During this past summer after ripping up my deck I noticed that the stucco from my foundation to about 2’ up is starting to buckle out and crumble. After deciding to grind about 3’ up and remove the damaged stucco I noticed that the OSB behind it was also buckling out. The OSB sits directly over top of the foundation. I’m guessing that there was no expansion joints in between the sheets to allow for that little bit of expansion. My plan is to cut the OSB 3’ up and replace with pressure treated plywood. I’m wanting to rebuild my deck but also need to figure out a way to somewhat damp proof that lower section of plywood before I do. And to prevent water penetration in between the top of the foundation and the underside of the plywood. My house was built in 1920 so the foundation sits directly on grade with a crawl space inside it.
thanks!
Replies
1920’s house? OSB?
Yes, I bought the house 4 years ago. I’m assuming before they redid the exterior face of the home they either removed the original ship lap or went over it with OSB.
Lots of problems with stucco over any wood, not just OSB. Not to disparage the helpful advice here on FH but it is a very complex topic. Wood expands and contracts but the stucco doesn't... I don't know where you live, but it is made even more complex due to freeze/thaw cycles. There could be more problems with your stucco that you just haven't found yet. For this small area, you might consider concrete board like that used behind the tiling of showers and bathtubs.--but that is only a thought that came to mind while writing this and with research might not be suitable. Good luck.
What was the WRB between the stucco and OSB? If you're on instagram, @buildingsciencefightclub just had a great post about stucco assemblies.