Discussion in 'Insulation and Radiant Barriers' started by nealtw, May 30, 2013.
Nice backgrounder on foam .... best overall bet? Closed cell 2-pound?
We're seeing new companies start up here now that more people want it. The few that I have talked to, seem only to have one product, which is of coarse the best only product you want to use. I guess we need a test of some kind so we can determin if they know there stuff or just sales people.
Good read and great video.
I’m shortly going to be in the process of sealing up and insulating the kitchen I’m remodeling in my old house. It would be great to have a pro come in and spray the project but that isn’t going to be in the budget. The house has some fiberglass and some blown in now and I will be adding back in insulation where I can that suits best.
I have been thinking about a process I haven’t seen done and it will be more DIY friendly than shooting foam, but may have some of the benefits of foam and I was wondering what some of you think of this method. Spraying foam works as both insulation and also a sealing method as pointed out in information above. For the DIYer sheet foam is much easier to work with but the gaps in fitting it allow air flow. My tentative plan is to use sheet foam cut to fit leaving some gap. I will then fill the gaps with can spray foam. The cans are coming down in price and with just filling the gaps rather than the cavity a can will go a long way.
So can I get the benefits of foam and the ease of DIY with this method?
SPF has its applications and is a great turn key option if you want your air barrier and insulation layer in one shot.
There are ways to insulate and seal without using it as well.
Closed Cell (2lb) is good but expensive. There are also some concerns that should be noted when it comes to off gassing with these materials and especially cc SPF.
"My tentative plan is to use sheet foam cut to fit leaving some gap. I will then fill the gaps with can spray foam. The cans are coming down in price and with just filling the gaps rather than the cavity a can will go a long way.
So can I get the benefits of foam and the ease of DIY with this method? "---------------- yes, you can get close to the same in both air sealing and thermally. Keep in mind that exterior foamboard is better in that you control condensation (with thickness of f.b.) and air seal with tapes/mastic, and also eliminate the studs thermal bridging possibly reducing the total R-value;chart; http://bct.eco.umass.edu/publications/by-title/insulating-on-the-outside/
Exterior foam benefits; http://www.finehomebuilding.com/how-to/qa/foam-sheathing-inside-or-out.aspx
http://www2.dupont.com/Tyvek_Weathe...rior Insulation Building Science Bulletin.pdf
We see the boys around here seal the edges with caulk, just not sure what they are using.
Thanks Gary and Neal
I thought about some kind of caulk as Neil suggested but that seemed to require a pretty close fit on the foam pieces. I thought the expanding spray foam would be more forgiving and glue the cut foam in place also.
Going exterior would be great but on an existing house even when re-siding would be a lot of work with windows and doors. I can see with new construction and calculating it all into the design would be a great system.
I will try and take a few photos when I get around to it. Still have a lot of wires to run first.
I would think a closed cell spray would seal it up.
The only reason I would recommend open-cell over c.c. in a can, is that open will have more "give" for the seasonal changes solid lumber (not engineered) moves with humidity changes, (initially, when new) pp.51; http://books.google.com/books?id=iw...um=3#v=onepage&q=cutting floor joists&f=false
Though you still get movement over the years, just not as much. C.c would not have the movement o.c. would, or especially caulking, breaking the bond letting basement/house air get to the rim to condense. Rim RH= 4-16% annually; http://www.paintsource.net/pages/solutions/new construction/wood_shrink.htm
Gary; So it could be backed up with poly and acoustic sealer so if it does break loose, you might loose insulation value but the moisture is still under control.
I think it is a lot of hype personally. Roxol is better fire and sound resistance. It is easy to remove, it also breaths well, foam has air but does it breath? Foam can be annoying to work with and repair later, removing it is difficult, i use it sparingly. To fill in gaps it is priceless, but to do you house with it is just expensive hype.
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