I tried a search, but only found one pertinent thread.
Anyone use it? If so, did you like it?
Do the little plastic do-hickeys end up poking through from side to side and allow any moisture to trickle in?
Seems like an alternative to ICF’s that a mason could easily adopt. Would allow him to quote the job as usuall and then just add on this as materials. . .
http://www.dow.com/styrofoam/na/concreteliving/advtech.htm
http://www.dow.com/styrofoam/na/concreteliving/whytmass.htm
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Replies
I just spoke with them today. Seriously considering it. I like the idea of the fiberglass connectors to avoid thermal transfer. Had considered the welded wire concrete-insulation-concrete sandwiches, but a builder friend said they transfer a whole lotta heat out of the house in the winter. Looking at both the precast and pour-in-place. Trying to find costs, etc.
They replied to my email request for info and forwarded my info to their Regional Sales guy.
I also left a message for my mason today. I will email him this stuff to see what he thinks.
I am building a foundation/basement with 8' walls. That Basement wall exposure will vary from 1' to 4' above grade. The insulation would be nice - as would the durable exterior surface until I can get around to putting on the cultured stone.
I also have a high water table here and don't want to put anything down in the basement that could get damaged by water for the first year. We are taking all precautions and utilizing best practices, but I'd rather be safe than sorry. The problem with traditional ICFs is that I have to cover them with a fire barrier (sheetrock) before I can move in.
This system would get me around that problem.
I will let you know what I hear with regards to cost.
>The problem with traditional ICFs is that I have to cover themNot only that, but a concrete-insulation-concrete sandwich has better energy characteristics than i-c-i (the ICF setup).I spoke with the precast company this morning, and came away extremely impressed! The precast assembly includes all materials, of course, plus conduit, window/door openings, attachments, plus the concrete gets a factory-perfect finish on interior and exterior! We can't match that quality with either poured-in-place or spray-in-place. The assembly is 2" concrete, 2" insulation, 4" concrete on the inside.They also deliver and install!Costs: FOB factory, $10-$12/sf wall area. Delivered and installed 200 miles away, total of $15-$16/sf. For all that's being provided, that seems like a great price.If we turn a critical eye to this assembly, what are the flaws? What am I missing or not asking that I should?
Not only that, but a concrete-insulation-concrete sandwich has better energy characteristics than i-c-i (the ICF setup).
When anyone says that 2" of ridgid foam is better than an ICF's 4", my bs meter starts to chirp. :-)
Beer was created so carpenters wouldn't rule the world.
That claim reminds me of the study done to compare radiant heat to forced air
The stydy built a structure and equipped it with both systems. Ran one for 2 weeks, then the other for 2 weeks, etc. The forced air came out on top for efficiency at maintaining temp for cost.
The forced air system benefitted from the residual thermal mass of the radiant, but the reverse was not true.
Lies, dam# lies, and statistics. . . .;-)
I am guessing that Dow's claim is that the thermal mass of the concrete is in the living area to more readily take up and give up the heat. The Thermal transfer into and out of the storage medium is inhibited by the R-value of the outer insulation with traditional ICFs.
Like all claims, they need some context. This feature is more beneficial in some installations than others. In the (upper) midwest with smaller temp extremes over a 24hr period, I would think that overall R-value of the wall is a better indicator of efficiency. This is purely speculation on my part, though.
The main draw for me is that I can leave it "as-is" after install.
Don, it's not the 4" vs the 2", it's the placement of the insulation. Interior insulation vs exterior makes the difference. A wall with exterior insulation and interior mass will outperform one with mass-insulation-mass, which will outperform one with insulation-mass-insulation according to the people who test such things. The ICF wall would actually be better without the interior insulation, so that it could benefit from the thermal mass.But like jhausch, I also like that you're left with two surfaces that don't require additional materials.
A wall with exterior insulation and interior mass will outperform one with mass-insulation-mass, which will outperform one with insulation-mass-insulation according to the people who test such things.
Why? Please support that assertion.
DG/builder
OK, I'll dig out the report. While I do, a question for you to start:Which wall will perform better based on energy considerations, a wall with 3" of continuous exterior insulation and 4" of interior concrete, or a wall with 4" of exterior concrete and 3" of continuous interior insulation?Looking to see if our basic assumptions are similar or dissimilar. The inches aren't critical numbers in the question...I picked 3 and 4 arbitrarily.
