any type of bituminous fiberboard that can bridge the opening.

To complete the expansion joints, many joints are sealed using a compressible backer rod and either polyurethane elastomeric or polyether sealant matched in color to the veneer.