First off please dont laugh. I was wondering why they dont use the foam in coffee cups for insulation?? it seems to work great against hot liquid for only being maybe 3/16s or so thick, waterproof… seems like you could mold it into any shape you want. If such a thin cup can protect from such difference in temps more then 1/2 seems overkill… what am i missing here?? thanks in advance…
Frank
We were the winners, cause we didnt know we could fail….
Waylon…
“I was born in the darkest ignorance, and my spiritual master opened my eyes with the torch of knowledge. I offer my respectful obeisances unto him.” Aciores autem morsus sunt intermissae quam retentae. (Freedom suppressed and then regained bites with keener fangs than freedom never endangered.) Cicero, De Officiis ” once i had woman with high hand, and i let her treat me mighty low man, she made a lover of my best freind, and now he treats me like a hasbeen…”
Replies
wyowolf,
Sharp eyes! Good thought, the answer is they do. Basically that's what SIP's are made of.. if you don't know what a SIP is I'll gladly explain it to you.. (no, it's not a small drink) ;-)
yes i do know a little about sips, not a lot, two osb panels and some foam, but it seems like the thickness is more then nessasary , why not put a 1/2 inch around the whole outside of a normal stick built house??
thanks for not laughing...
Frank
We were the winners, cause we didnt know we could fail....
Waylon...
"I was born in the darkest ignorance, and my spiritual master opened my eyes with the torch of knowledge. I offer my respectful obeisances unto him."
Aciores autem morsus sunt intermissae quam retentae.
(Freedom suppressed and then regained bites with keener fangs than freedom never endangered.)
Cicero, De Officiis
" once i had woman with high hand, and i let her treat me mighty low man, she made a lover of my best freind, and now he treats me like a hasbeen..."
That foam, or any other insulating material, offers resistance to the transfer of heat. In a less than perfect way (but useful for discussion) the amount of that resistance is labeled with the R value. The thicker the material, the greater the resistance to the transfer of heat. Of course, there's a thickness at which there's no additional benefit--the cost of the extra thickness would not result in commensurate savings from reduced utility costs.
Remember that with your coffee cup, you aren't trying to maintain the temperature of the coffee indefinitely. It's cooling out the top while you're holding it. It's also cooling through the foam, but the rate at which its cooling isn't bothersome because you're drinking it faster than it's cooling. So there's plenty of heat loss happening, just not in a way that's bothersome.
A pot holder would also protect your fingers, but would be crappy insulation for the house. Drywall would work as well to protect your fingers, but not work so well for insulating a house that's trying to maintain temperatures hour after hour and day after day. A coffee cup has to do its thing for 10 minutes or so.
The houses I design use polyurethane foam, which is about double the R-value of your coffee cup. Tests over the years have lead us to conclude that beyond 4" of foam (3" in warmer climates), there's no net payback for installing that next 1/2" layer, i.e., it costs more than the marginal savings you'd see. But less than that does have payback.
The houses I design use polyurethane foam, which is about double the R-value of your coffee cup. Tests over the years have lead us to conclude that beyond 4" of foam (3" in warmer climates), there's no net payback for installing that next 1/2" layer, i.e., it costs more than the marginal savings you'd see. But less than that does have payback.
I assume your 4" applies only to polyurethane foam? Do you happen to know what the equivalent numbers are for EPS and XPS?
Or are they simply shooting for a specific R value? Is your polyurethane around R6.5/inch? So 4" would be R-26. So they're saying R26 is the point where bang for the buck peters out? I assume they are simply referring to walls and not attic spaces.
WAG for R26 would be 5" of XPS or 8" of EPS.
jt8
"Those who wish to sing always find a song." -- Swedish Proverb
I don't have a recommendation for XPS. We use spray polyurethane, which also gives us the benefit of no seams and negligible air infiltration or moisture infiltration, so I don't know how that compares to other wall assemblies. Sorry. It's more than just R-value, but I don't have a measure of that.Yes, the spray poly is ~6.5 aged. Initially it's ~7.14, but some of the cells open (malformed cell walls, for example) and it loses a bit of effectiveness initially before stabilizing.As to walls v attic, my stuff is continuous from ground up and over (though I distance myself from the term, think "dome") so we don't face the same issues as builders of rectilinear spaces.
thanks, that makes more sense now... so is the blue or pink board the same?? or similar? what about the spray foams??We were the winners, cause we didnt know we could fail....
Waylon...
"I was born in the darkest ignorance, and my spiritual master opened my eyes with the torch of knowledge. I offer my respectful obeisances unto him."
Aciores autem morsus sunt intermissae quam retentae.
(Freedom suppressed and then regained bites with keener fangs than freedom never endangered.)
