Expanded foam attic insulation

[kurt]

Dave, I think you're making the mistake of projecting a lousy application onto the house and extrapolating to it not being a good way to do things.

Properly applied foam is way better than trying to detail everything out with caulks and sealants.

If someone wants to detail away, it's fine with me, but if I had the money, I'd be using foam in a blink.

[David Meiland]

The jobs I see, it's superb as an air barrier.

I don't dispute that it can perform well. I think you would find it very interesting to get a blower door and start checking out houses with it. You already have the IR.

In the long run it seems likely to me that foam will go away. Oil will get too expensive, in fact it appears poised right now to derail the "recovery". Oil at $50-75 per barrel makes for semi-affordable foam. Oil at $200 makes foam way too expensive for most people. Lower-cost details will have to be used to make housing for the masses, which is 99% of everybody.

Here's a piece on fire retardants in foam, another angle worth considering: http://www.ecobuildnetwork.org/the-buil ... -chemicals

[kurt]

Well, now we're not liking it based on prognostication.

Of course oil is going up in cost. A lot. Extrapolating from that to foam's demise is specious reasoning.

Everything has gone way up in cost, except maybe drywall. That hasn't stopped houses from being built.

People will base house construction choices as they always have.........expedience and emotion tempered with economic benefit.

Foam is not going to go away. It will get more expensive, people will use it, and the other options will remain for those that can't afford foam.

[Tom Raymond]

Not all foams are oil based, there were at least two companies at the IBS promoting vegetable based foams.

So as not to leave out the fiber guys; there was also a company making all manner of building components, including insulation batts, from recycled cardboard and hemp. I like renewables, and while using food crops to reduce energy consumption makes far better sense than using them for fuel, I'm pretty sure insulation contractors smoke enough hemp products.

It is precisely the rising cost of energy that has driven the use of foam insulation, as well as alternative chemistry to make it. As oil and other fuel prices rise energy efficiency becomes increasingly important. Foam is here to stay.

[Chad Fabry]

I think that blown fiber in those walls is going to be a better choice. Batts laid against lumpy SPF are going to have air gaps all over the place.

Of course the entire premise of fiberglass and cellulose insulation is to create dead air pockets- or are you suggesting that the irregularity will create convective paths? If so, I'd bet you're wrong.

[hausdok]

I dunno,

I'm kind of in David's corner. I think that with some carefull air sealing one can insulate a home wiht cells very effectively and at far lesser cost.

One guy that's been a strong advocate for cells over the years is Fred Lugano. Fred wrote some articles for FHB and Home Energy magazine years ago that some of you might find interesting.

Here are the links:

http://www.homeenergy.org/archive/hem.d ... 80508.html

http://www.wag-aic.org/1999/WAG_99_baker.pdf

ONE TEAM - ONE FIGHT!!!

Mike

[primitivelamps]

Good article on cellulose.

http://bct.eco.umass.edu/publications/b ... rt-choice/

[kurt]

I don't think anyone said cells is going away. It's great stuff. It's just not as good as foam, and it requires competent and skilled practitioners to detail satisfactorily, and we all know what happens to building practices that require skilled and competent practitioners.

When they finally legalize hemp, there's a never ending source for cheap resins that make foam.

So, my money is on foam for big picture building. Cells will hang around too, but will be the second choice.

[David Meiland]

Call me two-faced, but when I get around to remodeling the interior of my place, I'm probably going to use Corbond. I have 2x4 walls. The exterior is completely done, so there's no way to add foam over the sheathing, and the interior is too small to want to lose floor area to foamboard on the inside of the studs. One of my neighbors recently dropped $70K on a foam truck but is apparently still fumbling with it. Maybe they'll get good enough to do it right. Option 2 would be foil polyiso cut and fit.

Since I've already been accused of specious prognostication, let me take it a step further and predict the next 5-10 years. We now have code requirements for blower door testing in some jurisdictions, and if the 2012 IECC gets widely adopted we'll be looking at 3 ACH50. That is going to cause builders to learn to air seal their houses in a big way. At that point, anyone who thought that foam was necessary to get a tight house will have an opportunity to rethink.

I'm all for the hemp stuff. I looked into Bio-Based for one house but it's mostly petro, the bio component is very small.