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Radon in expansion joints

695 Views 4 Replies 4 Participants Last post by  3onthetree
My basement has expansion joints on floor that I can see gravel with a flashlight so guess radon is coming in this way mostly. Before I put in a radon fan what’s the best way to seal these joints up. Asking because I have a lot of joints to seal. Thank you


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interesting as rare to see 'expansion' joints in an area where conc dimension's stable,,, what's the ambient radon reading ? typically you'd use closed cell backer rod & (polyurethane/silicone/polysulfide) concrete sealant,,, much cheaper to install air exchanger on timer than radon system
My radon readings are like 14 to 15, noticed the expansion joints need to be sealed up then plan on installing a radon fan in the sump so hopefully radon readings will go down. First I thought sealing with cement but that will crack so will try a backer rod and tube sealer.
After much research this is the product that I chose to use for sealing the crack between the concrete slab and foundation in our basement as part of our radon mitigation project.

The interior field of a basement should have "control" joints rather than "expansion" joints. Goodness, that looks like a seismic fault, not a control joint.
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