OK material to patch and prime cracked unpainted exterior stucco?

[Muse]

Should have done this soon after the tear/off roof replacement, but better late than never. It rarely freezes here and if it does it's never when it rains. However, I was told by the roofer that I should prime the stucco they applied when they did the roof job, this was ~8 years ago.

The cracks in the stucco, are AFAIK, not many and extensive. There are some.

I am having my garage reroofed, and the new roofer noted my unprimed stucco and said I should patch the cracks and prime.

I have plenty of these two primers to choose from in my workroom:

1. Kilz2 water based primer
2. Zinsser Cover-Stain oil based Primer Sealer Stain-Killer Bond Coat

Which of those primers to use?

Before applying the primer, I have my choice (unless I buy something else) of one of these, of which I have unopened quart cans:

1. MH Ready Patch
Professional Formula Spackling and Patching Compound INTERIOR / EXTERIOR

2. DAP CrackSHOT High Performance Spackling Paste

3. EVERCOAT Home Fix Super Strength Universal Repair Filler
2 part, "Sands in 30 minutes"

Which of those fillers to use?

 

[herm0016]

None of them. None of them are flexible enough for stucco. We use log chinking and it works well, made to stick to uneven surfaces and has texture like the stucco. Some of it is also semi-permiable. Use a good elastomer paint over the whole thing to seal it. The whole house should probably be painted. Stucco needs to be sealed, that's why it cracked.

 

[Muse]

None of them. None of them are flexible enough for stucco. We use log chinking and it works well, made to stick to uneven surfaces and has texture like the stucco. Some of it is also semi-permiable. Use a good elastomer paint over the whole thing to seal it. The whole house should probably be painted. Stucco needs to be sealed, that's why it cracked.

Thanks! Glad I asked!

The "good elastomer paint" is, I assume, just to act as a primer? Then, paint the whole thing, the whole house included, right?

Where do I get log chinking? Hadn't heard of it before, have never seen any. A search for log chinking at homedepot.com comes up empty.

 

[herm0016]

Not sure where you are, most of the building supply places around here have it, be we are in the Rockies so lots of log homes. The elastomer paint is all you need, it's like a rubber membrane for your house.

 

[Muse]

Not sure where you are, most of the building supply places around here have it, be we are in the Rockies so lots of log homes. The elastomer paint is all you need, it's like a rubber membrane for your house.

I'm in Berkeley, CA. Bay Area weather. Seldom freezes, when it does it's dry weather, not rainy, and I've never seen a flake of snow here, we're talking 50 years. Lowest temperature I've experienced right here where I am (there's lots of microclimates around here) is 26 F, but it was dry.

I don't think there's much in the way of log homes around here, I've never heard of any. I think I may have to order log chinking, don't know if I'll find any in local stores.

So, the elastomer paint, I don't prime the stucco at all, just put elastomer paint on it? Can I paint over the elastomer paint if I'm later painting the whole house? IOW, with something different?

 

[homebrew2ny]

Agree on the elastomer paint. However it is a paint and can be tinted to just about any color as well. So it can be color matched to the house paint as well.

And correct, no primer required.

 

[Humpy]

Before using elastomeric paint on your house I'd research a little about how water is intended to be shed from stucco walls and the future maintenance requirements of painted stucco before making the decision. Cementitious stucco is brittle and will crack from movement of the structure or because of too much/quick evaporation of water when it was applied. A water barrier and flashing is typically installed behind stucco do deal with any moisture intrusion through small cracks. Adding a second water barrier can potentially cause problems.

Rather than solving technical issues, aesthetics and maintenance drive the decisions. Where I live stucco is almost never painted, a coat of colored stucco is applied that will last for several decades. The few people who paint are trapped in the maintenance cycle that comes with it.

 

[herm0016]

Around here it is all painted. It was 70 5 days ago, then we had 6 inches of snow last Thursday, and its 70 again today. I help maintain a house that is 100% stucco at about 8k feet elevation, adobe style with a flat roof and parapet walls.

 

[Humpy]

Around here it is all painted. It was 70 5 days ago, then we had 6 inches of snow last Thursday, and its 70 again today. I help maintain a house that is 100% stucco at about 8k feet elevation, adobe style with a flat roof and parapet walls.

It's interesting how varied local practices can be. Santa Fe NM is a similar environment to yours and stucco is rarely painted, hotter places farther south the sun destroys paint in a few years. I think in CA it's usually painted. I wonder if it's as simple as the ratio of painting to stucco contractors dictates what gets painted and what doesn't.

My feeling is too avoid painting anything outside so you don't have to scrape/sand/prep and repaint in the future. On the other hand painting is fairly quick and inexpensive and looks good while it lasts.

 

[herm0016]

it is interesting. The elastic paint used on ours was not redone for some time, it faded a LOT but did not peal. it did however become permeable and let in a lot of water that rotted out a wall and some other spots, and lots of cracking. it was all patched up and painted this year and looks nearly brand new. the house is maybe 25 years old? I have only been around it for the last 4 or so. colder and wetter up here, nearly double the precip and 4 to 5x the snow.

I also try to avoid film finishes outside, but never even thought about it for stucco.