Description of the typical radon entry routes in concrete block foundation walls

Soil gas containing radon can enter a house any place it finds an opening where the house is in contact with the ground. In this image potential entry routes for radon in homes with concrete block wall foundations are show. The radon entry routes shown in this image include; unclosed voids at the top of exterior walls, unclosed voids at the top of interior block walls which penetrate the floor slab, missing mortar between blocks, cracks through the blocks or along mortar joints, floor/wall joints, and pores in the face of blocks.