Neither. My assumptions are simple:
1. Under static steady-state conditions it doesn't matter which is on which side. Thermal mass is irrelevant. Only conductivity.
2. The manufacturer cannot know the specific dynamic conditions for a given application. For that matter, they don't even know which is the hot side and cold side. And the hot and cold sides get reversed with seasonal weather. So anytime they start talking about thermal mass in a specific dynamic scenario, the BS alarm goes off.
DG/Builder
This reminds me of a fellow contractor who was getting involved with ARXX ICF construction. He told me (and customers as well) that the R value was 50. The blocks were either 1-1/2" or 2" of EPS on each side. How's that for puffery? From what I found out they used some heating bill comparisons with two similar houses to extrapolate their values.
Jon Blakemore RappahannockINC.com Fredericksburg, VA
Jon, I agree with you. The claims are often ridiculous and not supported by any science or testing. Claims like you mentioned certainly aren't supported by the labs doing building research. Of course, neither are the Dow Corning claims for fiberglass batts.Interestingly, there's no need to makes such hyperbolic claims (maybe the mfg perceives a PR benefit...who knows). When running the numbers through different load calc equations, there's precious little difference between the loads for an R35 assembly, for example, and an R60 assembly. Quickly diminishing returns once you get beyond upper 20's or 30. Air infiltration rates make a big difference in loads, though.Also, the DoE software (ResCheck) recognizes different wall assemblies, but assigns its own values for the "R" of the wall, based on the configuration of the assembly. This avoids the exaggeration of the type you mention. To dg's likely consternation, they do provide for differences based on the presence of mass and the location of the building, and their figures confirm all that we've observed over the years...they appear to have gotten it right without resorting to hyperbole, and that's been gratifying.Now, perhaps DoE is wrong, and the load calc software is wrong, and ORNL is wrong, but until I see better science, I'll defer to them.
Edited 2/15/2006 2:04 pm ET by CloudHidden
Now, perhaps DoE is wrong, and the load calc software is wrong, and ORNL is wrong, but until I see better science, I'll defer to them.
Cloud, I completely agree. My point was only to note that often times claims are made that range from hyperbole to outright lies (or even worse, statistics!) even when talking about industry accepted values (FG=R3.7/inch, EPS=R4/inch).
If DOE, ORNL, or Building Science Corp have a study to back a POV I'm all ears. Oftentimes, though, critical thinking and scientific principles aren't even given a nod.
Jon Blakemore RappahannockINC.com Fredericksburg, VA
http://www.ornl.gov/sci/roofs+walls/research/detailed_papers/thermal/dynamic.html Particularly look to the discussion of Figure 5 and it's chart comparing i-c to i-c-i for different locations.http://www.ornl.gov/sci/roofs+walls/AWT/home.htmhttp://www.ornl.gov/sci/roofs+walls/research/detailed_papers/thermal/index.html"Comparative analysis of sixteen different material configurations showed that the most effective wall assembly was the wall with thermal mass (concrete) applied in good contact with the interior of the building. Walls where the insulation material was concentrated on the interior side, performed much worse. Wall configurations with the concrete wall core and insulation placed on both sides of the wall performed slightly better, however, their performance was significantly worse than walls containing foam core and concrete shells on both sides."All that's from 2001 or earlier.
Nice research work, Cloud.
I am assuming that the various structures have the same static R-value for their walls.
If that is the case, the only caveat here when using this study to compare something like T-mass to tradistional SIP is that the static R-value of the T-mass would probably be less than the SIP due to overall thickness of foam layers. Would you agree?
The other gentleman that made the point about the law of diminishing returns when comparing R-40 to R50, for example, makes a good final point, too.
>The other gentleman that made the point about the law of diminishing returns when comparing R-40 to R50, for example, makes a good final point, too.Absolutely. I do buildings that use about 3" of concrete inside of spray polyurethane foam. A certified energy consultant (I don't know his precise title, but he's one of relatively few certified by Florida to review a building's energy characteristics during plan review) has told me that in southern US climates, there's no meaningful gain in performance beyond 3" of foam, and in northern regions, there's no meaningful gain beyond 4" of foam. One exception is with some refrigerated or food storage applications, where 5" or more still has a payoff.
