SIPS versus Closed Cell versus Dense Pack

[Dutchman]

I recently watched a series of videos on GBA where a Maine Architect (with whom I've worked with) was promoting a project built with SIPS. It's a cool project in Belfast, Maine.

As usual, I began to think of the entire global impact of the effort....I forget what the fancy coined phrase for it is today, but I'll call it that....the entire effort of making the sections, transportation, the erection of them using machinery and the world behind what made them.

Same goes for closed cell and dense pack.

Each approach has it's wear on the environment in some fashion. Is dense pack cheap because it doesn't perform as well (in as thin as an application as the others) as the more toxic stuff, but you need more of it, making it consumptive and possibly as "toxic" as the others? Is closed cell the balance between toxicity, effort and ROI?

Assemblies are all different, have differing time frames, differing labor and different consequences on the environment for what they produce.

Your location may be specific to the best choice, but leave that aside for now.....which one is the best performer for it's impact assuming it was all made in your back yard....sort of, you get the point.

[Dancing Dan]

I can't imagine anyone making the argument for anything but cellulose, Bob. There may be other factors - SIPS allows you to get rid of the rest of the wall assembly, for instance. But we're increasingly getting away from any foams unless except as a last resort, and focusing on polyiso and EPS when we do need them. There's been some good reports on the various blowing agents the foams use - the payback in terms of greenhouse gas potential for some of the foams is in the hundreds of years.

Daniel Bergey of Building Science Corp had a good presentation at last year's NESEA conference on the subject - I have a copy of his slideshow I can get you.

[David Meiland]

Hey Dan, I'd like to have that slideshow.

[Bluewoodrock]

There's been some good reports on the various blowing agents the foams use - the payback in terms of greenhouse gas potential for some of the foams is in the hundreds of years.

There have been some interesting reports, Environmental Building News' "Avoiding the global warming impact of insulation" brought this issue up in June. This article and the presentation Dan is mentioning were largely based on a 2007 paper "Net climatic impact of solid foam insulation produced with halocarbon and non-halocarbon blowing agents". Here is a link to said paper.

http://faculty.geog.utoronto.ca/Harv...nsulation).pdf

Disclaimer- I'm an evil foam guy, bent on world destruction. That being said foams often make sense in a lot of applications and a lot of this anti foam furor smacks of alarmism to me. There are also some valid points that have been made regarding how the article may have some anti foam bias built into the methods used. Here are some links to some differing opinions and discussion on the topic.

http://www.buildinggreen.com/auth/ar...ion-Questioned

http://www.energyvanguard.com/blog-b...t%20the%20Sci]


My point is that foam gets bashed a lot, and while it certainly bears thinking on when and how we use it, it can be an excellent product in a lot of applications.

[Dancing Dan]

And there was an excellent discussion in Environmental Bldg News a few months ago as well - Alex Wilson wrote a piece on the subject, and the following month a foam industry rep wrote a very good response. It's a big, complicated issue that a lot of people smarter than me are working on.

We still use foam - the last house we did we used spray foam on the rims joists, and rigid on the foundation walls and sub-slab. It is largely fantastic stuff that performs as designed. But even if Bergey's conclusions turn out to be overblown (get it - that's a joke!) clearly there are various nasties in the production and installation of foam that aren't an issue with cellulose.

[Bluewoodrock]

And there was an excellent discussion in Environmental Bldg News a few months ago as well - Alex Wilson wrote a piece on the subject, and the following month a foam industry rep wrote a very good response. It's a big, complicated issue that a lot of people smarter than me are working on.

Yeah, one of my links is to the SPFA rsponse and discussion on EBN

We still use foam - the last house we did we used spray foam on the rims joists, and rigid on the foundation walls and sub-slab. It is largely fantastic stuff that performs as designed. But even if Bergey's conclusions turn out to be overblown (get it - that's a joke!) clearly there are various nasties in the production and installation of foam that aren't an issue with cellulose.

Absolutely no disagreement there. Although I did hear about a case the other day of a woman who had cellulose installed in her home in a retofit application. She then developed serious respiratory problems- supposedly she had a reaction to the borates in the cellulose. Not sure if it is true, I heard the story from another insulation contractor ( who does all types of insulation).
Anyone else heard of such a thing? A quick google didn't turn anything up for me, and it may be bunk. Although the guy who told me is usually on the level.

[jesse@kaplanthompson.com]

Here's the graphic from EBN showing embodied energy of various insulations. Cellulose is 2.1 MJ / kg, fiberglass is 28, closed cell 72. That's a huge difference, closed cell would have to be amazingly more effective to balance out that gap, and at R-6 / inch compared to R 3.6 / inch for celllulose, there's no way.

