By Greg Lewis
The short answer is…most buildings should be painted with a high-quality acrylic paint. An acrylic paint job costs far less and is easier to touch up in the future if any damage needs to be repaired.
Elastomeric stucco coatings are also acrylic paints but they are about 10 times thicker than standard acrylic paints which gives it a 300% elongation. This means it is very flexible and stretches. It returns back to its original shape, instead of cracking like a standard acrylic paint would do when your building settles (or moves during one of the hundreds of tremors we experience each year here in Southern California).
The reasons to use an Elastomeric Stucco Coating are:
(1) You are experiencing water damage inside your unit causing costly repairs or
(2) You have unsightly stucco cracking (usually from building settling.
I only recommend elastomeric coating for these two problems; otherwise it is just too expensive since it requires a lot more labor and material than a standard acrylic paint job.
Most buildings are manufactured with a waterproof membrane that is installed between the framing of the building and the stucco. These waterproof membranes don’t usually last more than 30 years before they start to degrade and crack. When this happens, rain water can then pass through to the interior walls and cause damage.
If you are experiencing interior water damage or excessive stucco cracking, elastomeric IS the way to go but you must first check to make sure your roofing and window frames are water tight. If water does get in behind the stucco (from the roof or windows), the elastomeric will blister and look like an inflating balloon of water.
Although elastomeric is expensive, it is far, far less costly than removing the stucco, installing a new waterproof membrane and then re-stuccoing your building. Elastomeric coating should only be used on stucco and other masonry and should not be used on wood because wood needs to breathe.