Stucco is, and will always be, an affordable, impact resistant, durable exterior cladding. And, we all know how long stucco has been around … “Pharaoh, long time.” This hearty cladding we call stucco has been successfully performing as a decorative and durable protection layer for our “things” we keep inside. Bottom line, stucco rocks—pun intended.
So when stucco goes bad, or is perceived to be bad, what goes wrong? To understand potential issues, or the perception of issues, requires the understanding of the assembly, how it is installed and how performance is tied to standards and codes. A prescriptive approach is outlined in ASTM C897 (sand), C926 (stucco application) and C1063 (lath). These standards are the baselines for stucco and outline specifics to mixing, temperature, products etc. This begs the question, if the exact verbiage is not followed, does that mean the stucco is going to fail? Let’s look at the possibilities.