Looked through the paper you had links to and it's somewhat biased, and downplays the effectiveness of ICFs, especially in colder climates.
How many people are building concrete walls with 4" of exterior foam insulation? 2" is hard enough to deal with as far as the exterior wall details go, so 4" would be interesting.
The charts that compare various towns show Boulder, Colorado results that are very close. No offense to those in Boulder, but it's not really all that cold there.
The simulation also didn't take into account the effect in basements of ground temperature sucking heat from the interior. With ICFs it's limited, but an exposed concrete wall is a pretty good conductor. It's a hard sell to say we need 2" of foam under a slab, yet we can leave an 8' wall of concrete exposed connected directly to the much cooler dirt as a benefit?
I'm not convinced of anything new. Insulation R value is the key in cold climates and wall mass is the key in hot climates. Anyone building a wall with 4" of foam, either outside, inside, down the middle or split will get a thumbs up from me. Unfortunately, very few builders do.
>How many people are building concrete walls with 4" of exterior foam insulation?Me. Well, designing 'em. There is a handful of builders building 'em. Lovely results.>I'm not convinced of anything new. Insulation R value is the key in cold climates and wall mass is the key in hot climates. Anyone building a wall with 4" of foam, either outside, inside, down the middle or split will get a thumbs up from me.Agreed. That and no unplanned air infiltration are winners in my book. It will be nice when the scientific results are voluminous enough to explain all the nuances. Would love to see identical spaces with different wall assemblies lived in by identical families and see what the energy consumption is...
Would love to see identical spaces with different wall assemblies lived in by identical families and see what the energy consumption is...
I must admit that the information on warmer climates was interesting, more interesting that expected. However, the simulations only took into account the thermal mass/heat transfer of the wall systems without factoring in the additional buffering effects of a typical slab. In hot climates an uninsulated slab must have a significant buffering effect. That one addition would even out the field somewhat and be less misleading, or at least more informative as a predictor of real world results.
Nonetheless, I have a little more respect for the importance of interior thermal mass.
Interior thermal mass is also a key element on the many passive solar designs for cold climates, which seem to be creaping more and more into the mainstream.
Maybe one day ICFs will be one sided with all the insulation on the outside and we'll use a traditional plywood form connected to the block on the interior side.
:-)
Fishing was created so carpenters wouldn't rule the world.
Royal Building Systems makes an ICF that is thermally correct.Its PVC with polyurethane insulation only on the outside. Also fully finished if you like PVC walls in your basement.
SOunds interesting - still not sure if my BI would allow exposed PVC in the basement. I would probably have to immediately sheet rock that, too.
Cloud,
Trying to interpret all of the "testing", and more importantly all of the claims, should keep you busy for awhile.
I had given you the http://www.allwallsystem.com website. They seem to have had testing done in Florida to validate your concrete-insulation-concrete theory.
This system appeals to me since I would like to build a retirement home and the speed of erection (dream on DW says) and efficiency, etc makes lots of sense.
Pete
All Wall pulls data from the ORNL site, iir. We have to be careful, lest some of these studies become self-referential. And they didn't compare their composition to an exterior insulation, interior mass wall, which ORNL suggests will perform even better than c-i-c. I'm a bit suspicious of their claims be/c of that bit of conveniently ignoring the data that doesn't suit.But there are two other concerns. First, I can't use a post and beam system to support my structure. I need continuous support. But that's unique to my situation, and not a general issue.The other concern is the effect of the post and beam on the energy usage. They talk about a c-i-c wall assembly, but in fact they don't seem to have one. They have major areas where there's solid concrete. What effect will this have on the transfer of heat? It's gotta be comparable (but worse) to claiming R-whatever for a fiberglas batt, but ignoring the transfer through the studs.For now, we're focusing on the Dow system, and especially the precast, to see where it leads. It has big backing. The engineering they've sent me looks solid. They don't make outlandish claims. The costs appear reasonable. Etc. If anything changes, I'll pass it along.
Speak for yourself "especially the precast". I am looking at the poured in place option :-)
For me, it comes down to the price of the materials, the price of the extra re-bar (layers in both wythes req'd) and how much extra labor my mason thinks it will require.