Cicero, De Officiis
" once i had woman with high hand, and i let her treat me mighty low man, she made a lover of my best freind, and now he treats me like a hasbeen..."
I was wondering why they dont use the foam in coffee cups for insulation
They do. It is called Expanded polystyrene or simply EPS. You can buy it by the 4x8 sheet at Lowes/Menards (white foamboard). It doesn't have quite the R value per inch as XPS (extruded polystyrene... blueboard or pink).
The white EPS also is not rated for external work, so you wouldn't use it on the outside of your basement foundation, but could use it on the inside. But there are exceptions.
SIP's use EPS. Since the foam is sandwhiched between two layers of OSB, it isn't exposed to the elements.
If such a thin cup can protect from such difference in temps more then 1/2 seems overkill.
Your foam cup still gets warm on the outside, that means that it is letting the heat through. Your goal insulating a house is to let the least amount of heat through. You get a certain "R" (heat resistance) per inch. 1" of XPS might give you R-5. 1" of EPS might give you R3 or so. Typically you want a wall with an R of 19-ish, so you would want around 6" of EPS to achieve that. 1/2" would not be enough.
jt8
"Those who wish to sing always find a song." -- Swedish Proverb
Edited 10/9/2007 12:31 pm by JohnT8
>The white EPS also is not rated for external work, so you wouldn't use it on the outside of your basement foundation, but could use it on the inside. But there are exceptions. Isn't that the same stuff used in some ICF's and as the base for synthetic stucco (XPS, too)? I've seen it restricted from internal usage be/c of fumes when it burns, but external?
Isn't that the same stuff used in some ICF's and as the base for synthetic stucco (XPS, too)?
I should have stated that better. What I SHOULD say is that I wouldn't use regular EPS (white foamboard) below grade. It tends to break down over time. But there are companies that make special EPS that is supposed to hold up under those conditions. This company's EPS is supposed to be usable below grade. I believe Mike Smith has used their product, but I have not because it isn't available in my area
http://www.rcontrol.com/
BUT IN GENERAL I would not use EPS below grade unless it was specially designed for that application.
XPS can be used below grade (obviously). Either in its blueboard or pinkboard form (just the same product from two different companies). So that is what I would use around the outside of my basement foundation before they filled it. And what I would use under the slab.
I've seen it restricted from internal usage be/c of fumes when it burns, but external?
You're venturing out of area of knowledge, but my WAG would be that they would require a non-flamable covering on it (like drywall). I wasn't aware that there were areas that completely restricted it. That would be hard on the SIP manufacturers.
I think the spray-on foam would be fantastic, however there aren't too many contractors around here who do it. And the price tends to be rather high.jt8
"Those who wish to sing always find a song." -- Swedish Proverb
> they would require a non-flamable covering on it (like drywall).Yes, it requires a proper covering inside. Didn't mean to imply anything more than that.
Refresh my memory, are you making a sandwhich with your designs; crete-foam-crete, or was it one layer of each?jt8
"Those who wish to sing always find a song." -- Swedish Proverb
One layer each, foam to the outside, mass to the inside.
One layer each, foam to the outside, mass to the inside.
Always good to have heavy duty thermal mass inside to help regulate the temps. no air infiltration, good insulation, good thermal mass = Snug as a bug... as the saying goes.
But if the foam is on the outside, what protects it from the weather?
jt8
"Those who wish to sing always find a song." -- Swedish Proverb
Edited 10/10/2007 11:44 am by JohnT8
Any variety of coatings, from acrylic elastomerics to polyureas to rock veneers and so on.
John,
EPS (or coffee cups) are what have the enviormentalists up in arms.. projected life in a compost heap is measured in centuries.. it simply doesn't break down and decompose. Only two things affect it, UV light and mechanical action.
EPS (or coffee cups) are what have the enviormentalists up in arms.. projected life in a compost heap is measured in centuries.. it simply doesn't break down and decompose. Only two things affect it, UV light and mechanical action.
I beg to differ on this point. What takes centuries to break down are the individual little bubbles of foam. The bond between them WILL break down after a period of time.
I have dug up EPS foamboard that had only been in the ground a couple years, and it was already disintegrating into a pile of little foam bubbles. which might be fine if you were making beanbags, but isn't so hot as foundation insulation.
jt8
"Those who wish to sing always find a song." -- Swedish Proverb
EPS (or coffee cups) are what have the enviormentalists up in arms.. projected life in a compost heap is measured in centuries.. it simply doesn't break down and decompose. Only two things affect it, UV light and mechanical action.
Don't worry ... with the global warming caused by the blowing agent (CFCs) for EPS those landfills will be underwater! ;o)Jeff
JeffClarke,
Most don't use that tecnique anymore they use steam to activate it.
