What are common problems with stucco?
Saturday, January 18, 2020
There are three kinds of wall finishes that are commonly called “stucco,” and each has its own particular issues. To know how to tell the difference, go to our blog post Do stucco walls mean a house is concrete block?
1) Stucco over wood frame - When a house is wood-stud frame, the stucco is applied in three coats over expanded wire mesh which is separated from the wall sheathing by a moisture barrier—typically Tyvek or a similar material, or roofing felt. This is also called hard-coat stucco. Because the wood wall framing and the stucco have different rates of expansion/contraction, the stucco must be properly installed with expansion joints and correct flashings to accomodate it. When not installed correctly, any cracks let moisture into the wood framing and rot follows. See our blog post Why is my stucco cracking? for more on this.
2) EIFS (Exterior Insulated Finishing System) - Also called synthetic stucco, it is essentially a foamboard and fiberglass mesh attached to wall sheathing that is covered with a polymer-based material, and then textured to look like stucco. It is an alternative to hard-coat stucco. Go to our blog post What is the difference between EIFS and stucco? for more info on the materials and the recurring problems it has.
3) Stucco over concrete block - This is the most stable type of stucco and least likely to have a problem. All stucco finishes will develop fine cracks over time, but the underlying concrete block can absorb and disspate minor moisture intrusion without damage to the structure. Adhesion issues may occur if the stucco is not applied in the three required coats and at the correct thickness. Cracks should be be repaired and openings at windows and doors caulked on a regular schedule.
All three types of stucco will crack when the house is experiencing structural movement due to foundation problems or a sinkhole. If you are experiencing more than minor cracking in your stucoo, we suggest reading How can I tell if a crack in a stucco wall is a structural problem and what is causing it? and What are the warning signs of a sinkhole?
By the way, stucco is also applied over solid-concrete wall houses, like the one shown below, and has a similar low level of problems to concrete block.
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Here’s links to a collection of some of our other blog posts about STUCCO:
How To Look At A House
McGarry and Madsen's home inspection blog for buyers of
site-built, mobile/manfuactured and modular homes
for Links to Collections
of Blog Posts