Folks,

I am looking to build a home on some land in north Texas.  I have not figured out exactly where, ie... Prosper, Lucas, Celina or Van Alstyne.  I know that I want an ICF home and do not want to use a manufacturer that uses foam insulation.  Has anyone built a home using the Durisol blocks?  I like the feel (went to a custom home builder that uses them) and mostly natural products.  I want to hear from people who have actually used them and get their thoughts.  I live in a stick built home now and it is very energy efficient BUT, you can hear literally EVERYTHING that is outside (thunder, other kids, car, etc...).  I am looking to build a home that "heals" and less termite friendly.  I appreciate your thoughts.  Thanks in advance. 

Also, I have look at various other websites and read up on ICF's in general.  I know that I want an ICF for my next home. 

Tony

I guess no one has used them before.

They are not common place when compared to ICF's like Nudura that use EPS insulation with a 6" concrete core.

I believe that Durisol blocks are inferior when compared to ICFs like Nudura. They (Durisol) add very little little to the thermal mass value of the wall. The IECC no longer allows foam inserts to count toward R-value for CMU designs.

Nudura is a monolithic concrete mass wall vs. Durisol which is not and more of a pseudo-hybrid CMU system.

I believe Durisol is BETTER than a wood frame wall system.

Hi:

Yes I have used Durisol before many times and can't emphasis enough how much better (I think) it is over styrofoam or stick frame. Yes, they aren't common like the polystyrene units, but they certainly perform extremely well. Having built and lived in both styrofoam and Durisol, there is no question in mind my mind the benefits of Durisol. In terms of energy efficiency they offer up to R-28 steady-state R-values. This is without taking thermal mass into account. The concept of thermal mass definitely works, but it is not a given and depends on your actual design (building orientation, south facing window area, etc) and location (diurnal temperature cycle). I can't say for sure about North Texas, but you should have an energy model done for your home to determine the optimum insulation level based on these factors. You will be surprised as to how little insulation is required (if continuous) in order to maximize thermal efficiencies. For example, I worked on a project in Florida (different obviously) but the energy model showed that the benefit from going from an R-14 wall to and R-22 or R-28 did not in fact change the energy model appreciably. This is because of 2 reasons. 1. Once you reach that maximized/optimized level, the performance of other fenestrations take over. There is no point in having super insulated walls and simple double-pane windows. So the model showed that after R-14, it is more important to increase the performance of windows/doors/roof, etc. Also, the second reason was that even with premium windows/doors, etc, the increase in energy efficiency for higher R-value started to get smaller and smaller. You were essentially getting to the point of diminishing returns.

Now I'm not saying this will be the case for you. I'm just saying that you need to take a holistic approach and look at the walls, doors, windows, roof all together to make sure you are spending your money in the right places and in the right priority.

I won't comment on the previous post, but I'm sure you can tell that I don't necessarily agree with the implied negative assessment of Durisol. I know that a lot of people here have different opinions, biases and agendas.

When it comes to the other factors of both construction and performance, there are a number of advantages as I see them:

1. Durisol is impact proof and won't dent
2. You can screw into it at any point. You aren't limited to the plastic webs of the styrofoam blocks for attaching.
3. It is a hygroscopic material and regulates humidity. It is a more "natural" feeling environment. What I mean is that you can tell the difference in terms of ambient humidity and comfort.

In the end, if you are interested you should speak to people that actually have built or lived in a Durisol home. I'm sure if you call/email them, they will be able to provide references that you might be able to visit. Talk to the custom builder that builds with it and see if they can provide names/addresses for their previous clients..

Hope this helps.

Lbear,

Thanks for the reply.  The reason I would go with Durisol is because it is a more natural product than a block built with EPS (even though it may be recycled).  I am attempting to build a "home that heals".  Also, since I live in Texas, termites are a BIG deal.  Termites do not like nor tunnel through Durisol but will tunnel thru EPS with no problem.  Also, normally with EPS they need to be sprayed with a fire retardent and/or borate solution to keep the termites at bay.  I understand that some people love the product.  I am not saying that Nudura or Foxblocks, etc... are inferior products, just not what I am looking for in my home project.  Thanks again.

James,

Thanks for replying.  I have seen the videos of simulated tornado speeds with flying debris.  **browser won't allow me to paste for some strange reason**  Youtube them.  It is pretty awesome how ICF stands up to other forms of building.  This home would be built on a nice tract of land so a tornado is a distinct possibility.  I understand that the Durisol blocks are usually more expensive then the EPS but I believe they are worth it.  I may have to contact the builder (Anderson Sargent) and see if I can speak with a few of their past clients.  That should make my decision a little easier.   Much appreciated for the feedback. 

Hey,

I am currently in the process of having a home built using Durisol. Since they are only up to the second floor at this point, I can't comment on the performance or living in the house, but I can say:

- The folks at Durisol are great to work with and I found them very helpful throughout the whole process.

