Hello, I have read through many forums and seen a lot of comments on this already, but I wanted to solicit a bit of advice regarding Durisol ICFs. Information on the product can be found here: www.durisolbuild.com. The advantages of their product seem to be what I am looking for, but I wanted to see if I could stir up some conflicting opinions. My two main concerns when building are air quality and energy efficiency. We are striving to build a home that is as close to zero VOC/SVOC/ETC as possible. Two things draw me to Durisol over traditional ICF. The first is that they use no foam, and seem to be made out of inert, non-offgassing ingredients. I am concerned about the flame retardants used in ICF foams, as well as potential toxins in the foam itself that are considered to be "within safe levels" and not really commented on, but still present. Secondly, I am intrigued by the idea of "breathing walls" and the benefits to IAQ that can be gleaned from having vapor permeable walls. I realize that some feel this is of negligible importance or irrelevant or harmful, even, but they have done significant research that seems to indicate that this is a good thing and not a bad thing. Finally, I have seen several posters comment that the forms themselves serve as a thermal bridge, as they are relying on the insulating inserts for their R-Value. If somebody could elaborate on this, I would appreciate it, as it seems like the forms have an R-Value of 1.75/inch - this puts them at roughly the same R-Value for the full 12" depth of a wall as the section that has insulation and concrete poured into it. Shouldn't they not act as a thermal bridge in that case? I am especially interested in people's first-hand experience with Durisol (even more so if they have information from post-build). Thanks!

Hi Pascalli,
I have built with Durisol a few times. My clients chose Durisol for some of the reasons you have mentioned, but more so for the recycled aspect of the form and high thermal resistance (the last one used the R28 form, 14" thick!).
The thermal bridge issue is not really an issue. You are correct in that the insulation value really doesn't change when looking through the block at a web or at a location where the Roxul insert is located. I have not done any thermal scans, but I know Durisol's office has a good handful of shots of various projects - ask to see some, they are interesting! I think at the end of the day, the Durisol walls and any other type of ICF walls will show the same quality when scanning with a thermal camera - they work very well.
The VOC/SVOC are a lot more technical than what I've dealt with. Google Oram Miller from " create healthy homes" or Robert Stiller from " breathing easy". These consultants have either tested the material or had 3rd parties test the material for what you have mentioned. I met them both at healthy housing seminars in Ontario. I know Robert has built with Durisol himself. Oram has consulted on some large projects that required his expertise. They will have real 3rd party insight into what you are looking for.
Most people get confused by " breathing walls". The structure needs to be air tight. The fact that the Durisol wall is very vapour permeable makes it a breathing wall. We tried to achieve this a couple of times. You have to be very careful with your finishes and air barrier materials to achieve this. Breathable finishes on the exterior but watertight (i.e., BAKOR has a VP160 house wrap, breathable natural stucco, ventilated siding, etc.) Interior we used lime plaster. Very permeable. The clients are happy. Can they tell the house is vapour permeable? I really don't know, but they say they can " breathe" the difference. I can't disclose my client list but I know years ago Durisol gave me a substantial list of customers who I could contact and ask directly.
Good luck!

Thank Jake,

That is very helpful - I am going to see what I can find out about Oram and Robert. Right now, I am thinking of doing Durisol walls with lime plaster directly on the interior, but am still considering options for the external wall finishes. I think, since I don't have any particular fondness for the aesthetics of stucco, I am best avoiding that cost. I'm thinking something like hardiplank on the outside, with strappings and an air barrier wrap of some sort (will check out BAKOR) - though I haven't looked into the permeability of Hardiplank. I think if I was in Ontario, I would be sold on the idea of Durisol at this point, but shipping costs to British Columbia really smash my budget.

Thanks again for the response!

I like the breathability and the more environmentally friendliness of the product. My concern is the R-value performance as well as cost and availability of them. Are they available in Iowa for instance? And what is a ballpark cost?

Hi agagent3,

I bet you could get them for a lot cheaper shipping in Iowa than where I am building (BC). The blocks themselves come in considerably more than wood framing, but to me, the benefits offset that cost. It's hard to specify on pricing, because it depends on the blocks you specify, how many corners in your design, etc. Add to that the variance in the cost of concrete and rebar in your locality, and there can be quite a difference. I would estimate for all materials (only), you would be looking at $7-10 per square foot of wall space. I, however, am not a representative of Durisol, and would recommend that if you are seriously considering Durisol that you contact them to discuss pricing and get a formal quote. I have found in all my dealings with them that they are very helpful and informative.

The highest insulated block at an actual R-28 value, when combined with the thermal mass benefits should provide plenty of insulation, in my (again, non-expert) opinion. I'm sure there are plenty of people who could chime in on that with facts and figures supporting one thing or the other.