I constructed a custom home on a hillside site. There are many block with stucco finish retaining walls . Question: Why are the outlines of the block “bleeding” through the surface ? Is this a painting problem or a stucco problem ? Your comments are most welcome and very much appreciated. Thanks.
Sandy
S & W Builders
Replies
How long did you let the stucco cure before painting, and what kind of primer did you use?
" If you kill a man, it is a tragedy. If you kill a million, it is a statistic." - Josepf Stalin, attributed.
Ah, a good question for me to have answered. I need to paint
a newly stuccoed block wall. How long do I wait before painting?
Is a masonry/stucco paint better than a good grade exterior
paint (my wall is a sand finish)? Is there any primer/sealer
used before the paint?
ANY help in this process GREATLY appreciated.
glenn
Unless there is some reason why you have to paint stucco, don't. You will be sorry in the long run (or someone will). Taken over a period of years, it is almost always less expensive and in every case a better quality job to apply a new color coat.
I fight with this all the time. It's the old "good, fast, cheap" triangle.
DRC
My thought process was along the lines of - masonry needs time to cure. Stucco can act much like plaster, depending on what the mix was and a multitude of other factors. The suction mentioned, in my mind at least, has more to do with the stucco sticking to the wall and how much moisture the block is pulling from it. But if you have high suction and don't compensate, you can have a chemical reaction going on slowly and just waiting for more moisture to make it start running again. Add your average latex paint, and you burn. I'd let anything portland cure a good 30 days before painting, and use a masonry primer. I'm still a rookie at plaster stuff, but that's where the gears were leading me." If you kill a man, it is a tragedy. If you kill a million, it is a statistic." - Josepf Stalin, attributed.
RW, My sub wanted to paint the walls 48 hrs after the stucco was applied. I insisted on 14 days based on the recommendation that I received from the paint supplier. I will insist on a primer and waiting 30 days the next time. Thanks
Hi RW , Checking my records and memory, it was 15 to 18 days.
Sandy,
If you are seeing the outlines of the mortar joints it is because the stucco cures differently over mortar than block. I've always heard it called capillary action or suction, I don't know if those terms are correct, but they do indeed describe what's happening.
DRC
Dave, You are probably correct. What's got me baffled is that some parts of the wall are fine but other parts show the outline. Thanks
Like many have already said, this is called "ghosting" and generally means that the stucco thickness is not what it should be. Having said that, it will probably be fine once painted. Doing it right costs more for the mason or plaster since a day wait is required between base and finish coats.
Wait as long as you can to paint.
MHINSHAW, Thanks very much for your input. I think you hit the nail on the head .
Sandy