Spray urethane foam insulation

[brookledge]

I know the topic of insulation has been discussed before but I was wondering if anyone has ever used one of those Do it yourself spray foam kits?
I called a contractor that does it and told him I had about 300 ft2 with 2X6 walls and he quoted me about 1,400.00. That is way more then I can spend so I looked online at the DIY kits which are alot cheaper. Also I was wondering if it could be sprayed right on metal roffing from the underside with out causing any problems.
Thanks
Keith

[KenWP]

For the roof what's styrofoam work out to compared to the spray foam. Also are the walls allready sheeted in that you want to use the spray foam.With foam you have to watch for cold spots. There is still some bag insulation on the market that blows in also.

[gmcooper]

From what I remember there are two types of spray foam insulation. Open cell and closed cell. The closed cell guys claimed theirs was better. It should stick to the metal enough as it will also stick around purlins and and studs. Would make a fairly dripless ceiling as well. A friend of ours gave us a price of $2.00 sq ft. some of the guys do a much neater application than others.
Never knew of anyone that used the DIY kits, although several have looked at them.
Good luck