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what is the best material to insulate your walls with? does styrofoam work well for keeping your house warm? Answered

I have thick brick outside walls that will freeze in winter. I want to cover them with wood and some insulation material from the inside, hoping some of the heat from my oven will stay in the house. I can imagine styrofoam would work -which would be nice because it's cheap-, but i've never tried it. glasswool is too nasty, I'd rather not get into that. does anyone have experience with this?



8 years ago

This is a couple of months late but maybe it will help someone.
 1st off, if your renting and don't want to spend a lot of money, take a trick from the OLD OLD days and hang quilts on the walls, they used decorative tapestries but those are expensive, you can get quilts in many designs so they could even be decorative.

 My home is cinderblock with no insulation to speak of,(1950's era florida track home) I glued the rigid foam panels, mentioned previously, to the walls and then glued cheap paneling backwards to the foam, taped and spackled the panels like normal drywall then painted the walls. Each room cost about $80us, remember you only do the exterior walls, and it also helps with the cooling in summer

Ideally, a High R-value spray on foam would be applied to open stud work installed first, then trimmed flush and paneled over with drywall, wood, etc. Foam sheeting is a reasonable solution as well, They sell it in at least 2 inch thick sections at the local Home depot and Lowe's, should be available at most builder's supply houses. Make sure an air gaps have been caulked inside and out prior to closing in the wall. Air entrainment is one of the big offenders to heat loss and especially to the noticeable discomfort caused by drafts..

*quick correction: 3rd paragraph: Make sure ANY air gaps have been caulked...

FWIW, I'm not sure how many square feet you plan on insulating. If it's a big job, I'd consider calling on the professionals to install foam. The stuff isn't cheap, by a long shot. Well worth every penny, but only if it actually makes it into the wall and does so uniformly, thoroughly, and economically...If you've never laid expanding foam, you could end up wasting alot of product by over-filling or fail to seal the space properly by under-filling.

If it's a big job and you're dead set on D-ing.I.Y., consider those 1" and 2" thick foam insulation sheets. If they're installed well (cut to fit snug in the stud spaces, they'll do a great job. not as well as the spray but a helluva lot better than nada, and with a lot less fiberglas to get in your skin and lungs.

thanks for the help, and so quick!
since i'm neither rich nor planning to grow old in this house, probably won't start with the spray, though it sounds like fun
those foam sheets sound great, but i've never seen them in my hardware store.
is it the plastic stuff you can get in big blocks for coushions etc?

The material I'm talking about is usually available from stores that offer building materials. Home Depot. etc. It's specially made for insulating the home. It's usually blue or pink in color, and it has the consistency of dried out marshmallows, if that makes any sense... Like puffed chalk

It's light and cuts easily, but it's not that stuff you get in shipping cartons. It's not the same as the foam that goes into cushions either. Regular foam is a really bad idea for insulating. It's usually highly flammable, and it produces toxic fumes when heated or burning. Packing and cushion foam also don't in general insulate as well as foam insulation.

A 4'x8' of 2" thick insulation foam costs ~$30.


8 years ago

Check out my Instructable! But, in your case, I think the best solution is to use the spray-on foam insulation that seandogue suggested. It can be bought in a kit from big hardware stores. You get a cylinder of foam and a spraygun. You'll need full-body coveralls and a good respirator, too. You start by building a frame wall a few inches away from the brick (so that the cold isn't conducted through the wood), then spray the foam onto the brick. It expands like crazy. Then just cover with drywall! It's a messy process but it's the best solution in your case, I think.

wow that is the longest instructable i've ever seen
i hope my room won't be such a huge project as yours, but thanks alot for the input

 Thanks!  It took a long time to write it, and I could have written more!

Styrofoam, per se, is a fire hazard. There are other foams which are safe and sold for the purpose.