Replies

1. 
   Clewless1 | Jan 27, 2009 03:58pm | #1

   No comment on the foam ... other than expensive. I'd personally avoid it for that reason and consider ways to control the mice. How about Tyvek for the under floor to hold the insulation in place? Conceptually, I think that works ... but I've not heard of people doing it. Tyvek is quite strong.

1. 
   jackboy | Jan 27, 2009 05:12pm | #3

   Thanks for the reply. I've talked to Pest Control folks about the mice. Don't have a 100% fix yet. I like the Tyvek idea, although that might happen anyhow if we install for Radon Mitigation, which is a big issue here. I know spray foam is pricey, but it's a great product and seals everything up and stays in place.

1. 
   Clewless1 | Jan 28, 2009 03:48am | #9

   Just remembered. You might check w/ the BO, too about the foam. Exposed foam is usually a no no code wise (it's a fire hazard ... I recall foam must be protected by having drywall in "substantial contact" with the foam insulation. I think it applies to crawlspaces as well.

1. 
   jackboy | Jan 28, 2009 04:11am | #10

   Would that hold true for spray foam as well as rigid?  Guess I'll check with my Inspector.  He'll be on another job of mine next week.  Windsurfer dude are ya?

1. 
   Clewless1 | Jan 28, 2009 06:02am | #11

   Most foams are a cousin of polystyrene or urethane/polyiso, so it has to be protected. But the inspector should be a good resource. Let us know what he says, OK?

   Been sailing about 25 years now. Sailed the Gorge a lot (I own two houses up there). Sail a lot down here in SoCal, too (am I lucky or what?). I really love it. I gotta get in shape and lose a few pounds here this spring before I go out again.

    

2. 
   jackboy | Jan 28, 2009 07:57am | #12

   We sailed heavy for probably 8 years.  Colorado not the best place for windsurfing.  My real sport was hang gliding for 25 years.  Now fly sailplanes.  I like landing on wheels!  I'll let you know what the inspector says. - Yes.  You are lucky to sail the gorge and SoCal.  Keep it up!

2. 
   Dreamcatcher | Jan 27, 2009 04:13pm | #2

   did you say 4 foot...why not just insulate the walls and floor with 4'x8' sheets of foam? I recently did it to my own house and the results are amazing. I took the fiberglass off the heat ducts and now I get a "radiant heat" floor.

   Although I am not positive, I don't think mice like any type of foam. I do know that crawlspaces are often moist and moisture loves fiberglass and cellulose.

   DC

1. 
   jackboy | Jan 27, 2009 05:19pm | #4

   DC - 4x8 sheets of foam would give good R-value, pricey stuff, and maybe difficult to install. My thought on the spray foam was it would fill the space between the floor joists and rim joist just fine which is where most of the cold air would come from. It would also stick to the concrete walls good too. I need to keep the dirt floor uncovered in case we do Radon mitigation at a later time. Thanks for your ideas.I think I'll price out the 4x8 sheets just in case.

1. 
   Dreamcatcher | Jan 27, 2009 08:25pm | #5

   I know what you're saying, I priced out spray foam and about shrieked at the cost. I also priced out a company for a "crawlspace package" which included foam on walls and fully seamed vapor barrier, my jaw dropped at the $8000 price tag for 1300sf.I ended up finding a great deal on 2" rigid insulation for less than $10 a sheet...lightly used. I bought it from a retail store demolition company. The guy said they commonly gut out stores in malls and the rigid is just lightly glued to the block walls and such. I just had to pop off the glue daubs with a putty knife (was quick and easy) then I sliced up all the pieces to fit the joist bays on the table saw. Cut them tight and beat them into place with a rubber mallet. If they are a bit too tight, use the concrete to rasp a little off. I used a boning knife to make custom lengths when necessary and a sawzall blade to cut around any pipes. In the joist bays where I have ducts and registers, I doubled the insulation. I was going to go back and spray foam around the edges but they ended up going in so nice and tight that it wasn't even needed. For the pieces on the walls, I used construction adhesive and a few of powder actuated nails per sheet just to hold them till the glue set up. In all, it took me about 3 short days to cut up and install 40 sheets. The result is a dream crawlspace that is super warm, clean, and bright...having been in quite a few dingy and dank crawlspaces, I can say I wish all crawlspaces were as nice as mine. As I said, I am very happy with the results.Good luck!DC

1. 
   jackboy | Jan 27, 2009 08:40pm | #6

   thanks again DC.  I think I'll look around for a deal on rigid insulation.  I know my neighbor bought some cut-offs from some manufacturing company and did the same thing to his vaulted ceiling.  Huge R-value and a deal on the materials.  Thanks. -JC

3. 
   notatexan | Jan 27, 2009 08:47pm | #7

   I'm insulating a crawl space right now (well, after work at my real job) using pink foam.  I'm using 1 1/2" because that fits where it needs to go, and with the money in my wallet I could get the 6 sheets I need (small crawl space, 700 sq ft).  Very easy to install using a jig saw to cut it and PL300 foam adhesive.  I will use tape, mastic, and can spray foam around the rim joist to seal it up.  I think the total cost including foam, sealing tape, mastic, 6 mil poly, can foam will be less than $500.  I am following the conditiond crawl space guidelines from Building Science.  I will also cover the foam with drywall (glued).

   I think the cost will be a wash since I don't have to insulate the floor.  Much better for the house.

   Jim 

   
   

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   Edited 1/27/2009 12:49 pm ET by notatexan

1. 
   jackboy | Jan 27, 2009 11:58pm | #8

   Thanks for the advice Jim.  Think I'll look up Building Science.