Coordinate radon sub-slab depressurization with foundation waterproofing/crack sealing

Steps

1. Recognize these are related but distinct systems: sub-slab depressurization (SSD) reduces radon by creating negative pressure under the slab so soil gas is exhausted outdoors; waterproofing/dampproofing and crack sealing reduce bulk water and moisture intrusion — coordinate rather than substitute one for the other.
2. EPA guidance is explicit that sealing cracks/openings alone is not a reliable stand-alone radon reduction method — it's a supplementary step alongside SSD, not a substitute for it, so don't spec crack sealing as a radon fix by itself.
3. Sequence physically: install the SSD suction pit and sub-membrane piping before or during under-slab vapor barrier work so the ASTM E1745 vapor retarder is sealed around the radon pipe penetration rather than retrofitted around it later.
4. Treat waterproofing's soil-moisture reduction as a secondary radon benefit, not a design basis for skipping SSD in a radon-prone area — drier soil can slow soil-gas movement but doesn't substitute for active depressurization.
5. Detail all shared foundation penetrations (radon vent, sump lid gasket, floor drain) on both trades' drawings so sealing and venting details don't conflict.