Help with crawl space remediation
#1
08-27-13, 04:55 PM
Help with crawl space remediation
We moved into a house a couple of months ago with a finished basement. A section of the basement has a crawlspace which is directly below the family room. After some rain, the crawlspace had puddles of water on the vapor barrier which was not sealed. After fixing the clogged downspout in the front of the house, the problem was fixed.
The crawlspace is about 400 sqft and has areas of dirt which was eroded and other areas which have hard rocks. The insulation on the ceiling of the crawlspace was mice infested which I removed and threw away. It also has duct work running through the crawlspace. The previous owners also had a radon system installed that goes through the crawlspace but was told that it was done incorrectly.
I had a couple of companies come out and give me an estimate to put down a new vapor barrier and seal it to the wall. They told me the radon system needed to modified since there was no perforated pipe laying on the floor of the crawlspace.
My questions are as follows:
1)Should I put something in the crawlspace to even the ground? If so what should I use? (Gravel or some kind of dirt)? The companies said I should not worry about.
2)Should I put some kind of water alarm sensors under the vapor barrier or is this overkill? How would you know if you have an external water problem if water would be coming under the vapor barrier and you could not see it?
3)Should I insulate the walls and make a small vent and return in the duct work so the space would be conditioned after putting down sealed vapor barrier?
Thanks
-Dimitry
The crawlspace is about 400 sqft and has areas of dirt which was eroded and other areas which have hard rocks. The insulation on the ceiling of the crawlspace was mice infested which I removed and threw away. It also has duct work running through the crawlspace. The previous owners also had a radon system installed that goes through the crawlspace but was told that it was done incorrectly.
I had a couple of companies come out and give me an estimate to put down a new vapor barrier and seal it to the wall. They told me the radon system needed to modified since there was no perforated pipe laying on the floor of the crawlspace.
My questions are as follows:
1)Should I put something in the crawlspace to even the ground? If so what should I use? (Gravel or some kind of dirt)? The companies said I should not worry about.
2)Should I put some kind of water alarm sensors under the vapor barrier or is this overkill? How would you know if you have an external water problem if water would be coming under the vapor barrier and you could not see it?
3)Should I insulate the walls and make a small vent and return in the duct work so the space would be conditioned after putting down sealed vapor barrier?
Thanks
-Dimitry
#2
08-28-13, 08:53 AM
There's no need to level the crawl space. If you've corrected the water infiltration problem there's no need for moisture sensors. A clear plastic barrier would let you keep an eye on things.
Decide whether you want to seal and condition the space or ventilate and insulate against it. Keep in mind whether the radon is present in the finished basement or only in the crawlspace as you decide this.
Decide whether you want to seal and condition the space or ventilate and insulate against it. Keep in mind whether the radon is present in the finished basement or only in the crawlspace as you decide this.
#3
08-28-13, 09:10 AM
Group Moderator
Sounds like sealing the crawlspace from the outside and having it open to the HVAC system and the rest of the house is the way to go since you have ducts running through there.
Insulation in the ceiling of the crawlspace would not be needed this way, you would want it on the outside walls of the crawlspace.
Insulation in the ceiling of the crawlspace would not be needed this way, you would want it on the outside walls of the crawlspace.
#4
08-28-13, 05:28 PM
Nashkat1,
A couple of questions:
1)You say to use A clear plastic barrier which would let you keep an eye on things. Every where I read, it says the best is to use 20 mil vapor barrier. What is your recommendation because I thought they do not make any of them clear plastic?
2)You also said Keep in mind whether the radon is present in the finished basement or only in the crawlspace as you decide this. When they did the radon test before we bought the house, it showed a 6 pCi/L but how can you tell if it is coming from the crawlspace or finished basement. Part of the home settlement was for the previous owners to install a radon system and after doing the test, the result was 1.2 pCi/L.
Thanks
-Dimitry
A couple of questions:
1)You say to use A clear plastic barrier which would let you keep an eye on things. Every where I read, it says the best is to use 20 mil vapor barrier. What is your recommendation because I thought they do not make any of them clear plastic?
2)You also said Keep in mind whether the radon is present in the finished basement or only in the crawlspace as you decide this. When they did the radon test before we bought the house, it showed a 6 pCi/L but how can you tell if it is coming from the crawlspace or finished basement. Part of the home settlement was for the previous owners to install a radon system and after doing the test, the result was 1.2 pCi/L.
