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I am preparing to finish out my basement, which is fully exposed on one end, fully below grade on the opposite end, and partial below grade/daylight on the two sides.  The floor and walls are poured concrete - 4 inch thick floor, 6 inch thick walls.


The floor slab and walls have hairline cracks in them.  Most of the cracks have no moisture entering, though one of the wall cracks has a small bit of moisture entering at times (very seldom, but it does at times).  Do I need to seal/repair all the cracks, or just the one with moisture problem?  Please explain what/how to seal it.

None of the slab cracks leak.  Do they need patched?  Is there a product I can pour into the cracks to "weld" the concrete together?   I’d like to bond the cracks to prevent them from possibly becoming larger.

I also have some leaking (again seldom, but it does at times) where the exterior concrete walls (6 inch poured concrete) attach to the floor slab (floor slab was poured first, then walls formed and poured directly on top of the floor slab).  How can I seal this floor-to-wall joint?  Is there a pourable sealer/bonding product that will flow into this seam and seal/bond it against moisture?


I understand that moisture can pass through the pores of the concrete, and could create mold/mildew problems.  I see none of that (moisture through the pores, or mold/mildew) occurring in my basement.  However, I don't want to have moisture/mold/mildew problems develop some years latter behind the drywall walls I plan to install against the existing concrete walls.   Is there a good moisture barrier/sealer I can paint on the floor and walls as a safety measure against this possible problem?


And lastly, radon gas is becoming a big issue.  Any products recommended to seal the basement floor and walls against radon gas?


 Thank you for your help.
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Posted 2016-09-28T15:59:04+0000  by JakeItaly JakeItaly

Hello JakeItaly, and welcome to the community!

Sounds like you have many things going on, you might want to consider calling in a professional basement waterproofing and foundation repair company, they will give you the best options and have the most experience.

Your other concern, Radon, if you have been tested by a licensed contractor, they will likely tell you the level of radon in your home and what to do about it. In some cases, I have seen professionals drill a hole somewhere in the basement floor and insert PVC with a fan to exhaust the radon gas, I'm not familiar with a seal-type material not it's effectiveness, again this is where a pro with experience can assist. You can get a few estimates and check with the Better Business Bureau, hopefully that will help narrow down the contractor.


Posted 2016-09-29T15:52:37+0000  by Angelo_HD_CHI
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