CloudHidden,
yes it is pretty much the same stuff, most ICF's have borate in them to control ants and termits etc.. but they should not be exposed to UV llight which tends to break them down.. once buried it is pretty durable especially if it's been borate treated.. Local code requires a water proofing since it would be possible for water to migrate thru the seams, find a flaw in the concrete and enter your house.. remote but possible..
ok that i can understand, thanks for clearing that up... just a silly idea i had while at work... surfing.. :)
We were the winners, cause we didnt know we could fail....
Waylon...
"I was born in the darkest ignorance, and my spiritual master opened my eyes with the torch of knowledge. I offer my respectful obeisances unto him."
Aciores autem morsus sunt intermissae quam retentae.
(Freedom suppressed and then regained bites with keener fangs than freedom never endangered.)
Cicero, De Officiis
" once i had woman with high hand, and i let her treat me mighty low man, she made a lover of my best freind, and now he treats me like a hasbeen..."
ok that i can understand, thanks for clearing that up... just a silly idea i had while at work... surfing.. :)
My variation on that silly thought occurs every time we get a piece of gear delivered and its packed in a foam block. I think to myself, "gee, if only I had about 200 of these foam blocks, I could insulate a crawlspace with 'em!"
jt8
"Those who wish to sing always find a song." -- Swedish Proverb
One thing to keep in mind is R value is a geometric progression: double the rvalue of insulation, and you cut heat transfer through it in half.
say you have an R2. You just cut the heat loss in Half compared to R1 (no resistance).
Double to an R4; you cut it in half again compared to an R2, but you're only 75% better than R1.
Double to an R8; cut in half compared to R4, 75% better than R2, 87.5% better than R1.
Consider a typical wall is R19, and you'll find that as a percentage, you haven't increased much from R8 (less than ten percent). But as a raw heat loss volume, you've still cut it more than half!
If you've ever seen a heating bill at R19 (this is not scientific, but it illustrates the point), consider doubling it. Is that real money? Probably. Then even though it's only a "ten percent" improvement, that ten percent is still a real volume of heat. Imagine what an R2 would cost if that were the only insulation you had. then add 50% to that, and you'd have your coffee cup insulation performance on a house.
This is not intuitive (though it's not THAT difficult, it's not commonly understood) and that is why some "insulation" manufacturers can make claims like "Reflects 95% of heat" and make it sound really good, when in fact it's not all that special.
Now; imagine your coffee is 120 degrees. Your skin is 83 degrees. that's about a 40 degree difference. How much insulation would it take to make that 140 slow down transfer enough to just feel warm to your hand (say, 110) instead of very hot.... not very much.
Another fun thing to consider. R2 will cut any heat loss in half. If you had something that was 10,000 degrees and something that was 100 degrees, R2 would cut both of their heat losses in half.. even though that volume of heat loss is staggerringly larger for the 10,000 degree object. (Naturally you'd need insulation that could withstand the temperature you were insulating).
That's why you don't need R-10,000 insulation on a space shuttle to re-enter the atmosphere without cooking astronauts, or around kilns to avoid burning down houses. The first few R-value increases do amazing amounts of work there.
Hope that helps! It's fun stuff, I think. Course, I'm biased. And, a big dork. But I'm comfortable with that ;)
-=Northeast Radiant Technology=-
Radiant Design, Consultation, Parts Supply
http://www.NRTradiant.com
thanks to you and everyone for the detailed answers. I really appreciate it. I also noticed the same thing with the sensors i test, I have to have dry ice to test them, for temperature swings from -40 to + 120 for the controls I run. We store the dry ice in blocks in styrofoam coolers like you get at the store, seems to last quite a while and you can barely feel the cold on the outside. was thinking man that would be good for my house :)FrankWe were the winners, cause we didnt know we could fail....
Waylon...
"I was born in the darkest ignorance, and my spiritual master opened my eyes with the torch of knowledge. I offer my respectful obeisances unto him."
Aciores autem morsus sunt intermissae quam retentae.
(Freedom suppressed and then regained bites with keener fangs than freedom never endangered.)
Cicero, De Officiis
" once i had woman with high hand, and i let her treat me mighty low man, she made a lover of my best freind, and now he treats me like a hasbeen..."
> I was wondering why they dont use the foam in coffee cups for insulation??
Duh!! Because then the coffee would run all over the floor.
now thats funny right thar....
We were the winners, cause we didnt know we could fail....
Waylon...
"I was born in the darkest ignorance, and my spiritual master opened my eyes with the torch of knowledge. I offer my respectful obeisances unto him."
Aciores autem morsus sunt intermissae quam retentae.
(Freedom suppressed and then regained bites with keener fangs than freedom never endangered.)
Cicero, De Officiis
" once i had woman with high hand, and i let her treat me mighty low man, she made a lover of my best freind, and now he treats me like a hasbeen..."