Welcome to the DoItYourself Forums!

To post questions, help other DIYers and reduce advertising (like the one on your left), join our DIY community. It's free!

spray foam insulation vs. R-30 rolls

84EdH's Avatar

Join Date: Dec 2008
Posts: 178

12-10-10, 07:55 AM   #1  
spray foam insulation vs. R-30 rolls

Hi, I have a 3 to 4ft high crawl space under my kitchen and laundry room. the area is about 20x24. There are 2x10floor joists with R-19 faced insulation now. Some of the insulation is falling down, and I need to do some baseboard heater piping under there which means more insulation will have to be pulled down. I am trying to get help on what I should put back up.

I see there is R-30 insulation that will fit that joist depth available, and I have seen on t.v (holmes on homes) that there is spray foam insulation.....which looks way easier. Anybody know what the R value is on that foam and is it reccomended?

thank you in advance


Sponsored Links
Gunguy45's Avatar
Super Moderator

Join Date: Dec 2007
Posts: 20,656

12-10-10, 08:17 AM   #2  
Spray would be the most efficient...but it's pretty costly. The kits you can buy start at around $500 I think and you would need to buy the chemicals.

The one problem I see with it is when it's time for a pipe or electrical repair.

"I sometimes wonder how some people ever made it to adulthood..."

84EdH's Avatar

Join Date: Dec 2008
Posts: 178

12-11-10, 05:15 AM   #3  
thanks for the advice. I did check out a local company....$1300 for 5" thick on a 15 x 15 space. I think r 30 rolls will be fine..

GBR in WA's Avatar

Join Date: Mar 2009
Posts: 1,167

12-16-10, 07:49 PM   #4  
You know the R-30 rating is in the lab with all six sides covered and no outside air touching..... I'd add some rigid foam board to protect the joist bottoms or at least some house wrap stapled to sill sealer on them first: BSI-009: New Light In Crawlspaces — Building Science Information


Bud9051's Avatar

Join Date: Oct 2008
Posts: 9,768

12-17-10, 08:25 AM   #5  
If you watch some of Mike's (Holmes) shows, you will see them using a mineral wool, much denser than the typical fiberglass. I would still cover it down there as Gary suggests and in my experience I suggest something substantial that can stop critters. All of that insulation makes great nesting material, so either mouse proof the area or seal that insulation.


Search this Thread