2 ms·

> 1/2 of the basement is carpeted and drywalled Realistically, popping a hole in the slab and installing a fan might be less disruptive than tearing out all t

> 1/2 of the basement is carpeted and drywalled Realistically, popping a hole in the slab and installing a fan might be less disruptive than tearing out all the finishing. Do you have a sump? First, seal it. Caulk as much of the wall-floor joint as you can. If it's still not low enough, add a fan _to the sump cover_, since the weep-tile system might provide all the sub-slab vapor communication you need without adding any new holes.

deskamess 4y ago
Can radon come in through the walls? We recently got a crack in the basement wall and a small water leak. Will be fixing the leak next spring, but I am curious if this is a cause for higher readings. The long term average is about 135 but it occasionally spikes to 200+. Also in Canada.
- myself248 4y ago
  Technically yes. It's a gas, so it'll permeate through anything that's gas-permeable. And being a noble gas, it's pretty small, not as small as Helium, but still it'll wander right through membranes that're gas-tight for diatomic molecules and larger compounds. However, that is almost always a rounding-error in terms of basement soil-gas infiltration. You can sometimes feel a literal breeze coming through a crack if the house is badly depressurized (windy day and stack-effect), you will never feel a breeze coming straight through a solid concrete or cinder-block wall. The spikes probably come from depressurization events like that. Sometimes the wind is angled in such a way that the house effectively forms a whistle or a manometer, and soil gas migrates at a greater rate during those times. This is somewhere that _passive_ sub-slab ventilation (drill a hole, connect a vent pipe to the outside, no fan) can often help significantly, along with caulking all the cracks. Seriously, don't bother with anything else until you've caulked.

2 ms·

> 1/2 of the basement is carpeted and drywalled Realistically, popping a hole in the slab and installing a fan might be less disruptive than tearing out all t

by myself248 4y ago

deskamess 4y ago
Can radon come in through the walls? We recently got a crack in the basement wall and a small water leak. Will be fixing the leak next spring, but I am curious if this is a cause for higher readings. The long term average is about 135 but it occasionally spikes to 200+. Also in Canada.
- myself248 4y ago
  Technically yes. It's a gas, so it'll permeate through anything that's gas-permeable. And being a noble gas, it's pretty small, not as small as Helium, but still it'll wander right through membranes that're gas-tight for diatomic molecules and larger compounds. However, that is almost always a rounding-error in terms of basement soil-gas infiltration. You can sometimes feel a literal breeze coming through a crack if the house is badly depressurized (windy day and stack-effect), you will never feel a breeze coming straight through a solid concrete or cinder-block wall. The spikes probably come from depressurization events like that. Sometimes the wind is angled in such a way that the house effectively forms a whistle or a manometer, and soil gas migrates at a greater rate during those times. This is somewhere that _passive_ sub-slab ventilation (drill a hole, connect a vent pipe to the outside, no fan) can often help significantly, along with caulking all the cracks. Seriously, don't bother with anything else until you've caulked.