We'll see what happens
It'd be great if you could share if you ran the numbers. Would love to know the true cost of p-i-p!
Will do - it will be somewhat subjective as it comes down to how eager my mason is to try this out.
Other than the delta in the labor component, I expect rebar cost to go up by nearly 100% and concrete to go down by 25%
Hi Cloud,
I got my ballpark pricing today from the DOW T-mass disty in Iowa (I am in WI). $3.10/squarefoot, delivered to my site. They will pre-make the corners to fit the mason's form geometry. They will also pre-cut the other panels to match the form widths to speed the set up. (or, you can order them in stock sizes and cut on site)
If we go this way, the wall design will be 4"c, 2"i, 4"c. The rep faxed me the set of engineering drawings and that is how it works out. Suprisingly, there is not that much extra re-bar in the wall and the net concrete in the wall is still 8", so I am not sure how much the bid from the mason will change. . .
My design is very simple: 4 corners, 8' walls, etc. The mason seems interested in trying it since this is not a complicated pour. We'll see. . . .
Thinking out-loud here, the 1" foam on my current bid is $16.00/4x8sheet (or $0.50/squarefoot). So, extrapolating, 2" is probably around $1.00/squarefoot. The composite "standoffs" are on a 1' grid, so there are probably 21 per sheet. . . .say those cost $0.50 or so each. . . My mason quoted $46/running foot of 8'x8" wall (footing included). . . So *roughly speaking* I guess PIP costs for T-mass in my area will work out to around to somewhere around $10/sqaurefoot of finished wall.
I will confirm when I get my official bid, but I think we may be able to swing this.
IN case I forgot to mention, I live in a rural area and the delivery is only NE IA to South-Central WI - your mileage may vary.
Based on the studies you've mentioned and the "easy adoption" by poured wall contractors - this seems like a really attractive system.
The company that is really going after this market is Superior Walls.
They are thermally "incorrect" but very user friendly in design.
5 years ago they quoted $85/lf., or $10.50/ft2
Edited 3/19/2006 11:09 am ET by DenverKevin
I'm a designing our "dream home" and seriously looking at Superior Walls. I was impressed by the 5000 psi concrete walls with insulation, utility chases, and metal studs.
What is the basis for stating that Superior Walls are "thermally incorrect"?
Thanks,
Stan in TN
"Thermally Correct" in a heating climate is all the insulation on the outside, all the concrete on the inside. Then any solar gain in daytime is saved for nighttime.
I hope I'm not being a complete idiot here but . . .
I'm in west Tennessee where cooling a house takes up far more of the energy budget (very hot and humid) as opposed to heating (pretty light winters). Then Superior Walls might be less "thermally incorrect" than say in Montana, North Dakota, New Yourk or anywhere with brutal winters, where one is more interested in a basement with more solar gain potential, right? Keep the cool air in in the summer and the warm air in winter.
Actually, the exterior v interior placement of insulation makes even more of a difference as you more south toward areas with daily fluctuations above and below desired indoor temp. Exterior insulation with interior mass works good in your latitude, summer and winter, as a buffer against temperature extremes.
I haven't studied cooling climates enough to be an expert, but the desert Southwest is the only climate to work well with high mass low R walls. (Hence the fat adobe you see)Even there, however, a high mass wall system with insulation on the outside will perform well.
The reverse will perform better.
At any rate, thermal mass, on either side of the insulation, will never hurt the performance of an R-15 wall in a residential usage scenario.The extra cost of interior mass is best justified in a passive solar home and/or in climates with high daily temperature fluctuations around a mean temp. of between 50 and 75.
>The extra cost of interior mass is best justified...And of course, it's best when that mass isn't an extra cost, but serves other purposes such as enhancing the structural integrity of the building and enabling it to withstand more of nature's fury than it otherwise would. These goals are best accomplished as a systematic approach to the whole house, rather than, for example, adding mass ONLY for its thermal benefit.
Here's a few examples of no cost thermal mass, and I'm looking for others as well:1. 2" poured & stained concrete floors using any type of framing system.2. Insulating the top 3'-6' around the perimeter of p-i-p basement walls right up to the sill plate.3. Horizontally laid XPS around the perimeter of a foundation. Depends a lot on the local climate, but it may replace the below grade basement wall insulation. There has been much research on this in relation to Frost Protected Shallow Foundations. To me, it has big potential for a poor man's geothermal heating system when you need only 50 deg. inside, like garages and normally-vacant vacation homes.
