Salitre is a fact of life in the tropics. When we moved here we had very little idea what it takes to deal with salitre in a climate like ours.
What is it? It is the powdery stain that leaches through the paint – basically salts moving out of the mortar and concrete through moisture. Sometimes the moisture is coming from a leak – and sometimes it is from the humidity, rain, or groundwater seeping up.
- This patch isn’t too bad. It is much more obvious on dark colors.
If you move to the tropics and think that the only time you are going to need to paint is when you’re redecorating, you’ll have a bit of a surprise in store for you! I’m sure new construction has less, but it is just a part of life for everyone here.
- Salitre is called “wall cancer” for a reason.
For example, four years ago we bought our house and had the entire house painted. It had some existing salitre and unfortunately since we were newbies we didn’t make sure the painter followed proper salitre protocol. (He said he did, but…) Within months salitre was visible again in a few places. What did we do? What most people do here. We ignored it or put a cabinet in front of it, of course!
- I think there was some kind of painted border in this room at one time. This room had a patch of visible salitre about 1 foot by 4 feet…. but when the painters started scraping, what a mess! Henry is checking out the dusty floor.
But after two years we couldn’t ignore it any more. Out came the paintbrushes and salitre repair kit! Here’s what you do:
- Scrape the area with a spatula until you are not able to remove any more paint.
- Paint the area with muriatic acid, taking care to not put your nose too close. Wear gloves!
- Let it dry
- Wash the area with water to remove the acid
- Let it dry
- Paint with sealer
- Paint with paint
It’s kind of a hassle but pretty important. We have professional painters here now, and their procedure is a bit different. They scrape the area down entirely and then they sand, patch with their special mix, seal the entire room with sealer, and then paint.
We’re having the exterior and the living room, dining room, and stairway painted right now, four years after the last full paint job. It’s going to look beautiful. But I’m under no illusions that we’ll get more than four years out of this paint job just because it’s such a fine job. In México, I think there should be a saying that “Nothing is certain but death, taxes, and salitre.”