Problem With My Elastomeric Paint

by Ian

I had my exterior stucco painted with elastomeric paint, apparently an acrylic blend, in December of 2005. Last summer I began to notice a few small thumbnail sized bare spots with primer exposed on the south sun-drenched wall. A few months later in October, I noticed more, and larger, areas of exposed primer around the northeast corner of my house, especially knee-high and below. I have not actually found evidence of paint chips on the ground.

My general contractor and I have been at odds as to what is the best way to fix the situation.



They propose:

Based on the recommendations of Dunn-Edwards we will pressure-wash to clean the surface of dust or dirt, allow it to dry 1-2 days depending on weather, and recoat the surface with 5 gallons of elastomeric paint to be provided by Dunn-Edwards. In order to avoid any weather issues we will follow the Dunn-Edwards Representatives suggestion and wait until May/June, when we can be certain of warm/dry days.

Note they aren't proposing to re-prime the entire stucco surface nor applying two layers of elastomeric. Also, note he's paraphrased their recommendations without providing any official letterhead from the company.

What recommendations could you provide for me as to how to best handle this from a painting perspective?


Answer

The bare areas definitely will need to be repainted. The procedure described will work fine. A primer isn’t necessary for repainting these areas. A problem that can occur in this situation is that the new coating might look a little different than the old coating. This is called "flashing". Darker colors will show flashing more than light colors. My main concern is what happened to the elastomeric coating? A couple of things could be happening.

First, was the house painted soon after the final coat of stucco? All masonry surfaces must cure for a minimum of 30 days before painting. You mentioned the primer is still on the wall. If you rub a finger across the spot is a powdery residue on your finger? If so there might be a problem with the primer or no primer was used and you are seeing the actual stucco finish coat. If a primer was used and is fully adhered to the wall then something else is happening.

You also mentioned the house was painted in December of 2005. If you live in an area prone to cold winter weather the elasomeric paint could have froze or didn’t cure properly. All paints must be applied when the temperatures are above freezing; this includes the night time temps as well. Here in Colorado I stop painting exteriors about mid-November or earlier.

Elastomeric coatings are very thick and need to be applied to a minimum thickness. The minimum thickness depends on the brand. I visited the Dunn-Edwards website and found two different types of elastomeric paints available.

The first is called Endurawall, this elasomeric paint needs to be applied at 17 mills wet thickness per coat and achieve a dry thickness of 15-17 mills. This is very thick. It would take 2 coats to achieve this.

The second is called Flex-Tex, this one needs to be applied 15-17 mills wet and 7-8 when dry. This is doable in one coat.

It seems to me the Endrawall is the more expensive product and is probably better than the Flex-Tex, the thicker the coating the more it will stretch and the longer it will last. Find out which one of these products was used on your house and how many coats were applied.

It’s possible you should have another coat applied to the entire house. You need to contact the local Dunn-Edwards distributor (store) and request to meet with a sales rep at your house. Have him/her check out the entire house. If you find that a lot more than 5 gallons is needed, contact the painter and builder. It’s there responsibly to do the job according to the contract.