Why are you closing it off?

 

Well pec perhaps med is planning on sealing his basement and insulating the walls and covering the floor with plastic as required by the energy code to make the crawlspace inside the building envelop thus saving energy loss cooling or heat from his ductwork and furnace or air handler.

Just like you would in your attic which is what lots of folks are doing in Florida now. Thank you very much

 

I would use foil faced 2" polyisocyanurate. And sure; just paint the outside black if it bothers you.

You could use styrofoam but it's flimsy and the only easy way to cut it so it comes out nice is to use a table saw.

PHM
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i

 

How can I cut 2" polyisocyanurate? Do I put the foil side towards the outside or the crawl space?

Thanks!

 

You can cut the polyiso with a straight edge and a sharp knife and make a real nice job of it. Even if you just cut through 50-60% and then bend/brake the foam it breaks clean.

If you are just blocking the vents I would put the foil out to face any weather.

If you are also doing the walls I would put the foil face in - and at least make it a cakewalk to use 3" aluminum foil tape to make the joints nice. <g>

PHM
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I hope you are planning to use a quality dehumidifier and totally seal the earth with heavy plastic sealed well at the seams.

 

As thick as possible. Make sure you cover the ground fully with the seams overlapped (6-12”) and taped. Run up the wall at least 12” and secure it to the foundation wall. Masonry is pourous so it’s best to insulate the foundation wall as well (with foam board or spray foam) then cover with the same vapor barrier as the crawl, lapped and taped. Then you’ll need conditioning of some sort.

Here’s one I did

 

J, that would be a heavenly crawl space time work in. I don't see any like that.

 

Crawlspace depot has supplies and instructional videos...

 

A thing of beauty.
Icing on the cake, a Santa Fe Compact to maintain <60%RH during wet evenings and rainy weeks.
Teddy Bear

 

If I use the Polyisocyanurate board, how can I paint it? Which paint works best?

The problem is my vents don't close all the way so I'll be able to see the Polyisocyanurate slightly through the vents when outside. Since the vents don't close completely the Polyisocyanurate will get damp from time to time. That being said, should I still use Polyisocyanurate?

Thanks guys!