[Anglib56789#]

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

 

[stadry]

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

 

[Anglib56789#]

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.

 

[Chris616]

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.

https://www.dap.com/dap-products-ph/dap-30-self-leveling-concrete-masonry-high-performance-sealant/

Chris

 

[3onthetree]

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.