We’ve just finished the plans for our new house. The drawings are done and the engineer’s report is complete. So now I’m starting to look at materials.
I’m really intrigued by the new spray insulation. Can anyone comment on how good it is and is it a worthwhile investment? We will be building just off the straits of Juan de Fuca near Sequim, WA.
Thanks for the help.
Scott
Replies
Urethane is a very effective sealant against air infiltration, and the closed cell formulations are also fairly effective against water. The most common uses for it tend to be around window and door openings, and around here when building a "healthy" home or in more lay terms an airtight home, it is used because it seals everything out. I'f you're thinking of spraying all your walls, I have no idea on price, but I'll be money its more than fiberglass. I'm not aware of any significant disadvantages to the stuff, but if you ask an electrician down the road to drop some new outlets for you, they'll likely have a different spin. You may also want to look into just how airtight this really makes things, as opting for urethane might also make it mandatory that you have a special air pump & filter system to refresh the air supply in the home.
It's not new. Sprayed foam insulation has been used on commercial roofs for 20 years or so. I think it's flammable, so you may have to take that into consideration, and yes, you better get everything inside the walls before you spray, because it's a great barrier for everything.
Of all the things I wish I could have put into my new house, sprayed in insulation would be it. But it cost much more than the others...especially for the DIY'er like me (can't be done by yourself...far as I know).
Very tight, can be put everywhere, all those little nooks and crannies that fiberglass never gets put, or even if it does, air still moves around.
I'm in NY state, and most likely would see the heating return within 10 years or so...but my firewood is free. If the extra cash (maybe $5-10K or so more (??) can be swung, do it. Someday everyone will do it this way...
Today it is considerably more expensive...Others here know much more...and there has been many threads about it.
You can do it yourself. FOMO has refillable kits that are two part Urethane. They have a new product that they claim will not blow out the walls if sprayed into and existing wall. I've used this stuff and am glad I did.
http://www.fomo.com
It's the way to go if you can afford it.
I re-built one on a beach facing the cold - no make that fridgid - NW wind from Canada. No-one wanted to buy it because they knew how cold the location was. Folks from Alaska now own it and swear by how quiet it is and how easy to heat. A storm can be howling and they don't know unless they open the door.
Excellence is its own reward!
Hi piffin, could you please answer one (two) additional question(s) for me?
- Is a vapor barrior still needed with this foam product? If so, would it be the same as with fiberglass?
Thanks.--Solo
Remember, measure twice... then keep cuttin'
'til it fits really fine.
The urethyne foam is a vapor bar in itself. A very similar product was once used as a roofing product because it is waterproof..
Excellence is its own reward!
"The first rule is to keep an untroubled spirit.
The second is to look things in the face and know them for what they are."
--Marcus Aurelius
--So... just repeat several times:
"Don't worry honey, it's not mold, it's the texture of the foam"
I think I'm gettin' the hang of this!
Seriously, thanks for takin' the time.
Happy holidays!--Solo
Remember, measure twice... then keep cuttin'
'til it fits really fine.
Scott:
I'm from Seattle and we used some foam insulation in my own house. It worked great and we're very happy with it.
The stuff we used is called icynene. According to the reps, it's been used in Canada for about 20 years now. It's supposed to be non-toxic, and is not supposed to absorb any water. Thus, it won't develop mold like wet fiberglass can.
The best thing about it for us was that it doesn't have to be vented on cathedral ceilings -- that saved me hours of work of providing stand-off vent channels and vents at the eaves and ridge.
As I recall, the installed price was about $1.50 to $2.00 per square foot, depending on the thickness.
Ragnar
I get the urethyne for about .70/board foot.
Excellence is its own reward!
Thanks much for the information.
The icyenne is exactly the product I'm looking at and I can't seem to find any negatives.
Thanks for your time.
Scott
Ragnar,
I know this is an old message that I'm replying to, but I am considering Icynene for attic insulation for my (1920's, unvented) home and I wonder why it is that vents are not necessary. I thought that vents are to keep the roof cold to eliminate ice damming and to keep condensation from forming on the underside of the sheathing. How does Icynene prevent these issues without venting?
1SOR1,
I'll try to answer your questions the best I can.
I thought that vents are to keep the roof cold to eliminate ice damming and to keep condensation from forming on the underside of the sheathing. How does Icynene prevent these issues without venting?
First, the best way to keep the exterior surface of the roof cold is to isolate it from a heat source. That is, if a lot of warm air is moving against the interior face of the sheathing, it will act to warm the roof. Insulation applied to the roof sheathing will help keep house heat away from the outer surface of the roof.
Condensation forms when warm air experiences cooling. In technical terms, the relative humidity of a given mass of air increases as temperature drops. This is because a pound of warm air can effectively hold more water than a pound of cold air. When the dew point (100% relative humidity) of an air mass is reached, water droplets form and literally drop out of the air.
An example of this is when a car windshield fogs up: as the warm air in the interior comes into contact with the cold glass surface, localized temperature drops and relative humidity increases. Once the dew point is reached, you see fog and eventually water droplets running down the windshield.
When building cathedral ceilings, fiberglass insulation must be vented. This is because fiberglass insulation will absorb water vapor. Warm air from the living space migrates through the fiberglass and toward the cold roof sheathing. If the temperature difference is great enough, condensation may occur -- and it will occur within the fiberglass batt itself. The insulation will then absorb water like a sponge, and mildew and rot may follow.
On the other hand, icynene foam insulation will NOT absorb water. It acts as a vapor barrier in itself. Therefore, water vapor can not pass through the insulation, and will not become trapped within the insulation, as is the case with fiberglass. In the case of a cathedral ceiling insulated with icynene foam, the water vapor in the ambient air simply will not pass through the insulated ceiling. And unlike the windshield example, condensation will not occur on the inner face of the cathedral ceiling since the surface temperature (being thermally insulated from the cold outside) remains warm.
Hopefully that explains the situation for you. Let me know if I can clarify anything.
Ragnar
And I guess condensation can't form on the underside of the sheathing itself because the spray-in foam really doesn't leave any gaps at that point in the assembly...thanks, that makes some sense...
It is often repeated that asphalt shingle manufacturers will void their warranties on an unvented installation - have you come across any exceptions for the unvented installation we're talking about?
I think that the concern regarding asphalt shingles centers around the roof deck temperature. That is, if the rafter bays are insulated, there is concern that temperatures on the roof could get really hot!
From what I've been told, icynene was developed in Canada and has been sucessfully used there for about 15 - 20 years. I live in Seattle and I have an compositionn roof with icynene foam. The point is that in the north, I don't think we need to worry as much about excessive heat on roofs as folks do down in the south.
I can't speak authoritatively on this issue, though, so maybe you could ask some icynene reps, or do on-line searches for articles, etc. Or maybe someone else here who has roofing experience could chime in on this discussion.
Ragnar
Well, I live in the North, too (but on the oppositte end - CT)...thanks...
I conducted a little research about a year ago and found a product called Corbond that had an R-7 per applied inch. Its an expanding foam insulation, too. At the time, I could not find any within 300 miles of my location (Atlanta) and gave up. You may want to give some consideration to it for your application. Its not been around as long as some of the other spray-on foam insulations, but its performance is nice.