Filling Gap Between Stucco Siding and Mudsill
drakewald
| Posted in General Questions on
Hello,
I’m remodeling my kitchen due to a dishwasher leak that became a serious mold situation. It’s slab foundation, 2 x 4 walls, paper, stucco exterior (no sheathing). I don’t plan to insulate because I’ve only got portions of the drywall removed. I was planning to put down some canned foam to reduce the ways bugs get in.
However, after reading a few articles and responses here regarding stucco and the need for airflow, I’m not sure I should do this. In several spots, I can see daylight between the paper/stucco and the sill plate. What’s the best way to fill these?
Thank you!
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Replies
Drake,
It's possible the wood or metal lath was nailed directly to the studs. So the empty wall cavity plays a critical role in promoting drainage (when water gets behind the stucco). If that is what you have, then you don't want to seal the gap at the bottom of the wall assembly.
You might want to post a few photos and see if a GBA expert can advise you.
Hi Drake,
Your hesitation is warranted. With a reservoir cladding like stucco, you want to ensure bulk-water drainage as well as drying potential. Here is a post about rainscreens for different cladding systems by Michael Maines. He talks about how to address your concern around insect pests.
Thank you Steve and Kiley. I don't have a paid GBA membership, so I wasn't able to read the pertinent information from the article. I have attached photos, I'm hoping they help provide a solution to keep insects out but keep the air circulation sufficient to dry the stucco out.
Drake,
You could spread borate insecticide powder inside the opening before sealing it up. You could also treat the exterior to discourage unwanted visitors.
Thanks Steve. My pest company treats outside and they recommended diatomaceous earth in each stud bay and under the toe-kicks too. I guess I'll just do that and leave the air gaps open. Thanks for you help!
Hi,
You can seal between the grade D stucco paper and the mud sill with caulking. A polyurethane sealant will stick to the paper. The drainage plane is on the outside of the paper against the back of the stucco. No on the inside of the wall.