I've been doing a lot of research on crawlspaces. Hey... I started this entire process wanting to put down a wood floor and now I'm working on the crawlspace. My wife thinks I'm nuts.

Anyway... I have a moderately modern crawlspace. The 6 mil polyethylene vapor barrier on the dirt needs some small repairs but overall it is good. I'll repair and secure the exhisting stuff and probably run some up the walls and tape all seams to improve what I have.

We need to do some exterior work to better slope the west side of the house (we are on a mountain) where the rain can be an issue during the rainy season. Most of the year it is fine but I'm going to rent a backhoe and grade it better this summer and upgrade drainage with a better improved french drain away from the house. I'm removing all vegitation away from the perimeter of the house.

I'm also blocking a couple of the crawlspace vents that are under an attached porch. I'm also going to use forced air to circulate outside air through the crawlspace when the outside humity level is lower than that of the crawlspace. The cost of adding these is about $500 in fans, sensors and control unit.

Our insulation has fallen out from between the joist in several areas. I was intially going to just buy some more wire supports and replace some of the more ragged sections. After doing research though I'm seriously considering one of these foil/bubble wrap installations.

http://www.insulation4less.com/installa ... _space.pdf

This seems to have a couple advantages.

#1. It controls moisture ingress into the entire subfloor effectively isolating the joist & plywood subfloor from crawlspace humity/moisture. This should translate to lower mold/mildew and long-term rot since 99% of the wood is on the dry side of the moisture barrier.

#2. The insulation value is not effected by moisture content like fiberglass batt insulation. I've learned that with high moisture content (like in my crawlspace) that the effective R value of our insulation is probably close to R10 rather than the R21 it is rated at.

#3. It is effective at preventing convective heat loss from holes in the subfloor plumbing, electrical, fixtures, drains etc...

#4. It should be easy to retrofit install and the material cost is only $500 for my entire crawlspace. No special tools or contractors needed.


Has anybody done this type of installation? Input?