|Point eleven - The
big one. Acrylic additives
This is the big one The greatest crack preventing discovery
we have made is the use of acrylic additives in the finish coat.
several types and brands available. The major use
of acrylic admixtures has been in swimming pools, as a method of
portland cement mortar to concrete. Acrylics have been also used for
cement plaster to cast in place concrete, and other substrates that are
normally too slick, too porous, or not porous enough for a permanent
I started using acrylics in the finish coat in searching for a method to retain the color in mix. Pre-mixed color stucco finishes from California have a small quantity of plastic chemical to retain the color in the mix.
Using acrylics with color not only improved color retention,
but I discovered our jobs had no cracks, or at least very few. There
also were no check
cracks or imperfections from shrinkage, because of the slower final set
of the mortar.
Other benefits of acrylics: Increased bonding strength (of course, they are bonding admixtures):
Improved compression strength.
Few to no cracks due to
No need to wet the wall before
applying the finish coat, which causes
Reduced porousness, reducing
water infiltration, and spalling.
Reduced likelihood of
The increased material cost is about 50 cents a square foot, but the the overall quality of the finish product is vastly superior, so I have no problem charging more for my jobs.