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Crack injection vs dimpled membrane?

2K views 12 replies 5 participants last post by  gizzygone 
#1 ·
Hello all,

I'm in a bit of a bind: we're about to start the process of finishing our basement (poured concrete foundation). It currently has a crack a that leaks a trickle of water during severe storms.

We have a company coming next week to seal the crack. Yesterday, however, we had a nice storm drop 3" of rain down, which revealed several concrete ties that were also leaky (nothing accumulating on the ground, but the dampness was obvious.

I can improve exterior grading to an extent, and the gutters already flow away from the house.

I'm tempted to install a dimpled membrane and drain it under the slab: it seems like a ton of work, but it seems like a nice insurance policy short of digging up the foundation and fixing the exterior.

What are the thoughts here? Is that necessary? Or would fixing the tie leaks be enough?

I was planning on using closed cell spray foam as well...not sure if that is compatible with the membrane, or if the foam will provide water barrier itself.

Another idea was putting small weep holes into the slab, applying spray foam insulation; and installing a sump pump? (There's about 8" of gravel under the slab)
 
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#5 ·
It seems most of the waterproofing companies in our area use this particular technique, and charge an arm and a leg for the labor involved.

Essentially, you break up concrete around the perimeter of the floor, and dig down next to the footing. You add a perforated pipe, and slope it towards a simp pit.

You back fill with gravel, then apply what is essentially a thick piece of plastic with dimples on it over the gravel, and up the concrete walls, securing it at the top. You apply concrete over the plastic to finish the floor portion.

Basically, the idea is whatever water enters the foundation is directed below the slab, and pumped out. It almost acts as a band-aid protecting the wood.

I don't get tons of water now: maybe the equivalent of a small bottle of water spilled, but it's still enough to wick up into any studs.
 
#4 ·
I agree, that would be ideal, but it's so cost prohibitive at this point, I'm not sure we could do it: with gas, water and sewer lines entering the building its difficult to use mashinery to get the work done.

Plus, it would require new landscaping, new concrete (walkways), etc.
 
#10 ·
' an arm and a leg ' is fair otherwise we wtrproofers would all have small boats :laughing: we do this work every week :thumbsup:

for what the op described, i'd suggest injection w/hydrophyllic polyurethane but realize injection's more of an art than a science :yes: still & all, a competent diy'er can successfully do it,,, emecole's got good materials, they're diy friendly, + love to talk you thru problems.

in general, its more labor-intensive AND costly to excavate & waterproof :furious:
 
#12 ·
Here's my dilemma: I have a guy coming to repair and re-inject a leaky crack tuesday already. Prior to this massive rain-storm, it was the only source of water entry. I'd be more than willing to have him inject the leaky ties that appeared, but I'm afraid of what happens when we get a 4"rain storm? Will it seep water in other places???


The epoxy I'll trust to the pros with the tools. If I'm putting up a plastic membrane: I'll rent a 70lb hammer, and do the grunt work to save $5000
 
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