If you believe the mass, and the location of the mass to be irrelevant, then we probably can't have much in the way of a fruitful discussion. Perhaps someone else will have the words to explain it.>Under static steady-state conditionsThat's meaningless to me in the context of a building. All my houses exist where there are daily and seasonal variations.>The manufacturer cannot know the specific dynamic conditions for a given applicationSo. We know how day becomes night and exterior temps fluctuate accordingly, and how internal temps will react with different wall assemblies. We know the loads, and verify this with actual performance.But if you don't believe that mass and its location has any effect for a building, then I wouldn't even know where to begin, because anything I cite wouldn't seem to carry any weight.
Go get'em Cloud!
Like you are saying - it has to be taken in the context of a specific application.
A house in AK deals with different daily and annual temp swings than a house in AZ.
In lower elevations of AZ I would think you want to very-slowly gain heat in the day and release it internally at night. Such a design would probably benefit from i-c-i and no south facing windows.
In AK you'd want to quickly gain any heat if possible during the day, but it is more important that little heat is lost during all times. Such a design would probably benefit from c-i-c (or just i-c) and strategically placed south facing low-e windows with insulating blankets that cover them at night.
In the end, like with the R-50 claim by some ICF mfg's, what is the net result of the complete system and how much energy does it take to maintain a comfortable living temp. . .
I hope this can stay uncontentious. I'm trying to word things carefully to avoid any offense.By all accounts, (ok, _almost_ all accounts), mass has greater effect where there are fluctuating temperatures. The further north we head, the less effect is has be/c in winter the sun won't be strong enough nor the temps high enough to fully "recharge" the mass. Forgive any inexactness in the wording...I'm winging a forum post and not writing a thesis.Also by all accounts, intelligence in the placement of windows makes a HUGE difference. One of the reasons I don't do a plan book, despite frequent requests. A good design for one site might be terrible for another, regardless of the wall assembly. But if you get the glazing right, and the orientation right, and the detailing right, then wall assembly will absolutely make a difference in performance.In AZ, I still prefer i-c to i-c-i, because the interior insulation would limit the transference of heat, even when you'd like that to happen. In some i-c houses an acquaintance told me about, someone added insulation to the interior (for sound attenuation re the concrete surface) and found out that their heating/cooling loads increased. I don't have numbers. That one's just a story from a friend. But it's consistent with the science I've seen.I agree that what counts is how the system works in all its elements, and the energy required to maintain a specific level of comfort.
Forgive me for paraphrasing here, but I think i'm in agreement with both sides. Theoretically, the absolute heating load for a given temperature differential should be the same whether the insulation is inside or outside of the thermal mass. However, thermal mass makes a big difference when you account for passive heating, which can play a large part in a house that is well insulated and sealed.One of the questions I have is the value of the concrete outside of the foam that the T-Mass has. Is it as a structural component, or an easy way to make a finished surface? It seems like it could be much thinner than 2" if it was glass reinforced (think wonderboard), but perhaps that would be more expensive than the greater mass of concrete. Interesting technology.Does the precast place cast as long walls or as panels?zak
This article seems to give an answer: http://www.buildinggreen.com/auth/article.cfm?fileName=070401a.xml"When people refer to the “mass effect” or “effective R-value,” they are generally referring to the ability of high-mass materials, when used in certain ways, to achieve better energy performance than would be expected if only the commonly accepted (steady-state) R-value or U-factor of that material were considered."Certainly for any given slice of time, the different assemblies would be identically rated. But as you note, a house doesn't just exist in a single slice of time.The precast walls I'm referring to come in complete walls (up to 40'). That's pretty cool.Why 2" to the exterior? I don't yet know. I just got the engineering drawings today and have not yet reviewed them. Maybe it has to do with embedding the reinforcing steel and connecting that to the fiberglass connector. It's more than required for purely structural reasons, I'm guessing, since tridipanels are usually speced with 1 1/2" exterior and 2" interior, or similar. Dunno, just learning. I asked about more insulation, and the answer was about diminishing returns. I'm guessing they like 8" panels for all kinds of convenient reasons, and everything derives from there. Could be wrong.