venting basement/crawlspace

[raine]

I see that the new way to damp/proof ,vent radon in crawlspace is to lay a barrier over dirt floor and up the side walls to the joists. Add air tube ( looks like pvc) around perimeter with a small fan and vent out side of house. So ?, Why cant a person just use barrier covering the joists and add a bathroom fan in the crawlspace and vent to the outside ?

[shazapple]

Crawl spaces are difficult. Bringing them into the 'building envelope' to deal with radon/humidity/heat/etc is definitely more popular than ventilating them at the moment.

The issue with ventilating them is that during the summer you'd be pulling humid air into a cool space which would lead to condensation, rot, etc... In the winter if you have piping or ductwork you'd run the risk of freezing everything. By using a fan you also run the risk of pulling air from the inside of the house ($$).

[matchbookhouse]

I agree with Lee. Properly encapsulating and, if necessary, dehumidifying, a crawlspace is pretty mych the cutting-edge technique for dealing with moisture, odors, mold, creepy-crawlies, etc. I would think that radon mitigation would occur before the crawlspace was encapsulated - it should not need to be an ongoing process. Here in the damp mid-Atlantic, the last thing needed is to have extremely humid outside air let into the crawlspace through vents, and fans can't exhaust it sufficiently. Also, groundwater levels may be so high that additional mitigation may be necessary through interior french drains and sump pumps, and again, whole house dehumidifiers. I know the dehumidifier in my home's crawlspace runs pretty much 24/7/365 except when the temperature drops below freezing.

[Mick_VT]

I think the fan venting for Radon uses a fan which moves a LOT less air than a bathroom fan

[Don M]

I think the fan venting for Radon uses a fan which moves a LOT less air than a bathroom fan

Actually our radon fan is fairly powerful & sucks water below the cellar floor when the water table is high.

[phil]

I have a great blower for this if anyone needs one. It is in new condition, very quiet, and will make pressure or vacuum. its much different from the kind of blower on your furnace. More like a pump with an enclosed aluminum case and a tight tolerance rotor with vanes. I salvaged it from some demo machines that were used to expose film but in reading about it it seems it is the same kind of pump used for things like sewage fumes and such.

[Mick_VT]

I think the fan venting for Radon uses a fan which moves a LOT less air than a bathroom fan

Actually our radon fan is fairly powerful & sucks water below the cellar floor when the water table is high.

yikes - I had always thought they were weedy things lol