[Bluewoodrock]

Which brings up another issue I have with the article- every closed cell on the market these days (that I know of) is pushing R7 per inch- not a huge amount but it is typically about 15% better than what it's getting credit for there.

Additionally, 4th generation blowing agents, which should be in use within 18-24 months, look like they'll push the R values beyond R7, as well as having significantly lower global warming potentials. Which is also mentioned in the article- they didn't get it all wrong :)

[Dutchman]

Here's the graphic from EBN showing embodied energy of various insulations. Cellulose is 2.1 MJ / kg, fiberglass is 28, closed cell 72. That's a huge difference, closed cell would have to be amazingly more effective to balance out that gap, and at R-6 / inch compared to R 3.6 / inch for celllulose, there's no way.

That is a huge gap.

I guess what I'm curious of is the entire impact from start to finish for each of the assemblies.

SIPS: Glue covered plywood sandwich with foam filler, how much did the OSB kill us, how much did the foam kill us, etc....what was the manufacturing energy used, shipping, and on and on.

Closed cell: Where does the liquid goo come from? energy making it, truck to heat it and pump it, steel (maybe plastic) barrels to hold it and transport it, etc.

Cellulose: Which is/was trees, then it's treated with what from where, it (usually) needs two framed walls to hold it, the netting, the steel staples, the diesel truck to pump it (like closed cell)

[Bluewoodrock]

I guess what I'm curious of is the entire impact from start to finish for each of the assemblies.

That is a valid question, but for me the issue becomes that there are too many variables at play to get a truly meaningful number. I think the natural tendency on these type of calculations is that we have pre supposed idea of what is "best", and we look for numbers that support our side. Numbers feel right, but I'm always reminded of the quote " If you torture the data long enough, it will confess".


Another thought that I have about embodied energy is what is the comparision between embodied energy and energy used by the building over the course of it's service life. I live in a 100+ year old building, it would seem to me that energy use by the building occuants has far surpassed the embodied energy. Of course to calculate the true embodied energy I would have to consider all the repairs and improvements over the years. And where is the line drawn on that, the paint in my living room that has changed color 4 times in the past 7 years cetainly has an embodied energy profile, but where does that factor in. It certainly didn't extend the service life of the building- although it did make my wife happy.

I guess my point is to deem that one building assembly or another is always the right choice, based on some calculations that are full of assumptions, is short sighted. Different assemblies in different locations will require different approaches. And of course the cynic in me thinks that the real problems we face are probably something none of us have thought of yet.

My apologies if this is a rambling, incoherent mess. I'm home sick today and hopped up on an exotic cocktail of cough suppressants and analgesics.

[Dutchman]

Another thought that I have about embodied energy is what is the comparision between embodied energy and energy used by the building over the course of it's service life.

This was my rhetorical question from the start. That same old mantra "you have to break eggs to make an omelette" thing applies here. If I use Ice and Water Shield, which sucks, it will protect stuff for a very long time, which does not suck....same thing.

I'm not necessarily a banner waver of any of the options because I believe they all have their place. My distaste of the foam versions is the impact on the environment part. My distaste of the cellulose option is...is...it's a mess to deal with if you ever have to dig into it in the future.

I asked Jesse to come to my new house a while back when I was renovating to discuss insulation options. During the visit, (previously cellulose insulated) we stood wearing masks outside the door (whilst being demo'd) within a dust cloud of nasty old crap flying around in the air. That stuff sucks to work with after the fact. It seems unmanageable and unpredictable from a renovation standpoint. What I appreciate about it is it's cost effectiveness, and as Jesse also pointed out, it's similar hydrometry to the wood most of our houses are framed with....makes perfect sense....but damn it, without fail, on a 98 degree day, my job is to gut something filled with this stuff....ugh.

If someone could come up with a version that was as manageable, predictable and stayed put, I'd be as happy as could be.

[Dancing Dan]

If you and Jesse had come to the last Building Science Discussion Group, you could have discussed this very topic, you bums. Not only that, you could have drunk beer while you did it, and Mike would have been healthy.

[David Meiland]

How come you guys get to have a local Building Science discussion group?

[Dancing Dan]

We have a critical mass of opinionated insulation contractors.

[Dutchman]

If you and Jesse had come to the last Building Science Discussion Group, you could have discussed this very topic, you bums. Not only that, you could have drunk beer while you did it, and Mike would have been healthy.

"Drank" beer, busting you on that because I have nothing else.....the last few meetings....bummers for me, my absence has been the result of funerals. I think the old folks are gone now, I should be clear for the next few rounds.



How come you guys get to have a local Building Science discussion group?

Because Dan and Maine Green Building Supply (and others) work hard at hosting it....we all love it.