Expanded foam insulation

[TNHermit]

is anyone here big on expanded foam insulation . Have any clue as to cost or Can give me some hooks into suppliers for a LOT of it. 4-5000 squ ft

[Robotron]

Average costs are at least $1.00 per square foot per inch. Expensive but can be worth it if only trying to seal up a building. Then one inch usually works.

[unioncreek]

Most contractors in my area recommend 2 inches of foam to seal the building and fill the rest of the cavity with fiberglass.

Bob

[Ross]

If you're insulating a rafter roof its pretty hard to beat filling the cavity with foam. Headers too. Around here you can't buy the components to do a big job but a small job is not too bad..... though it's still darned expensive!

[orionrising]

First you need to know what you really want.
There are two main types of foam, open cell and closed cell. They have different properties and uses.
Secondly you really need to consider air flow, condensation and mositure as it is local to your climate. You do not want to create mold issues down the road.
If you do the foam/batt method mentioned above be absolutely sure the condensation point will not be inside of the batting without proper vapor barriers.

[Bentley]

I built a new home two years ago and used the spray foam insulation for all outside walls and roof. The house is aprox 2350 heated and the cost was just under $6000.00 turn key. The walls were 2x4, and we filled the cavity completely with Foam, then Sheetrock on the inside, and 1/2" plywood on the outside with another 3/4" of foiled faced foam board over the plywood.

The roof is regular composition shingles over 15# felt over 5/8 plywood, with the 2x8 rafter bays filled with foam.

All foam is open cell. Closed cell should not be used in closed wall applications because of having 2 separated vapor barriers. Cosed cell has a natural vapor barrier as it cures, and then Sheetrock or other painted surfaces serves as another vapor barrier. Over time, moisture can be trapped between the two barriers, and contribute to mold growth.

FWIW, my electric bill runs $75, to $125, and my nat gas runs $25 to $45. When electric is on the high end, gas will be lower and vice versa. This gives me a very predictable utility cost of less than $150 every month.

Insects cannot get in because the walls are all sealed so well, and the home is very quiet.

If I build another home, it will use the spray foam again.

B

[Darren]

If you're planning on DIY, Google FOMO, the maker, and their product Handi-Foam. It's available in several two component package sizes such as 26.4, 41 and 115.7 lb sizes. It's available from lots of sources including Farmtek, Graingers, MSC Direct, etc.

[TNHermit]

Thanks guys. Will be checking things out. Especially the vapor barrier thing as that is what most concerned me as well as air exchanges