Waterproofing Limestone Basement Walls
I am finishing a limestone foundation wall + concrete slab basement with moisture issues. This is a 100+ year old house with no vapor barrier, waterproofing, or exterior insulation. Exterior grading is in good shape.
Before posting this question, I’ve tried to glean all I can from these great articles and comment threads linked at the bottom of this post.
1) Install exterior gutters
2) Install interior French Drain system and sump pump per Hammer & Hand details…only variation being the dimple matt only extends 4″ up foundation wall. Sprayfoam is applied directly to wall (per Martin Holiday) rather than on top of a full-wall dimple matt.
3) Finish floor with the following: 10 mill poly taped to foundation wall poly/dimple matt, 1″ depth self-leveling subfloor, 2″ EPS, plywood, LVP
Q1) Poly v. Dimple Board vs. Only Spray Foam on walls: With a limestone foundation wall, my waterproofing contractor is telling me it would be better to apply the closed cell spray foam over the top of a dimple drainage mat or poly. The thought being that the dimple matt/poly will provide a surface /path for the water to drain down and over to the drain tile system.
@Martin Holiday – in several places, you’ve said that poly is fine, but unecessary and that its fine to apply closed cell sprayfoam directly to the foundation wall. Wouldn’t that prevent the water in the limestone from draining down to the drain tile? If the water is trapped in the limestone / not finding its way to the drain system, won’t that degrade the limestone/structural integrity of the foundation over time?
Q2) PVC vs. Corrugated Perforated: It seems like most images of drain tile systems on GBA and the Hammer & Hand spec all use perforated PVC pipe. Corrugated Perforated seems to be the standard industry go-to and a lot less expensive. Internet abounds with claims and counter claims about which drains better, clogs less, etc. Any community opinions?
Q3) River Rock vs. Crushed Stone: Smooth, washed river rock appears in most GBA pictures and is recommended elsewhere on the internet. But H&H specifies clean crushed stone. Any community opinions on what drains best and is least likely to result in clogging?
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