STUCCO NEWS.NET

We just had a masonry stucco application put on our home in the last 3-4 months and have noticed a large amount of cracks in the stucco. I have heard over time you might get a crack or two due to settling, but the job has essentially just been completed. Is this normal, or does it sound like an inferior installation that needs to be redone. Several comments by uninvolved third parties (with knowledge) have commented that it shouldn't be that way, but the contractor (who would be liable) says that it is just the way stucco is. We are thinking of paying for an independent opinion.

Some cracking is normal, particularly on wood framing. Even if everything is done the best as possible. We used to get a lot of cracks on our jobs and I have learned to reduce the cracking to very few or none. Here's what I think is going on, and a possible solution.

By now, I hope you have seen my 12 point list for reducing cracks in cement stucco. You can download a pdf file here: I even added a 13th point here:

Even though I haven't seen this job, here is what I think. The most common problem is not letting the basecoat cure before putting on the finish. It is a good idea to let the brown coat set up for a week before applying the finish. The brown coat will shrink and crack. Even a small amount of cracking in the brown coat will create a lot of cracks in the finish. If this is the case, the wall can be recoated using an acrylic bonding admixture in the new finish. If you have visited my site before, we mix the bonding admixture half and half with water and mix mortar with this mix instead of pure water. Not only is the bonding admixture necessary for bonding, the flexibility can reduce cracking. Note a bonding admixture is one of my points. Not only does the admixture add flexibility to the mortar, but eliminates shrinkage cracks in the finish coat material.

Another frequent source of excessive cracking is water infiltration from lack of flashing or drip edges, leaking window installation, etc. Flashing and window installation can be corrected by chopping off the stucco and correcting the flashing but this requires a patch and recoating the wall.

Another main reason for excessive cracking, or two reasons is the sand is too fine in the finish coat or too much lime in the finish coat. The finish coat sand should be a little coarse and sharp. Most factory premixed finishes have way too much lime. Lime shrinks and also weakens portland cement mortar. We add a maximum of one fourth bag, that is a 50 pound bag of lime to one bag of portland. Fine sand also weakens the mix and increases shrinkage. Too fine sand also makes the mortar set too fast, usually requiring retempering, which also weakens the mortar and increases shrinkage.

I can do consulting and advise on these crack issues. If someone sends pictures, I usually charge between free and $ 200. You can't find anybody cheaper.