Curious how the concrete core is affected by hot humid climate temperatures. Looked for some real world test but no luck finding any.

Reason I'm looking into this it seems to me to protect the thermal mass concrete core you would want a higher percentage of the foam on the exterior. The more foam on exterior should help the core to be more stable reducing the amount of heat or cold energy being absorbed externally.

Since I live in the state of Georgia will most likely go with Nudura + and wondering if it there would be any value in going with a 3 5/8" / 6" / 2 5/8" wall configuration.

Would love to see test showing temperatures throughout the wall assembly components using different thickness of foam on exterior.

Thermal mass inside the EPS has little or no effect. That's been hashed over here ad infinitum. We believe in keeping it simple. In Georgia, you shouldn't need to use anything more than the standard 5" of EPS insulation. My opinion.

Posted By BrucePolycrete on 19 Feb 2014 04:32 PM
Thermal mass inside the EPS has little or no effect. That's been hashed over here ad infinitum. We believe in keeping it simple. In Georgia, you shouldn't need to use anything more than the standard 5" of EPS insulation. My opinion.

Crap! I sure didn't get to less then 8 btu's per square foot of heated space with just the R20 that some would like to ascribe to 5" of eps. I can't say how it works in a cooling dominated climate but in a minus 32 C design temp climate it does much better then that so if that not the result of an insulated mass, I sure don't know where the extra protection is coming from!

The way I'm looking at it is you only have one chance to build it right and we will most likely retire there also. I haven't drawn up the house plans yet, but I have it in my head and would say by the time I deduct openings and some inset walls above which I plan on being 6" or 8" metal skin SIP my Square footage of ICF wall should be around 3,000 facial feet. So I should be looking at about a extra $1,500 to add a additional inch to the exterior. Would love to put even more on the exterior, but I think it would be wiser to put that cash into better windows.

If you consider your interior temps staying a contestant 70 deg. and exterior conditions during the summer climbing up to 95...98 deg I would say the core would benefit quite well with the extra protection given by an additional inch of EPS. The more heat or cold energy that reaches the core would obviously raise or lower the core temp affecting the interior wall surface temp. The energy that has been stored in the core from the earth below and HVAC system would be less affected. To what extent who knows....

As for ROI I guess that would be rather difficult to figure out as how it affects the thermal mass is hard to calculate? But I guess knowing I have 1" more EPS than most builds here in the southeast, should make me feel better

Have someone who understands ICF run your design with the different scenarios...I think you will be surprised by the poor ROI that extra 1" of foam is going to provide.

Maybe so Chris ..... Will look at upgrading to triple pane windows also.... not that they have a better ROI or that $1500 bucks will go far towards triple pane.

A example of a good ROI....... since the home will be position about 30 deg south west, just planting 3 or 4 trees on south west side will give me one heck of a return in 10, 15 years.

I will have it all sorted out before I draw up the plans and commence construction.

Posted By ricky_005 on 19 Feb 2014 04:02 PM
Curious how the concrete core is affected by hot humid climate temperatures. Looked for some real world test but no luck finding any.

Reason I'm looking into this it seems to me to protect the thermal mass concrete core you would want a higher percentage of the foam on the exterior. The more foam on exterior should help the core to be more stable reducing the amount of heat or cold energy being absorbed externally.

Since I live in the state of Georgia will most likely go with Nudura + and wondering if it there would be any value in going with a 3 5/8" / 6" / 2 5/8" wall configuration.

Would love to see test showing temperatures throughout the wall assembly components using different thickness of foam on exterior.

How much have you searched on GBT? This topic has been discussed quite a bit the past several years. Here are some threads and one article. Somewhere in one of the discussions are some charts showing what the impact of the distribution of insulation outside and inside of the concrete is in relation to climate.

http://greenbuildingtalk.com/Forums/tabid/53/aff/4/afv/topic/aft/79706/Default.aspx

http://www.greenbuildingtalk.com/Default.aspx?tabid=53&aff=4&aft=28658&afv=topic

http://www.greenbuildingtalk.com/buildcentral/icf/benefits.aspx

http://greenbuildingtalk.com/Forums/tabid/53/aff/14/afv/topic/aft/82174/Default.aspx

You can find a bunch more by putting this into the Google search box: thermal mass icf site:greenbuildingtalk.com

Posted By ricky_005 on 19 Feb 2014 10:50 PM
Maybe so Chris ..... Will look at upgrading to triple pane windows also.... not that they have a better ROI or that $1500 bucks will go far towards triple pane.

A example of a good ROI....... since the home will be position about 30 deg south west, just planting 3 or 4 trees on south west side will give me one heck of a return in 10, 15 years.

I will have it all sorted out before I draw up the plans and commence construction.

Size of the windows is important, even more so than triple pane vs. double pane. Heat gain and loss through windows will be on the order of 4 times what it is through walls, and there is no thermal mass to speak of in windows. Consider overhangs to keep summer sun from streaming through the windows. The payback there starts as soon as you move in, not 10 or 15 years later like with trees.

Absolutely most important! Engage an HVAC contractor who is comfortable with ICF construction and uses a computer program to do the Manual J calculations for heat and cooling load. If an HVAC contractor says, "Oh, so many square feet so that'll be so many tons of AC," walk away from him.

Thanks for the links