Excess condensation in crawl what to do?
measureright
| Posted in General Discussion on
I have quite abit of condensation in a crawl space , coming off HVAC duct work etc.
The crawl space is on a brick veener foundation that is 8ft tall on the rear side,with automatic foundation vents put in to code per NC code book. We have had in excess of 90 degree wather & 90 degree humidityfor 30 days. Should i close 75% of the auto vents by taping them shut for summer?
Replies
Read up on crawlspaces at http://www.buildingscience.com/
Sounds like you need to do a conditioned crawl: insulate the walls, vapor barrier on the floor, if dirt, no vents, and shoot conditioned air into the crawl.
But I'm not in your area so I'm not sure.
If you think about it, do you really want to allow hot humid air into a cooler crawl space with even cooler duct work running through it?
Treat it like a basement, IMO
Amen to what he said.
what is the r valve of the duct insulation?
r4? R6 is better.
You have me in the blind about 2/3 of the details invo;ved in this scenario.
A problem like this involves insulation, vapour barriers, use of crawl space, materials involved, and climate. All I really know now is climate and vents?
does condensation appear on any other surfaces than just the ducting?
Does drippage from ducting drop onto anything other than a dirt surface?
is there a VB on that surface or iof there is a mud slab/rat slab, is there a VB under it?
Is there mildew or other signs of mold on joists or other exposed wood?
Is the underside of the floor insulated? If so, does the insulation have a VB surface and which way does it face?
There could be a range of options from expensive to costless, depending...
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To clarify a few points. The condensation is only on the HVAC 12 SER Payne unit as well as the duct work which is silver flex .
The excess condensation drips onto a 6ml plastic vb, Iam not talking about more than several small puddles on the vb of less than 50ml total.
It is a walk in Crawl space with a door at one end due to the height of the foundation of about 10ft at one end.
There is no visible mold at this time on anything I could see .
The insulation is r19 unfaced fiberglass batts .
Thanks for your interest I hope this answered your questions
Givern that, I would simply close off the vents during this warm humid season as you thought right.The reasoning is this - There were two most likely sources for the moisture that you see condensing. One is from the ground and the other from the air. Since you have a plastic VB on the ground, it is unlikely that you are gaining much moisture from there. That means that the greatest problem is the warm air carrying moistue in with it, to come in contact with the cool surfaces. By denying this air entry, you drastricaly reduce the amount condensing and puddling.For added insurance, seal the plastic VB ground cover at edges and be sure it has no rips and tears.Open the vents again in more moderate weather and let them close in freezing weather.One more question. Does the air unit have a drain line for condensate supplied to it? That should be a part of the installation, but I can imagine that it might be neglected by a mechanic who assumed that nobody would ever notice a small puddle on the ground, without considering that the builder would have provided a VB.
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