Walkout basement shower assembly
We’re in the process of completely redoing the walk out basement of a 1940’s house. The old slab has been removed and we’re going back with 4″ of gravel, 2″ of EPS, vapor barrier, and a heated 4″ slab. The location for the new shower has us a bit stumped…
At some point, the basement was added by digging out. So, we’ve got the original poured foundation wall (front elevation) to about 5′ below grade terminating at a 2″ slab creating a crawlspace floor. The crawlspace then steps down, with a CMU retaining wall, to about 8.5′ below grade.
The side walls step down four times to the daylight back of the house. These sidewalls become half brick, half framing where the crawlspace steps down. It is in one of these corners that we intend to build a shower. So, the shower will have 39″ of masonry topped by 5′ framed wall. The question is, how do we build this shower?
Proposed: 3/4″ Kerdi board adhered directly to masonry to serve as both insulation and tile backer. Rockwool in stud bays above grade fronted by kerdi. Will this work? Is kerdi a vapor barrier that will trap moisture in the rockwool? If moisture travels through the masonry walls, will kerdi protect the tile/grout? Thank you in advance for your help.
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