One or two dimple mat/basement questions
I posted last week but didn’t get much of a response and could still use some guidance on a few questions.
I am finishing the basement of my Philadelphia row house and have a few questions about insulating it. In typical row house fashion, the basement is very long (two common walls, each about 50′) and not very wide (two exterior walls, each about 11′).
We recently had a French drain installed on one of the two 50′ common walls (the lower of the two). The contractors installed a dimple mat above the French drain, but it only rises about six inches above the ground–the rest of the wall is uncovered. Note: The basement has never flooded above the 6″ mat. The most flooding we ever had was about 2″ in one corner of the basement, but that was before installing the French drain
1) Should I extend the dimple mat up to grade (about six feet above the slab) on the wall with the French drain? Or is the six inches of dimple mat I have currently sufficient? Should I add dimple mats to the walls that don’t have any?
2) I have seen some basement flooring systems that make use of dimple mats, rigid foam, and plywood as subflooring. I was thinking it might be easiest (and most mold-resistant) simply to tile over the existing concrete slab. Is there any problem with this idea? Is there any need for dimple mats or other subflooring underneath the tile?
Thanks very much for your help!
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