Prepare old stucco for paint?

Richard asked 10 years ago

I live in a old house with stucco exterior. Our house is in NW Kansas. The stucco is on top of a red clay block construction, I assume the house was built in the 30’s or 40’s I don’t know for sure.

What I need to know is how do I prep the surface of the stucco so that paint will stick to it without peeling after a year or two. I had an old timer tell me the use a lot of lime in stucco a along time ago and it requires special preparation before you can get paint to stick for any length of time. He didn’t seem to know what I needed to do. I was wondering if you could tell me what process I need to go threw to get paint to stick to my house.

1 Answers
Crowder Painting answered.

Preparation consists of a good washing with TSP, trisodium phosphate. This will neutralize any excess PH of the lime and produce a very clean surface. Make sure to rinse very well and rinse some more, the TSP will try to stick around in the cracks and pores of your stucco and this could mess with the primer.

Allow a couple of days to dry!

Now you need to use a good acrylic masonry primer. This primer can take the high PH of stucco. Apply a lot and make sure to back roll (if spraying) to fill in the pores. After priming caulk around windows and doors and any large cracks (anyplace water can get behind the primer/paint).

Now you can paint. I recommend an elastomeric but any good acrylic with a satin sheen will work. Buy your primer/paint from a real paint store not Home Depot or Lowes.