In the process of encapsulating my crawl space. Currently I have insulation between the above floor joist.

My question is, when I finally have the vapor barrier sealed and the rigid foam put on the walls and vents sealed, should I remove the insulation in the floor joist or is it ok to leave it? As always, thanks.

 

Hi lgb,
It somewhat depends upon the air and resulting temperature in that crawl. removing the floor insulation will increase the air flow up into the house and reduce the temperature difference between the house and crawl. If you are opening a supply and return to that space and it is warmer than the floors above, removing the insulation will help to warm the floors above.

May be best to wait and see and remove only areas that are needed if any.

Bud

 

HI,
can I just ask Lgb0250 why you're putting up rigid foam on the walls? I presume that you have a cement foundation- is it weeping moisture or was this advised to "seal" the space somehow? (won't mold grow behind it?) I ask because I have temperature issues in my crawlspace and nobody around here in NewEngland ever mentions the "walls". I have the overhead insulation as well but my floor in the house are still cold. It's a mess. Just curious if adding what you're doing would help or hurt my situation. (do you have ANY moisture issues?) Is it "cold" when you go down there?
(I hear that's a sign of moisture- the feeling of cold temp change)

 

First of all, thanks Bud. I think I'll follow your advice.

Hi spike. In my case living here in NC, I was experiencing very high humidity during the summer months which caused condensation to build on my air handler which is in the crawl space. My hardwood floors have actually shown signs of warping because of this. My crawl space was nothing but dirt with what looked like some tarp thrown over it! It is also currently vented with bare foundation walls.

I've done a lot of research and so far I've put down a 10 mil vapor barrier. Still in the process of attaching it to the walls and then I have to tape all of the seams. I'm still debating whether to put the 2" rigid foam on the walls or to put some insulation batts up instead. I've read that the batts may do the job and would seem to be the easier installation with just having nail up the firring strips. Without a truck it's going to be real hard to do the rigid foam 4x8 sheets! Then I still have to seal all the vents and put a supply/return in to totally condition the space.

This is a long process for someone my age with health issues to boot but I need to get it done before the humidity comes back with a vengeance come April. I want to make it clear, I don't have any direct moisture problems in the crawl space, basically just high humidity in the summer. I wish I could offer you some decent advice spike, but I'm really not familiar with New England home. What I do know is that if you ask, there are some really great experts here that will offer their advice. Good luck.

 

Hi Spike,
Start another thread and I'll pick it up and comment over there.

Bud

 

lgb, I see I didn't give you my favorite link on crawl space encapsulation. Photo #5 is what you want it to look like when done. At the bottom you will find related links which will have more related links and in all more information than you ever wanted to read .
BSI-009: New Light In Crawlspaces — Building Science Information

Bud