I have a fieldstone foundation in my 1888 Victorian that is in pretty good shape for it’s age. Basement virtually never lets in water (only once and that problem is fixed by routing downspouts into a new drain). I’m considering finishing some of the basement space and have some questions…
(1) Should I use any type of waterproofing sealant on the stone/mortar before putting up a stud wall.
(2) In old houses such as mine, how far below the basement slab does the foundation typically go ? I’ve thought about excavating 6-12 inches or so and pouring a new concrete slab to get more headroom and a more level floor. Anything I should be aware of (I don’t want to risk undermining the foundation)
(3) I’m concerned that putting a vapor barrier behind a stud wall will ‘trap’ moist air between the finish wall and the foundation, causing the ‘equilibrium’ of the old wall to fail and making it break down. Is that valid ?
Any general thoughts, observations or experiences would be most appreciated.
Thanks,
Robert.
Replies
I use Thoroseal on foundation walls prior to finishing a basement whether there is an existing moisture problem or not.
Old houses, new houses...there is no typical when it comes to foundation depth in relation to slab depth. The foundation should have been built below the frost line....I stress should, but that is not always the case. The slab was poured at a depth determined by architect specifications and / or existing conditions. As long as digging down to lower your floor does not bring you below the foundation footings, you are in no danger of undermining.
The water proof sealent you use (Thoroseal) will act as vapor barrier making poly unecessary.
J. D. Reynolds
Home Improvements
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