How much moisture comes from crawlspace soil?

[Joe Funderburk, CMI]

Originally Posted by jbraun

All crawlspaces need to have moisture barriers, right? Regular venting will not eliminate enough moisture, in most circuimstance, in crawlspaces without moisture barriers.

I disagree. I've seen many crawlspaces without vapor barriers and no problems. If the house sits on top of a hill, has good functional gutters, good ventilation, has a relatively high crawl space, etc. there may be no moisture problems at all without a vapor barrier. I do not recommend a vapor barrier unless I see an issue. (I do, however, report the presence and amount of a vapor barrier for information purposes.) Who am I to advise someone to spend hundreds of dollars to correct a non-existent problem?

[James E. Braun, CMI]

Originally Posted by jfunderburk

I disagree. I've seen many crawlspaces without vapor barriers and no problems. If the house sits on top of a hill, has good functional gutters, good ventilation, has a relatively high crawl space, etc. there may be no moisture problems at all without a vapor barrier. I do not recommend a vapor barrier unless I see an issue. (I do, however, report the presence and amount of a vapor barrier for information purposes.) Who am I to advise someone to spend hundreds of dollars to correct a non-existent problem?

Please notice I did say "in most circumstances"

[Joe Funderburk, CMI]

Originally Posted by jbraun

Please notice I did say "in most circumstances"

Now I see that.

[David A. Andersen]

Joe, did you take psychrometric readings of the air to determine this?

As I posted above, the soil may look very dry (thats because all the water is now in the air).

[QUOTE]I find many CS's that have 100% rh and the soil is dry! [/QUOTE]

I do not recommend a vapor barrier unless I see an issue. (I do, however, report the presence and amount of a vapor barrier for information purposes.) Who am I to advise someone to spend hundreds of dollars to correct a non-existent problem?

You seem to worry about a lot of other stuff that is not necessary, why stop here? A vapor barrier is an industry standard for several reasons.

Just interesting that you take a stand at this point.

[Joe Funderburk, CMI]

Originally Posted by dandersen

Joe, did you take psychrometric readings of the air to determine this?

As I posted above, the soil may look very dry (thats because all the water is now in the air).

...A vapor barrier is an industry standard for several reasons

I take moisture readings of the wood floor structure in various places. I look for wet soil or signs of moisture intrusion. I look for signs of fungi. I look for decay. I look for deteriorated insulation. I look for proper ventilation. If I don't see a concern, why recommend a fix when there isn't a problem?

My own house has been sitting on top of a hill with dry sandy soil since 1880. There is not a vapor barrier and the framing is in exceptional condition. I'd be pretty PO'd if a future home inspector recommended a vapor barrier just because it is "industry standard".

What I'm talking about, mainly, is putting such an issue in the Summary section of a report. The Summary highlights "significant" issues, get's all the attention, and is required in NC. I wouldn't be opposed to putting a note recommending it in the body of the report, as long as it wasn't blown into a "significant issue" when no detrimental affects were observed.

[David A. Andersen]

I take moisture readings of the wood floor structure in various places.

So you are testing. Moisture of the wood is relative to moisture in the air.