Please register to participate in our discussions with 2 million other members - it's free and quick! Some forums can only be seen by registered members. After you create your account, you'll be able to customize options and access all our 15,000 new posts/day with fewer ads.
WOW, what a confusing subject/question! Based on what I can ascertain from I-search, it seems like there is a split decision on whether or not to have a vapor barrier on a bare dirt floor crawl space.
Our modular home (built in 2000) is on a permanent concrete foundation that has about 4-1/2 ft. high crawl space. There are two sets of screened air vents on each wall and they have the flapper doors to close off air flow for winter. During the summer since we've been here, we leave them open. The floor is dirt and has no plastic vapor barrier. The soil is dry/slightly moist and no standing water. The home inspector made no mention of a vapor barrier not being there and there were no observed issues with moisture, mildew, mold, etc.
The Stratford home construction uses fiberglass insulation between the floor joists and a fairly thick plastic vapor barrier across the bottom. I'm not sure whether the on-site builders for this area (southwest Montana) normally install vapor barriers on the dirt floors or not. I plan on calling Stratford to see what they say.
Leaving the vents open in winter is not an option as the ice cold air blows in like a freezer. With them closed, I'm a bit more concerned about not having a vapor barrier on the floor. Anyone have a similar set-up in this region and how is your house set-up?
WOW, what a confusing subject/question! Based on what I can ascertain from I-search, it seems like there is a split decision on whether or not to have a vapor barrier on a bare dirt floor crawl space.
Our modular home (built in 2000) is on a permanent concrete foundation that has about 4-1/2 ft. high crawl space. There are two sets of screened air vents on each wall and they have the flapper doors to close off air flow for winter. During the summer since we've been here, we leave them open. The floor is dirt and has no plastic vapor barrier. The soil is dry/slightly moist and no standing water. The home inspector made no mention of a vapor barrier not being there and there were no observed issues with moisture, mildew, mold, etc.
The Stratford home construction uses fiberglass insulation between the floor joists and a fairly thick plastic vapor barrier across the bottom. I'm not sure whether the on-site builders for this area (southwest Montana) normally install vapor barriers on the dirt floors or not. I plan on calling Stratford to see what they say.
Leaving the vents open in winter is not an option as the ice cold air blows in like a freezer. With them closed, I'm a bit more concerned about not having a vapor barrier on the floor. Anyone have a similar set-up in this region and how is your house set-up?
Do you have a picture of that? It doesn't look like it's the way it is done here in the North East. I have insulation between the joist of the crawlspace but definitely not covered with plastic. That would be a bad idea. Keeping free flowing air down there is important. Don't close out those vents. It is cold but no different than your attic space.
Even though this is a GA gov site, the relevant information is the same for any state that follows the IRC codes.
After you fully understand these sections, tell us if you think your builder built your home correctly. From there we can join the arguement of what's better- vented or non-vented.
Building Science website or Green Building Advisor, both say a vapor barrier is needed in crawlspaces. Most say to turn it into conditioned space, meaning heated. There are lots of options, all based on budget really. Good Luck.
There is no debate at all about whether you should have a vapor barrier. In fact, you need 10 times more ventilation for foundations without a barrier than with one.
There is some debate about whether to have your vents open or shut and when and that will depend on your climate.
Please register to post and access all features of our very popular forum. It is free and quick. Over $68,000 in prizes has already been given out to active posters on our forum. Additional giveaways are planned.
Detailed information about all U.S. cities, counties, and zip codes on our site: City-data.com.
Please register to participate in our discussions with 2 million other members - it's free and quick! Some forums can only be seen by registered members. After you create your account, you'll be able to customize options and access all our 15,000 new posts/day with fewer ads.
