# Tyvek application in crawlspace



## jaw22 (Dec 23, 2007)

Your main problem besides the insulation issues is that tyvek is only an air barrier NOT a moisture/vapor barrier in any way. It is likely not doing anything to cause or cure your problems. That moist summer air coming thru the vents is going to condense in the cooler crawlspace regardless if you seal off the room above. Alot of new work is going into sealing off the vents and making a closed crawlspace instead of the vents which like said allow a path for moisture laden air in the summer and super cold air in the winter. Also when the crawl is sealed up the walls of the crawlspace are whats insulated not the floor above and xps pink foamboard is used instead. 6mil poly goes on the floor and up the walls all seams overlapped by 12 inches or more and taped sealed.


----------



## marvmccull (Mar 27, 2008)

*craw space sweating*

call me stupid but i am still lost about how to fix the problem with sweating under the house. i live in kansas. the vents have all been closed for the winter. i looked under the house the other day and it looked like it was raining. winter is over now so i opened all the vents, hoping to fix the problem. what is causing this? thank you


----------



## jogr (Jul 24, 2007)

You aren't suppose to close the vents in the winter.

I agree with Jaw that the best way is to insulate the crawlspace walls and make it a conditioned area rather than ventilate it, particularly in some climates. In effect your crawlspace becomes a mini-basement.


----------