Thanks
-Dimitry
#5
08-29-13, 08:42 PM
Member
Join Date: Mar 2013
Location: USA
Posts: 412
Upvotes: 0
Received 0 Upvotes
on
0 Posts
I'd suggest slopping it; (as radon is about 9 times heavier than air) any low spots in the soil surface level will pool it there. If you have 6" of gravel over the ground area, covered with a 10m plastic (clear--- only if needed to see plumbing lines for future inspections, or use black); you won't need the perforated pipe. If just dirt and no pipe; slope the grade to the exhaust vent pipe; http://www.buildingscience.com/docum...ance-and-codes
Location merits attention when HVAC is down there: cold climate= insulate floor; hot climate= insulate walls;http://www.advancedenergy.org/buildi...l%20Spaces.pdf
Plastic 1 foot up walls; taped or positive attachment, tape all seams after overlapping, if f.b. walls- leave top 2" open for termite inspection; Termite Basics: Activity By Region
That small of a crawl- another option (used for wet crawls, cover foam board against ignition); for other readers, fig.7; BSI-009: New Light In Crawlspaces — Building Science Information
Gary
Location merits attention when HVAC is down there: cold climate= insulate floor; hot climate= insulate walls;http://www.advancedenergy.org/buildi...l%20Spaces.pdf
Plastic 1 foot up walls; taped or positive attachment, tape all seams after overlapping, if f.b. walls- leave top 2" open for termite inspection; Termite Basics: Activity By Region
That small of a crawl- another option (used for wet crawls, cover foam board against ignition); for other readers, fig.7; BSI-009: New Light In Crawlspaces — Building Science Information
Gary
#6
09-05-13, 06:01 PM
Gary,
I had a company come and give me an estimate on laying down a vapor barrier. They said they do not have a 10 mil clear vapor barrier, only a 6 mil. Do you think that is too fragile and would tear easily?
Thanks
-Dimitry
I had a company come and give me an estimate on laying down a vapor barrier. They said they do not have a 10 mil clear vapor barrier, only a 6 mil. Do you think that is too fragile and would tear easily?
Thanks
-Dimitry
#7
09-06-13, 06:38 PM
Member
Join Date: Mar 2013
Location: USA
Posts: 412
Upvotes: 0
Received 0 Upvotes
on
0 Posts
10-12m if there is much traffic for inspections, HVAC, etc. Otherwise, 6m is fine, IMO. Leave room for the plastic to move a little while crawling, rather than pulled tight and rips easier when under tension. Some pin it down with insulation wire supports bent in a "U" shape or sand bags. No need for clear plastic, black is the norm.
Gary
Gary
#8
09-07-13, 05:09 PM
Gary,
If you use black vapor barrier instead of clear, how can you tell if there is a leak from the outside such as gutters got clogged or crack in the foundation. Originally, I was going to use water sensors but then thought clear vapor barrier is cheaper.
Thanks
-Dimitry
If you use black vapor barrier instead of clear, how can you tell if there is a leak from the outside such as gutters got clogged or crack in the foundation. Originally, I was going to use water sensors but then thought clear vapor barrier is cheaper.
Thanks
-Dimitry
#9
09-07-13, 07:49 PM
Member
Join Date: Mar 2013
Location: USA
Posts: 412
Upvotes: 0
Received 0 Upvotes
on
0 Posts
It is your crawl. I'd do annual inspections if gutters clog. The leaders should be run out 6' away from foundation. Ground sloped away, up-grade the downspouts to next larger size if clogging and get a leaf guard system. If worried about cracks in crawl foundation, excavate and waterproof on the exterior, though you might research it more to warrant your concerns. It would need to a tall wall before I'd do much.... even then...
Did you canned foam/caulk all plumbing/wiring holes in the floor, air-seal the rim joist with foam board? http://www.wag-aic.org/1999/WAG_99_baker.pdf
http://www.buildingscience.com/docum...l_seal_rev.pdf
Info-512: Crawlspace Insulation — Building Science Information
Gary
Did you canned foam/caulk all plumbing/wiring holes in the floor, air-seal the rim joist with foam board? http://www.wag-aic.org/1999/WAG_99_baker.pdf
http://www.buildingscience.com/docum...l_seal_rev.pdf
Info-512: Crawlspace Insulation — Building Science Information
Gary
