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Dear All: A very interesting website you may want to vist regarding insulation. Is, www.monolithicdome.com I helped built one of these homes in Italy TX, and I’m completely sold, hook line & sinker. The energy efficiency, sound-proofing, ease of construction & sheer strength of these structures, is nothing short of astounding. I am working toward building retirement apts’ & condos’ with 15-16 apts, per dome. Have a good visit. Brian (Tankless)Wood.
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Let's have a discussion about the "superinsulation" movement that began in the seventies.
What are the practical (or not so practical) limits of energy conservation in contemporary building practice?
What is the current state of the art? What is even newer or more radical than the current state of the art? What are the drawbacks?
What are some good resources for those interested in learning about it?
*I'll start. I've ordered William Shurcliff's "Superinsulated and double-envelope houses" from Barnes and Noble (it's out of print, but they have several used copies available).While I wait for it's arrival, can anyone else recommend some good written resources?A pre-emptory note:This is not intended as a "set-up" for GeneL. My apologies in advance for only having questions about this topic. I'm hoping to learn something from the generous folks who frequent Breaktime. Someday maybe I can reciprocate on topics that are more up my alley. I'm pretty knowledgeable about restoration carpentry.As ever, looking for verifiable data,Steve
*To start with the "I can't afford it" end of the technology, an insulation of about r-50 per inch is now available.From the practical end, I usually build with TLI's or other wood I-beams as wall studs with cellulose insulation (not DP yet) and a poly vapor retarder with caulked seams.
*Steve,The book that you ordered is pretty good, I looked at it in the library about 10 years ago. I never liked the double envelope houses for several reasons.1. Fire spread2. A lot of wasted space from the thick walls (much more than double wall) 3. Window framing problems4. ComplicatedI try to go with an insulation that is low in cost as far as $/R/sq. ft. and a wall with minimal thermal bridging thick enough to get a true R30 or better. I would like to compare that to a thinner wall with PUR and no vapor retarder but in my area the only installer is so expensive that a welded titanium vapor barrier installed by football stars on double time would be cheaper. Here the added square footage doesn't even come close to offsetting the cost. In other areas I would like to see prices.I would like to see a factory built Larsen Truss, it should be less expensive than the TJI's that I use.Ron
*I just got a bid for spray PUR in Wisconsin to spray all the exterior walls (including attic walls, garage walls, etc.), spray all the rim joists and also to do all the spot sealing (windows, doors, other wall penetrations, etc.). For a 2800 sq ft, 1 1/2 story house it was about $2000 for 1/2" PUR and about $2300 for 1" PUR. It ends up being about $0.60 per sq ft for 1/2" (R-3.5) and $0.70 for 1" PUR (R-7) for exterior wall space.It is not cheap but it appeals to me because it should provide a very good air barrier, it preserves a normal wall width (no extended window and door jambs needed), it seals behind all electric outlets and it is quick and easy to install with minimal disruption to other subs. It doesn't address the thermal bridging issue though.
*Jim,I understand the sealing effect and like the idea but what studs at what spacing, are you going to use standard or less than standard amounts of studding...and what insulation will you use besides the pur and how much pur, $2000 worth or more. How much will all insulation cost and how many feet in your home and how many floors...Near the stream and needing much more info to yak,J
*Thanks Jim,Any idea how much to allmost fill the cavity (so there is no excess to trim) or to fill it compleatly and trim it flush to the studs?Ron
*Rochester, NY 3 1/2" thick, $3.76 psf of wall.-Rob
*I don't know what the cost would be for a total cavity fill installation but my bid added about $0.10 per sq ft for an extra 1/2" PUR. Extrapolating this to 3 1/2" would end up at about $3.20 per sq ft wall space for 2x4 walls.I am actually using 2x6 walls at 16" OC (I realize that 24" OC would add about 3-4% more insulation but it was too tough a sell to my builder). I will use 1" PUR and the rest of the cavity filled with R-21 HD fiberglass. The fiberglass HD is about $0.50 per sq ft + installation so my total wall insulation will be about $1.50-$1.70 per sq ft with a total true R value somewhere in the low to mid 20 range with excellent air sealing.I think the spray PUR is fairly reasonable for a high end insulation job. The cost for rigid foam is about $0.25 + installation which would end up at pretty close to $0.50 per sq ft. I considered DP cells but no one around here does it and it is somewhat of a challenge in new wall construction.
*Thanks Rob,Is that a "nominal" fill or an overfill and trim?Ron
*Dear All: A very interesting website you may want to vist regarding insulation. Is, http://www.monolithicdome.com I helped built one of these homes in Italy TX, and I'm completely sold, hook line & sinker. The energy efficiency, sound-proofing, ease of construction & sheer strength of these structures, is nothing short of astounding. I am working toward building retirement apts' & condos' with 15-16 apts, per dome. Have a good visit. Brian (Tankless)Wood.