Can One Insulate the EXTERIOR of a Roof?

[oosik]

Well - I can speak to ONE downside. Don't get so busy that you back off the eaves and fall. Fortunately - that was 38 years ago and I was a whole lot more limber. But dam - it still hurts.

I have a big 'ol Hunter ceiling fan in the living room. It keeps things even temperature at the lowest speed.

 

[radios1]

you can use fire retardant spray foam inside the attic!. Foam it Green 22 Spray Foam Insulation Kit | Fire Retardant

 

[Industrial Toys]

I spoke with an insulation contractor last week. He says, there is STILL no fire retardant spray foam, only coatings to go over it.

Would 2" of SM at R10 even be worth the cost?

Does foil lined foam make a big difference?

 

[radios1]

I spoke with an insulation contractor last week. He says, there is STILL no fire retardant spray foam, only coatings to go over it.

Would 2" of SM at R10 even be worth the cost?

Does foil lined foam make a big difference?

that HE knows of, yet, the company that I linked to DOES sell it, call them and ask them about it!..

 

[oosik]

From a fire standpoint - I doubt the foil wrapping on the RMax will make much difference in a fire. From an insulation point - no idea. The foil wrap protects the hard core foam from mechanical damage and provides a surface for the stenciling of the product name.

 

[Industrial Toys]

They don't say much about the fire rating. I don't want it to burn, period. Of course, having 2" of foam on the outside, wouldn't be much of a picnic if it caught fire either!

 

[oosik]

Around here the "fire" I most worry about is wildfire. Only once in the 38 years here. Five year ago a wildfire got right up next to my West property line. My house is on the extreme east side of the property. But this wildfire - Strawberry Hill Wildfire - brought the dangers to an amazing reality. It also made me realize that no amount of clearing would be of any value. The wind that drove this wildfire had "fire bombs" dropping and catching fire a quarter mile ahead of the main fire.

It was only the local farmers - their large tractors - massive disk harrows that brought this fire under control. All the dedicated fire fighting equipment was already over in the Wenatchee National Forrest. Fighting massive wildfires there. The late summer/early fall five years ago turned into H*LL on Earth for wildfires.

The entire West coast from southern British Colombia to Northern CA was on fire. And as far East as northern Montana.

 

[Industrial Toys]

One of the few reasons, I am not so sad to get rid of the cedar roof.

 

[Topzide]

What about sandwiching the foam board between some drywall? Years ago when I was framing homes for a living, we used 2 1" thick sheets of drywall between townhomes for fire protection between units. You could use 1/4" thick to keep weight down. Foil lined foam helps repel heat transfer. Hope this helps.

 

[Tractor Seabee]

SM is a pretty strong material. Can one not just strap it and put the steel sheets on top?

Glue the foam board to the wood substrate. The metal roofing will have to be held down with a concealed clip system with screws down into the underlying wood. As Oosik said it is a tried and proven system and he has further proved it. Even with furring strips under the SM the clips will still need to go to the wood substrate. Uplift is more powerful than you can believe in a wind storm.

Ron