Make an Inspection
Check the concrete slab floor for cracks, holes, openings around pipes and other intrusions.
Inspect the French drain for a gap between the walls and the slab.
Determine whether the sump pump is a radon-sealed pump.
Check the sump for gaps around the pump.
Clean and dry the areas to be sealed with a vacuum cleaner or oil-less compressed air.
Prime the areas to be sealed with Radon Crack-Weld or similar product.
Fill the cracks, holes and gaps with dry sand.
Soak the sand with Crack-Weld.
Replace non-radon sealed sump pump with a radon-sealed pump.
Install and seal a cove base over the sealed French drain.
Seal off existing cove bases and all pipe intrusions and wire chases with Pipe-Tite or similar sealant.