Hey all,
Back to ask more questions about my still uninsulated 1 1/2 story house in Oregon. I got some advice here about ways to insulate the cathedral ceiling in the 2nd floor and I’ve now even got a quote for open cell (Demilec Sealection 500) foam sprayed at 3 1/2″. It’s not too bad (~$3k) but I just don’t think I can swing it right now.
My question is if I opt to skip the foam right now on the underside of the roof deck and blow cells into the rafters above the 1st floor (leaving the 2nd floor still unconditioned)…would there be any big problem coming back in a few years and finishing off with the foam on the roof?
I know this would create kind of two different conditioned spaces so I’m wondering if people have had experience with this or some opinions? I’m really partial to the foam, but I don’t think the finances will allow right now. But I also need to get some insulation in this year and I figure I can blow almost 12″ of cells for easily less than a third of the foam cost.
We are only using the attic for storage now, but looking forward we would like to have some real living space up there. Is this a reasonable temporary solution?
Thanks!
Replies
http://www.sealection500.com/dem/s500/index.php?mod=section&id=4%23top
I had not head of this brand before so I Googled it up. It sounded like a lot of money to me foe just only a ceiling addition roof!
Anyways, there are some interesting things I see that leave me especially unimpressed relative to that cost! First it is rated at only R-3.8. That is only marginally better than denspak cellulose to begin with. One of the greatestadvantages of foam is that you can get up to R-7 per inch with a good polyurethene foam like Corbond.
This company claims the foam to be an open celled polyurethene, but most of those are closed cell, so there must be something different in the way it is formulated. Another advantage of closed cell foams is not only the superior R-rating, but the VB factor that comes with it
3.5" thick at R 3.8 means you would only have a ceiling insulated at R13.3! You should be aiming for R30 at least.
Four inches of Corbond at R7.1 would give nearly that and would perform above that relative to FG batts.
Cellulose at R3.5 x 12" would be insulating you at R42
Are you otherwise ready for insulation upstairs now? wiring etc? if so, just have the place done with blown cells or BIBBs now would be my choice.
But if you have reasons to keep the heat down below for now, insulating htat floor space that way won't hurt a thing, and eventually if you move up above, it will help deaden sound between floors to some degree.
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Thanks for the reply, Piffin. From talking with the installer, it's basically the same product as Icynene. The guy told me that the chemist who created Icynene sold off the rights, then changed the chemistry just enough to be able to market the Sealection 500 as another product. So it should be very comperable to other open cell polyurethane foams like Icynene.In terms of R-Value that is certainly a concern. Closed cell is kind of hard to find around here (only a couple of installers in Portland), but the rough estimates that I got were almost double the open cell quote which puts it way out for payback costs. BTW those quotes do include all the roof deck and the walls in the 2nd floor (only about 500 ft2 of walls though). That just doesn't seem like enough R-value even accounting for the superior insulating properties of the foam.It sounds like a sound plan to just get the cells installed for 1st floor comfort and then figure out the 2nd floor later. Thanks for the tips!