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Basement interior plaster or stucco over a drainage mat

Jason Advani | Posted in General Questions on


   I have a poured 8″ concrete basement wall in Zone 5A that is currently stable but is way out of plumb and I need to finish it. It’s about 10′ wide. I cannot afford the space to fur it out, insulate, and finish the wall. I’m out about 3/8″ at the midpoint of the wall (4′ AFF) and 1-1/2″ at the floor.

   Basement has interior drain tile w/ dimpled plastic drainage mat stubbed up 6″ AFF at the wall. I want to incorporate the ability for any moisture that comes through the wall (and there are signs of past intrusion) to drain to the interior drain tile. This rules out plastering/stuccoing the wall directly.

   So, I plan on placing a drainage mat of some material directly against the wall and tucking it into the existing stub up of drainage mat. That mat could be one or two laters of 15# or 30# felt, polyethelyne, a WRB, Tyvek, something else?  Then I would attach diamond mesh (or similar) to the wall and I could stucco or plaster that and build up the wall towards the bottom to be plumb. I know that towards the top, I’d be a little thin.

   Question is, what type of mat to install on the wall? Also, is plaster okay to use as the finished surface or am I better with stucco as it is more moisture resistant? Either surface would need to be able to handle latex paint.

   I happen to have some Structo-Lite on-hand but it’s warning against moisture is worrisome. I’m slightly concerned about where the dewpoint in the wall would fall because I wouldn’t want it inside the plaster or stucco unless it was totally impervious to water.

   Oh, the drain tile is connected to a radon mitigation system so I have to seal it up to the existing dimple mat stub up such that it’s airtight (as much as possible). I do not want to simply suck conditioned air out of the building. That suction could also help attract moisture from the building and pull it into a permiable finish material….

   Seems very complicated in my mind. What are your thoughts?


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