3 Reasons Why Stucco Can Crack
Ask any stucco and drywall contractor Scottsdale AZ and he or she will tell you that cracks in the surface are not always a cause for concern. Cracking is natural for a cementitious product such as stucco, and a little bit is to be expected. It is only when the cracking becomes excessive that there is cause for concern about degradation of the stucco assembly.
Even though some cracking of stucco is normal, you may observe that newer houses have more cracking than older homes do. This may be the result of changes to construction techniques since the 1950s or practices that are not quite up to code.
- Stucco Thickness
Stucco is to be applied to a minimum thickness of seven-eighths of an inch to be up to code. However, some contractors cut corners and only apply three-quarters to five-eighths of an inch.
- Plywood Sheathing Installation
The American Plywood Association recommends that when installing sheathing, panels should be separated by one-eighth of an inch at minimum. Instead, it is often installed end-to-end, with abutment of the edges. It is not clear whether installers are not aware of the recommendation or are aware and willfully ignore it. Whatever the case, it can result in cracking because when the plywood swells with weather conditions, there is no space to accommodate it. As a result, the swelling gets deflected outward.
- Lumber Changes
The lumber used for studs in construction prior to the 1950s came from much older and sturdier trees. Due to legitimate environmental concerns, old growth trees are no longer harvested for construction. In the past, the studs were also kiln-dried and cut to a size of two inches by four inches. This has since been reduced. All of these changes have resulted in more warping and bowing of studs, resulting in stucco cracks.
Despite some expected cracking, stucco remains a durable home exterior. Unless cracks are large and excessive, they are not cause for concern.