A custom home builder called the other day to ask a question. “My stucco contractor wants to add anti-freeze to the mix as he’s putting on the scratch coat tomorrow and there is a frost warning.”

My first response, after picking myself up off the floor, was, “what is he nuts.” This is so typical of what we find out there today. Most of the masonry contractors as well as the general contractors do not know what their doing. The answer lies in understanding the codes. The IRC (International Residential Code) 2006 references (for the first time) the ASTM Standard C-926 and ASTM C-1063. These two standards detail exactly how hard coat stucco and lath should be applied. ASTM C-926 Section 4.5 Water states: Water used in mixing, application, and finishing of plaster shall be clean, fresh for domestic consumption and free of such amount of mineral or organic substances as would affect the set, the plaster, or any metal in the system. Obviously, adding Ethylene Glycol (anti-freeze) does not meet the requirement of “fresh for domestic consumption” unless you have a death wish.

If you are in the process of building a home with a stucco exterior or you are about to have your stucco removed and replaced because it wasn’t applied correctly the first time, give my office a call.

Craig Camel

Advanced Mold Diagnostics