Anyone know approximately what the upcharge is on Logix XRV blocks vs. the standard Logix block? I'm thinking of using standard 2.75" inside and 5" outside, but am wondering how that will affect material cost. I've asked one supplier, but he's been a bit, um, slow in getting back to me. Any insight appreciated.

I am also interested in knowing the answer to this. Free bump for you Earl.

Where are you located?

I'm in central Kentucky, about an hour from Louisville.

I have just put in a request for an 8" Platinum XRV outisde, with standard inside; for a potential Passive Haus client. My supplier is quite good in promplty returning calls, and I will let you know what I find out. The thing is that Logix (at least the Coburg plant) doesn't have set pricing ont it, so every job needs to be priced individually.

I'd suggest calling Logix directly and asking for another distributor. NUDURA also has a thicker-wall option. Where are geographically? Felix

Could you please provide additional information on Nudura's thicker form?

Thanks,
Bruce

Ive only recently been using ICFs. Im a certified installer of Logix and asked my supplier for a full price list.. maybe Logix cost differs from region to region (im in Canada), but I was shocked to find a thicker outside wall would add up to $15.00 more than a standard block!! Ridiculous Price!! how can they justify the extra cost for just extra thickness foam, and you still have to assemble the block yourself! It blows the principals of energy saving out of the water, few clients are going to go for passive building with those prices. I will be contacting the manufacturer directly to discuss this..

Found this on the facebook page of an architect named Edward Wright. Don't know anything else about him, other than that he is a LEED AP. But he says:

"The basic Logix Forms are R-23.5 per form (not including concrete) $20.92 per form or $3.92/sf of wall area
The Logix Platinum Series forms are R-27 (not including concrete)and have a 7.6% increase cost per form of $1.60 ea. or $4.22/sf of wall area
The Logix White XRV with 4" of Foam are R-33 (not including concrete) have a 75.5% increased cost per form of $14.20 ea or $6.88/sf of wall area! An unrealistic per unit cost increase for an additional R-10 (that's very expensive foam)."

That backs up what Caoimhin said, and tells me that I need to seriously reevaluate using XRV. I could drop back to the Platinum, which seems like a good deal for more R, but I was really hoping to go asymmetrical, to get a bigger bang from all that concrete. Maybe I can compensate with more internal mass, like concrete on the ground floor, masonry chimney, etc.
I've also been playing with the idea of stripping away the interior foam from a few key areas, and finishing with cement board, to increase the thermal give and take between the ICF and the interior, perhaps in the areas with the most solar gain. I'd be losing R by doing that, but gaining mass. Worth it or no? Hard to tell without specific modeling.

Don't strip that foam off. It will do a good job right where it is.

On a long term basis, that concrete in the ICF will warm up to a certain point and help moderate things that way. You don't need to be heating and cooling it directly on a short term basis.

If you have so much direct insolation coming in that two thicknesses of GWB or a floor slab can't handle it, you might consider a slate wall or 4" of thin ledge stone or something, but don't throw away your exterior wall insulation that's already there.

I fully agree with ICFHybrid. I would like to add that a floor slab could be thickened if necessary. Capatalizing on passive solar is best done with surfaces the sun strikes and floor slabs usually fit that bill much better than walls.
The thermal mass effect from an exposed concrete wall will moderate, but the storage and release of solar energy comes from the floor slab.
Your heating system will typically allow a 1 1/2 degree fluctuation in temperature before it intervenes. That is such a small amount, that it makes the release of heat from an exposed wall or slab negligible, unless that wall or slab has been heated well over the ambient temperature by direct contact with the sunlight.
Jake Vierzen
R-Value Concrete Structures
616.299.3654

I meant to also include that I did receive my quote from Logix on the XRV panels. The system I quoted was 8" Platinum panel on one side with a standard Platinum panel on the other. $7.15/sq.ft. plus shipping, assembly, and making my own corners! This is r-53, but I can purchase standard Platinum block, and 4" of XPS (bringing it to r-47) for less than $5.00/sq.ft.! It wouldn't be too much trouble to add that XPS on as we are building the ICF walls.
Jake Vierzen
R-Value Concrete Structures
616.299.3654