I want to test mainly for Radon gas and Methane. Reason being we have a new house built on crawl space, crawl space is one of the sealed type that is fed heated/cooled air off the main supply plenum of the furnace/ac unit. There are no return air vents in the crawl space so no air is intentionally drawn into the htg/ac ducts, but since the crawl space is not vented to outside I need to check for Radon and Methane that might waft up from the ground and hang in the sealed crawl space, which could eventually get into the living space above. The crawl space is covered with chat gravel and then has 8 mil plastic vapor barrier, but the vapor barrier has a lot of seams. I'm going to seal all the seams with duct mastic, but I still wabnt to test the air.

What else besides Radon and Methane should I test for? I have no reason to suspect either gas is present in dangerous quantities, I just want to test for peace of mind.

 

Methane isn't as prevalent as radon. While large quantities of methane can kill ya fast, radon kills over time. I wouldn't worry about anything else unless there are ecological threats in your area such as high levels of halogens or a large hazardous waste site.

 

I was thinking about getting one of these:

http://radonmonitor.com/

 

Do you have gas or electric heat? If it's gas, you need to make sure it's vented outside somewhere. It probably goes through your roof.

Why didn't they install vents in the crawl space? I would think the building code would require them.

 

On the newer houses they're conditioning the air in the crawl space by the furnace and a/c unit supplying air to the crawl space. Its in compliance with code. But all they do for a vapor barrier is lay down sheets of visquine plastic, 8 mil thickness. They don't seal the seams. So any soil gases could theoretically accumulate in the crawl space air, since they could get past the vapor barrier via gaps and seams.

I've been researching this, and it looks like the only way to guarantee no soil gases enter the crawl space is to encapsulate the crawl space. One example of encapsulation is this:

http://www.basementsystems.com/crawlspace/

But, I want to test for the main soil gas to be concerned about, Radon, before I look at encapsulating the crawl space.

 

Just a thought.......

If you seal the plastic real well, will the gases inflate like a ballon and cause your house to float in space .





Sorry, I know this is a serious concern to you.....but I had this illusion and thought it was funny......I'm strange.

 

LOL, no worries. The reason I'm not going to test for methane is because after a few beers I would skew the test results.