How to vent radon gas?

[Bug]

So my fiance and I bought a house built in 76 that has no vents for the crawl space. Looking around the perimeter, there is only one place to vent without cutting through the foundation.

 

So how am I supposed to cut a vent hole through the foundation?

I could drill some holes easily enough but how do I connect the dots?

[denalidave]

Have you already tested for radon to see if it is even necessary to vent the home?

[bobinc]

Yeah-- get it tested first. High radon homes are relatively rare around Puget Sound. Not saying you don't have a problem but based on the field studies I've been involved with, it is pretty rare on the west side. if you do have a problem, there are several options.

[Fairweather]

Radon aside, you should still vent your foundation to allow the passage of sewer gas should any of your drain pipes ever rust through. Also, I'm not sure you can ever resell the home without proper venting of the crawlspace. (?)

[Bug]

It has not been tested but we did have a building inspector look at the house before we bought. He listed it as a fix we should do. It is code now in King county. But since the house was built in 76 it is grandfathered as is.

 

But thanks guys. I will look into having it tested. We plan on spending quite a few years there.

And Fairweather is right too That was another thing the inspector listed plus just mildew releif in case there is any dripping or condensation.

[Recycled]

Yes, you'll want vents every 10-12 feet around the foundation + black plastic vapor barrier on the dirt. The main concern around here isn't radon or sewer gas, but high moisture levels which promote fungal or insect damage.

 

I've always drilled 8-10 perimeter holes and then chiseled out the center. If you rent a fairly beefy rotohammer, you should be able to knock out a vent hole in 30 minutes or so. Have a sawzall or grinder on hand to deal with any rebar you run into while chiseling.

[billcoe]

Good points and advice above. Who builds a crawl space with no venting? That's insane as wet as it is around here.

 

One more thing, you might try checking with a concrete coring or concrete cutting company to see if they can saw the vent holds, they'd most likely cost more (although you never know, depends how long it would take you to do it with the rental fee adding up) but if they can do it, it would be much cleaner I'd expect.

[Frikadeller]

Good points and advice above. Who builds a crawl space with no venting? That's insane as wet as it is around here.

 

 

Well, He should first check to make sure that the crawl space is not being used as a return air plenum for the Furnace/Air conditioning system. It's rare, but I have a few clients out here in PDX that have systems like that. (I am a HVAC Contractor) I have tried to sell them a proper duct system, but they are cheap bastards!

 

Those houses do not have any foundation vents, because that would screw with the air to the furnace, and make it very in effecient . Believe it or not, but it was not against code to do that back in the 70's..

 

 

[Bug]

Hmmm. Interesting. I will have to crawl back in for more recon....

Thanks guys.

[Frikadeller]

Hmmm. Interesting. I will have to crawl back in for more recon....

Thanks guys.

 

If you suspect that the crawl space is in deed the return air plenum for the furnace, it should be pretty easy to spot. (well for me it is...)

 

Just look to see if the knee walls, if you have them are insulated, and that the vapor barrier (the plastic sheeting on the floor) goes all the way up to the "ceiling" of the crawl space. Also, crawl over to where the furnace penetrates the floor space, you should see a cut out in the "ceiling", and if you look up there, you will see the bottom of the furnace. Also, you can tell if you have a grate in your floor of your house (A pretty big one), and you shine a flashlight down it, you should see the crawl space. If so, you have a crawl space return plenum.

 

I am suprised that your home inspector missed that part. Well, actually I am not, many of those guys are hacks.

[G-spotter]

Just relax your sphincter and it should vent no problem

[Bug]

I vent in your general direction.

Edited August 24, 2008 by Bug

[Dechristo]

The "one cheek sneak" works for me.

[MarkMcJizzy]

1) The point about the crawl space being used as a return plenum is a valid one, although very improbable. You shpould be able to identify and locate your return ducts.

 

2) Radon is normally associated where the basement rocks are (broadly) acidic granites in character. The Puget lowlands are extensively worked glacio fluvial sediments, and clay. These generally have not been associated with a lot of radon.

[Mal_Con]

A few places around Issaquah, Renton and Newcastle may have some Radon associated with coal mines but most of these are sealled off by clay and ground water layers.

[canyondweller]

Concrete cutter will be a $400 minimum.

[Phil K]

A few places around Issaquah, Renton and Newcastle may have some Radon associated with coal mines but most of these are sealled off by clay and ground water layers.

 

Partially true: it isn't the coal, but that sweet Renton granite is a well known radon source.

 

 

 

[111]

A Bosch Bulldog and about 10 bits

[sobo]

A few places around Issaquah, Renton and Newcastle may have some Radon associated with coal mines but most of these are sealled off by clay and ground water layers.

 

Partially true: it isn't the coal, but that sweet Renton granite is a well known radon source.

Well, somebody had to say it eventually...