Q: I have narrowed a leak in my stucco wall to the lower corners of a window. Below it, I had a small firewood pass-through door removed. I’ve watched various other stucco repairs on our house, and I’m pretty handy, so I have a pretty good idea of what I need to do, but I have a few questions:
1. Once I remove the stucco, what caulk, tar or sealer should I use to cover small holes or leaks?
2. Besides Stucco Patch, is there a bag mix of stucco cement with the right proportions of Portland Cement, sand and lime that I can simply purchase?
3. I know it’s probably a good idea, but do I need to use cement adhesive on the prepared edge of the existing stucco for my scratch and brown coats?
4. Previous repairs were made up of three coats: scratch, brown and dashing. The brown coat contained the Mission-style trowel marks but otherwise had a relatively smooth finish. Once dried, the dashing was done with a hopper gun and contained the color. It left a rough, sort of large pimply finish. Was the material used in the dashing just more of the same stucco cement?
A: First, we suggest you check out the top of the window. The small leak could be migrating from the top of the window to the lower corners.
We assume the plan is to remove the stucco from the affected areas and attack the source of the leak. If that is the course of action, we recommend that you repair any damage you do to the building paper by inserting building paper patches in slits you cut above the damaged section, letting the patch come over the hole. Glue the patch down with roofing mastic so that it’s watertight. Roofing mastic comes in tubes that fit a caulking gun to make application neat and easy.
Wherever you open the area where the window meets the siding, run a bead of caulking along the edge of the window. If you don’t remove the stucco down to the siding, at least run a bead of caulk at the top edge of the window to inhibit any leakage that might be occurring at this area.
A silicon latex caulk is the ticket for this job. There is packaged stucco mix available at hardware stores and home centers. But a 50- to 100-pound sack of stucco is much more than you’ll need. That’s why we recommend “stucco patch” for small jobs. It’s pretty much the same stuff, just packaged in smaller quantities.
You don’t absolutely have to add Portland Cement to the mix, but we recommend it. The additional cement helps the stucco stick to the trowel and to the wall.
The dashing, as you call it, is what we know as splatter texture. Whatever the name, the finish is the same material as the other stucco coats — thinned down to a slurry. For a job this small, a hopper gun is a waste of time and material. To get a similar finish, mix the slurry in a bucket to thick-soup consistency. Dip a stiff bristle brush in the slurry and, using a flick of the wrist, direct a spray of the slurry on the wall. Do this several times until the proper texture appears. To get the flat spots, wait a few minutes for the slurry to set up and lay it off with a trowel or wide-blade drywall knife.
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