[JRP3]

I always liked the idea of the reverse to those blocks: http://www.icfhomes.com/ They look as if they would be light and stack up quickly with no mortar to deal with between joints, and by having the concrete in the middle there is a thermal break from the inside and outside and the thermal mass seems better insulated. I believe they have a much better R value than the center foam blocks you linked too.

[tomofreno]

I always liked the idea of the reverse to those blocks...

Certainly would well insulated, but it has high embodied energy due to fabrication of the foam from petroleum and energy used in making the cement. Also, cement production is a large source of carbon emissions. I like straw bales.

Tom

[Dave Koller]

Originally Posted by JRP3

I always liked the idea of the reverse to those blocks: http://www.icfhomes.com/ They look as if they would be light and stack up quickly with no mortar to deal with between joints, and by having the concrete in the middle there is a thermal break from the inside and outside and the thermal mass seems better insulated. I believe they have a much better R value than the center foam blocks you linked too.

They have worked super in the cold climate up here.... I did something similar in the 70's .. poured the walls and put 2 inch foam all the way around ... less on the inside thus exposing the thermal mass to inside temperature as a buffer.. did that with basement and even in the floor - local cement guys would not pour my floor said the cement would stay too hot... got them to do it anyway ! it never cracked or felt cold - now it is the way they are done except with pex in them for warming the floor.. Still nice after almost 40 years! Lot of 6 inch stick built - with foam on the outside and sprayfoam inside up here - thermal photos show great.. Think long and hard about your windows ... buy the best for insulation value...

[JRP3]

Originally Posted by tomofreno

Certainly would well insulated, but it has high embodied energy due to fabrication of the foam from petroleum and energy used in making the cement. Also, cement production is a large source of carbon emissions. I like straw bales.

Tom

I'm not as concerned with embodied energy in long lasting structures, especially when they will reduce energy usage during their lifetime, which could potentially be a few hundred years. Straw bales are good, though you need a larger foot print to make up for their thickness or lose some square footage.

[Dave Koller]

Just a quick note - I got the new HOME Power magazine - (I sell them in my store - at cost) go look for it at your newstand - "230 top solar panels compared" 2010 buyer's guide... Geothermal lots of great things in this issue....

[dreamer]

Originally Posted by ClintK

The house / solar panels will go somewhere around here...

We're also trying to decide on exterior wall construction... ideas are:
1. 6" studs with lots of insulation
2. 8" CMU (concrete) blocks with 4" studs inside with insulation
3. Insulated CMU blocks like http://www.nltbuildingproducts.com/Q...reteBlock.html

The FAQ for those Qomposite blocks says R16, even though the Main Page says R19. Did you contact them for a cost ? I hate it when manufacturers weasel with statements about how "it requires less labor, so costs are comparable" rather than giving an actual cost. After all, if I'm building it myself, labor cost is zero.

Those Qomposite blocks also appear to be mortared together rather than mortarless interlocking like these http://www.haenerblock.com/haener_direct.html so how straight and level your walls are will depend on how good a mason you are. The mortarless block systems allow non-masons to get nice level, square walls.

Something to consider with any CMU is how much of the house will be underground. By berming earth up to a 3 or 4 foot level around the house, that portion of the wall can easily be R20 to R60 as earth has an R value of 1 per inch and is literally dirt cheap. I'm considering building a house and going with CMU up to a 3 foot level, and then 2x6 wood structure above that. A 2x6 wall filled with cellulose is about R20. Filled with soy spray foam, it's about R30, but about 10x as expensive.

[ClintK]

Originally Posted by dreamer

The FAQ for those Qomposite blocks says R16, even though the main page says R19. Did you contact them for a cost ? I hate it when manufacturers weasel with statements about how "it requires less labor, so costs are comparable" rather than giving an actual cost. After all, if I'm building it myself, labor cost is zero.

I was just posting that as an example - haven't picked out a specific foam/concrete style to go with.