Expert: Dan Griffin - 4/8/2011

Question
Hi Dan,

I have a couple of questions about our basement. We would like to renovate the basement (which is currently unfinished). We seem to have some cracks in the poured concrete walls (house was built in 1985)- we have seen water come in although not more than maybe 20 cups of water, during a very bad downpour of rain. Our neighbour recently sold her house and found out during inspection that most of the homes in this neighbourhood suffer from poor "shearing", and that the ballpark to have this fixed is $5000. My questions are:

1/ what is shearing (so we can see if we also have this) and how much does it cost to fix? imprint of our house is approx. 1200 sq feet per floor, (2500 sq feet total for 2 floors above ground level).

2/ for the cracks in the walls, what do we need to do to fix these, the water only seeps through at the bottom and like I said, there is not a lot of water coming in.

3/ what should we look for in someone quoting to finish our basement - I don't know how we will know they are giving us a fair price.

Thanks so much Dan, hope you have a nice Friday.
Tracy.

Answer
Tracy, I would NOT finish a basement that had any signs of water infiltration.  YOu need to spend your money on fixing the water condition first.  The very most common reason for water problems are exterior grading problems.  You may have a low area on the outside, poor drainage of rainwater, downspouts dumping water too close to the foundation, flower beds, bushes, and plantings along the building face (my #1 personal pet peeve).  I suspect that this is your prime problem.

I do not understand the term shearing, it must be a local Canadian reference.  A shear wall is one designed to prevent a building from racking in a seismic or extreme wind event.  I cannot see how this could be attributed to a neighborhood.  Soils have a shear strength, meaning that they either slide or interlock more or less depending on their type.  The Leaning Tower of Pisa would be an excellent example of poor shearing strength of soil.

The only correct way to truly cure a leaking wall is on the outside.  This would require digging and cleaning the exterior, applying the proper water proofing, having or installing proper French drainage that goes to daylight or sump.

Make sure that any new construction can breathe.  Carpet and tile can trap water.  Use rigid foam insulation, NOT fiberglass.  Allow an air space between stud wall and exterior wall.  Any contractor that you consider should have verifiable basement work references.

I know I haven't answered any of your questions completely, but if you have more specific questions, please ask again.