Stucco Expansion Joints

Why are Stucco Expansion Joints Important?

The stucco facade on any building will expand and contract with temperature changes.  This alone would not cause any problems if the temperature changes were uniform across the entire facade, and the building structure that it is attached to, expanded and contracted at the same rate.  Unfortunately, different materials have differing properties and will expand and contract at different rates. As your home is built with many different materials, such as wood, metal or plastic, different areas of your home will expand and contract at different rates.  These differences can lead to cracking and delamination of the stucco, in addition to breaking away from adjacent surfaces and leaving an open channel for water intrusion. This can lead to severe moisture damage of the substrate (sheathing) and framing of the home.

Expansion joints installed into the stucco application will absorb the stresses of uneven expansion and contraction.  In addition to this, over the years, a typical home will compress or “squat” an average of ½ inch per story. Expansion joints will work to prevent this movement from damaging the stucco application, avoiding unsightly cracks and damaging gaps.

Many homes were built without stucco expansion joints.  Expansion joints cannot be retrofit into existing stucco buildings, but some steps can be taken to help prevent this from developing into a serious and damaging situation.  Kerf cuts can be made between the stucco and dissimilar materials, predominantly windows and doors. These cuts are then sealed with an elastomeric caulk product which will act to absorb some of the stresses and strains caused by expansion and contraction. Essentially, they act as secondary expansion joints, but they are of course, limited to the areas where the building has windows and doors installed.

Expansion joints are now required in stucco buildings by modern building codes, this unfortunately does not help the myriad of homes and buildings built prior to the recent code changes.  Call us at Yost Stucco to see what we can do to help.