When it comes to exterior paint, alligatoring is a term that refers to a network of cracks that can form and ruin the finish. Although any painted surface can suffer from cracking, concrete block walls like those used for many commercial buildings seem particularly prone. The following are a few ways to prevent alligatoring.
1. Make Sure the Surface Is Clean and Prepped
A poorly prepped surface is more likely to develop cracks. Your painting crew must completely wash the exterior wall. Cleaning should include the removal of cracked, flaking, and peeling paint as well. Otherwise, the damage will just continue through to the new layer of paint. Most crews will use a combination of pressure washing and scraping to make sure the wall is ready to accept a new coat of paint.
2. Apply the Right Primer and Paint Combo
A major cause of cracking is not priming the area properly before painting. Primer provides a smooth surface that paint can easily adhere to. The primer must be matched to the paint. This means that oil-based primers can only be used with oil-based paints, and latex primers are only for use with latex paints. Further, the primer coat needs to be cured before the paint is applied.
3. Paint During the Prime Temperature Window
Painting when temperatures are too hot or too cold can affect the adhesion of the paint. When poor adhesion occurs, condensation can form between the paint and the wall. Generally, you want temperatures to be above 50 but below 80 degrees in order to ensure the best adhesion. Most paint brands will provide the best temperature range for their product right on the can. For this reason, early summer or fall is often the preferred time for exterior painting.
4. Avoid Humid-day Painting
You should also avoid bringing in the painters when it is humid or rainy since this can affect adhesion and lead to moisture pockets under the paint. If mornings are damp in your area, then painting should occur in the afternoon. If rain is expected or humidity it high, postpone exterior painting until conditions dry out.
5. Use a Paint With UV Protection
Another cause of alligatoring is sun exposure, particularly UV radiation. The UV light dries out the paint, causing it to shrink and crack. Concrete walls can hold a lot of thermal energy, which is why they can be prone to these cracks. Fortunately, there are paint formulations available that have built-in UV protection.
Contact a commercial painting service for more help.