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Unbiased study of sealed crawl spaces ever done


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I'm new here. so maybe a dumb question.

in the debate over sealed vs non sealed crawl spaces has there ever been a study done by an independent organization- that is, some organization that is not selling services of "pushing technology".

I used to do a lot of confined space inspections on ships and the test equipment we used to test for hazardous gases and safe atmospheres had to be certified by an independent 3rd party government agency (NIOSH if I remember correctly). NIOSH only tested stuff they were not selling anything. you could not legally trust the manufactureres claims (or magazine ads).

Has any independent agency done such a study of pros vs cons on sealed crawl spaces. If non sealed works, even not well, I'd probably stay with it less there was good evidence that a new approach was really safe.

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University of Illinois, Champaign......William B. Rose.

Building Science Corporation probably has something specific on it; they've got stuff on everything else.

I wouldn't carry an worry about the information being correct; this isn't just crawlspace people selling stuff.

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A group out of North Carolina and I think a professor form Appalachian State University in Boone NC did an extensive case study on homes with sealed crawls. You should be able to Google it.

That's Advanced Energy. They probably know more about crawlspaces than anyone in this country.

Go here.

ONE TEAM - ONE FIGHT!!!

Mike

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It?s been my experience that almost every conventionally vented crawlspace I inspect here in Charleston has a moisture issues. The humidity plays a huge roll, ductwork doesn?t help nor does the floor insulation.

I encourage dehumidification and sealed crawlspace and try to educate my clients about them when I run into such. Even attics near the beach that are conventionally ventilated have moisture issues related to humidity.

I wanted to attach some pictures of actually homes I?ve inspected to show you how conventional type ventilated crawlspaces do not always work.

These first pictures are from a house in Mt. Pleasant only 6 years old. TJI floor joists. Floors were insulated, but animals had torn most of it down. No ductwork. I inspected in back in October and the moisture readings in the wood were about 10-12%. I would imaging during the summer months they would be 30% +.

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This one was a home in Johns Island that did not have ductwork or insulation. The first picture is before I started probing the wood and the second shows how rotted the wood is and my probe easily breaking the wood apart.

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Here?s one in West Ashley in the Byrnes Down subdivision. The picture speaks for itself.

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It?s been my experience that almost every conventionally vented crawlspace I inspect here in Charleston has a moisture issues. The humidity plays a huge roll, ductwork doesn?t help nor does the floor insulation.

I encourage dehumidification and sealed crawlspace and try to educate my clients about them when I run into such. Even attics near the beach that are conventionally ventilated have moisture issues related to humidity.

I wanted to attach some pictures of actually homes I?ve inspected to show you how conventional type ventilated crawlspaces do not always work.

These first pictures are from a house in Mt. Pleasant only 6 years old. TJI floor joists. Floors were insulated, but animals had torn most of it down. No ductwork. I inspected in back in October and the moisture readings in the wood were about 10-12%. I would imaging during the summer months they would be 30% +.

Click to Enlarge
tn_201222322428_IMGP4462.jpg

30.73?KB

Click to Enlarge
tn_2012223224323_IMGP4465.jpg

31.91?KB

This one was a home in Johns Island that did not have ductwork or insulation. The first picture is before I started probing the wood and the second shows how rotted the wood is and my probe easily breaking the wood apart.

Click to Enlarge
tn_2012223224729_IMGP1981.jpg

40.36?KB

Click to Enlarge
tn_201222322487_IMGP1982.jpg

43.52?KB

Here?s one in West Ashley in the Byrnes Down subdivision. The picture speaks for itself.

Click to Enlarge
tn_201222322491_P8200323.jpg

82.52?KB

What I've never understood is why, since they've known for a lot of years that humidity in crawls causes major issues in South Carolina's really humid climate, is why they don't routinely treat the underside of houses there with a fungicide before they finish them off. Hell, if the builder would have only gone under that house and saturated the hell out of everything with BoraCare before having the insulation installed, the underside of that house might have gotten damp but it would have stayed free of wood fungi.

$500 - the cost of a couple of gallons of BoraCare and the labor involved with having a Snuffy go under there with a pump sprayer and nuke everything.

$500 per hour - the cost of a lawyer for one of the hundreds of hours he'll be dinking around 'defending" the builder when a homeowner sues over rot like that.

ONE TEAM - ONE FIGHT!!!

Mike

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would use of pressure treated wood for all crawl space facing wood (subfloor etc) solve the problem or would the mold just be on top of the pt wood?

It would prevent decay of the wood. It wouldn't solve the moisture problem. If debris accumulates on the PT wood, mold will grow on the debris.

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Borecare is rarely used around here. Mainly just for a secondary prevention measure for termites. While it would help prevent growth it?s still not preventing the moisture issues due to high humidity in a confined space.

The only thing I?ve seen that actually works is sealing off the crawlspace vents. Add a vapor/moisture barrier (depending on the amount of ground moisture) and installing a dehumidifier. The dehumidifier will maintain a humidity level that will not let the fungi grow. I?ve seen it work time after time.

Here a picture of one that a buddy of mine installs.

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My experience is that if you have a good vapor barrier on the floor I would argue to insulate the perimeter and condition the crawlspace.

Absolutely. Preferably, closed cell foam sprayed from rim lapping down over the VB.

I was even in one the other day that had the floor sprayed for the VB. It was like crawling around in a Willy Wonka cave.

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While many, many vented crawl spaces don't have a 'problem', there are plenty out there that can have amazing issues. when you stop and think about it, crawl spaces are bathed in humidity year round, and the thinking is the humid air outside is better than what's beneath the home.

The idea that every crawl space be treated with an antimicrobial is good, but limited. Crawlspaces that perhaps 'circulate' poorly attract bugs. The insulation can get saturated. Wood moisture levels over about 16% will grow fungi regardless of whether there's a treatment on it or not, and I see houses every week that have moisture levels high enough to rot wood. An antimicrobial won't fix that.

To answer the OP, Advanced Energy did a couple of studies - one focused on the hot, humid south and a 2nd in multiple locations across the country, on sealed crawl spaces and their benefits. CrawlSpaces.org

However, you may consider this 'unbiased' and pushing a technology. I don't, but YMMV.

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