A client of mine has an older (15 yrs+/-) stucco over wood framing house. The home is located in the ‘Northeastern’ portion of the USA. The stucco on the south and west sides have been cracking for years. As cracks have appeared he has had them fixed/filled. Can anyone provide information regarding a ‘permanent’ fix….’his painter’ is trying to convince him to paint with some sort of elastomeric paint but I think the ‘failure’ is deeper, either with framing movement due to thermal expansion/contraction or poor application of vapor barrier and/or stucco application. What can be done regarding exploring problem(s)? Water penetration? How can this be fixed or replaced? Thanks, Ray
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The answer is going to depend on which of the several types of "stucco" he has. "Older", in this case, would mean prior to about 1970 or so, when stucco was stucco. Since then a number of stucco-like finishes have come (and in some cases gone).
I grew up where a lot of homes were (old) stuccoed.
After a certain amount of time the stucco starts to deteriate.
So they came up with the elastomeric paint as a less exspensive way to "fix" the problem.
There are a lot of older homes with this probelm so it started a whole trade/service industry.
Since the probelm is on the south and west sides of the house I would guess it was sun related.
If it is real hot and the sun beats down on the stucco while it is curring, it can cause problems.
I've seen companies shade the stucco by hanging something on the outside of the scafolding.
Where I came from, in So Cal, the houses had plywood under the stucco for sheer stregnth. So structual is probably out. What's under the stucco?
In areas where stucco is used a lot the contractors know how to work with it. The crews do as well.
Maybe in the north east they did have enough exsperience.
I'm no expert. just some things I've seen.
Ray
As one of the posters here pointed out the south and west sides cracking point to the possible cause of the problem. Stucco is ridgid and assuming it is not an underlying structural issue ( position of cracks may give an indication a to whether or not this is the case) it is possible that the placement of control joints will aliveate the problem.
Ideally I'd place them vertically at window/ door openings, cut them with a diamond blade then caulk with a good polyurethane ( sikaflex or something similar ). Do this before attemting any remedial work to the existing cracks.
regards
Mark
Mark made a good point. I like control joints in materials that need them. They are overlooked a lot of the time.
But... ;^ ) I've seen large expanses of stucco with no control joints and no cracks.
Maybe it was a thicker, higher quality, more flexible stucco.
I don't know.
If I was putting stucco on a building I'd make sure it was done right because taking it off is a major pain.
rdon,
Can't tell without
rdon,
Can't tell without seeing.
Look for bad vapor barriors.
Wind driven water/moisture.
Most likely reasons are freeze thaw, structural movement, and bad stucco.
Freeze thaw tends to spall more than crack.
Structural cracks tend to be longer than lack of cure cracks, which tend to be spider webby.
Primary cause of bad stucco is not fully curing between scratch and brown coats.
Good stucco is kept damp for an absolute minimum of 7 days after scratch coat and after brown coat. Two weeks is better, but real careful pros cure them for 28 days.
South and west sides tell me that maybe those dried out too much for a good cure.
SamT
MS Excel for Contractors
To the OP (not sure if this is addressed to him or not).
No one can tell from here with out pictures.
Here in the North East water is the usual suspect. This being
the extreme beginning of spring you will soon have plenty of
opportunities to observe the walls in question.
Look for the wet area to coincide with the cracks.
Next as the loose stuff is removed for repair look for signs
of water penetration, vapor barrier situations etc.
I would venture to guess that if it had been a poor stucco application, it would have resulted in a more catastrophic
failure then such localized yearly cracking.
Could be structural, but then there should be other tell tale
signs in the building.
Look for the water.
I highly recommend reviewing the situation with a Conproco rep -
http://www.conproco.com/prodcolorguide.php
I've just finished a project with the Comprolastic - it's a really good coating product.
http://www.conproco.com/ConproLastic.htm
Jeff
Keep in mind that three coat stucco is pourous and while it sheds most water is not the water barrier--that's underneith. Sometimes too much focus is on hairline cracks. It's like a bathroom tile job--most water is shed by the tile and grout but the tile and grout are not stopping some moisture from passing through--they don't have to.
If you put a coating over the stucco you now trap any moisture that gets behind the stucco and can't evaporate out. You end up with the same issues that synthetic stucco has--if you do it you need to do it really well so no water can get behind. You also have now changed how the wall breathes--no longer can moisture that makes it's way into the wall pass through to the exterior--it is held in. If you have situations where the exterior gets cool the moisture will condense there and can't come out until it works it's way back into the house.
Yes the flexible coatings for stucco do work and expand and contract to keep cracks from reappearing, but in solving that mostly cosmetic issue there can be concequenses much more harmful to the house.