- Durisol blocks are much heavier than regular ICF, and don't go up as quickly. Once they get in the groove, though, they go up fast enough.

- The block widths tend to be as much as 1/4" different, so the interior/exterior surface of the walls can have little ledges where the blocks don't quite match up.

- If you can plan your window and door openings such that cutting blocks is minimized, it makes the process go much quicker. If you are paying someone by the hour to put these up, that can make a big difference.

- Involve your electrician before the first pour - you will need to make sure that there is a clear plan for how the exterior wall electrical wiring/outlets will be done. Make sure that your local building inspectors are comfortable with this.

- The blocks are strong and sturdy - no worries about dinging/denting them during the construction process, unlike foam blocks.

Also - you mentioned you were concerned about termites. Do be aware that the Durisol blocks are a bunch of wood (kindof) chips pressed together, and there could be channels that termites could crawl through to reach the interior of your house and any wood attached to the blocks, even though they have no interest in the blocks themselves. Whatever you do for air sealing will probably keep the termites out as well, though, I would think.

Good luck with your build!

Hi Pascalli2, Could you provide an update to your Durisol build? Has the home been finished or are you still working on it? I am leaning towards Durisol on a build I plan in a few years in NC. Looking for any info from those using them. Thanks.

http://www.greenbuildingadvisor.com/blogs/dept/qa-spotlight/does-autoclaved-aerated-concrete-make-sense

we did on in the thurmont Md., it is extemely tempermental and each block needs to be exact-this is a "no amateur/diy project" plus the lintels had to be cast-in-place solid concrete, lots of thermal bridging, it would be great in warmer climates not sure if its the ticket for around here?
read the llink above.

Hey there,

The house is up, roof is on, and we are doing drywall/plastering now. Now, I'm not physically doing the work myself, but I would say that conventional ICFs would be easier to stack, and make for a smoother, straighter, more even surfaced wall. Having said that, the siding went on ok on the outside using furring strips, and the plasterers were able to even out the ledges, etc, on the inside with their brown coat. Looking back, I would still have gone with Durisol, but that is because of my personal priorities - air quality, thermal mass, and humidity management were very important to me, and I didn't feel that conventional ICF or other construction methods out there lined up with my values as well as Durisol. You need to look at your goals and determine what best suits your personal requirements.

One thing about it is the costs add up. The materials cost was the least of my concerns, actually - there ended up being additional costs associated with it that I hadn't foreseen. For example, where I'm building, they required an engineer to stamp the plans. That means that every aspect of the design needs to be signed off on and quality controlled by the engineer throughout the process. Engineers are really expensive. They charge even just for a 15 minute phone call, and construction crews are not always happy having an engineer double-checking their work and adding requirements that aren't usually there. In the end, you have a guaranteed structure, but, at least in my case, it has cost several thousand extra dollars. Then there are the extra costs of things like plastering the walls - you could attach drywall and paint it, but to really maximize the benefits of Durisol, it should be plastered - that's not cheap, especially if you want natural plaster (a lot of the cement or synthetic plasters are relatively impermeable and block some of the benefits of Durisol that I was interested in). Then there are extra costs of paying various trades that aren't familiar with the material. You have to pick up the cost of their learning curve and mistakes, basically. If you are lucky enough to live somewhere with a crew or two that have Durisol (or even extensive ICF) experience, this shouldn't be so bad.

There were also some challenges with the city getting vapor barrier approval, etc - I needed a building envelope engineer letter to get them to sign off on not having a vapor barrier on the inside (except for the ceiling).

We didn't have the trouble with lintels that billnaegeli mentions, though - insulation was able to remain in place there. The only place where I am bothered by the thermal bridging is where the porch roofs attach to the wall - our engineers required that the ledger that the roof trusses connect to be attached directly to the concrete, which meant pulling out the insulation and cutting out the Durisol block all the way along. The best solution I could come up with for this was to insulate the ledger on the outside so that it won't bridge as much.

All-in, I don't regret going with Durisol. I love the thickness of the walls, and so far the building seems to hold its temperature really well (no HVAC or anything set up yet), but it is not live-in ready, so I can't issue a verdict on performance yet. I am content knowing that they are pretty much immune to moisture damage, resistant to fire, and sturdy as can be. Inside is quite a bit quieter than outside now, as well.

so you had to fur out all the exterior walls? and you had to plaster the interior walls? wow that is a lot of extra work! but you are almost done! enjoy.

One of the problems with Durisol is that nobody has done hot box testing of it. Martin Holladay talks about a true R-Value of R-3 in areas of the block.
Here is Martin Holladay from GBA explaining it:

Bill - It was a lot of extra stuff to be done. To be fair, though, many jurisdictions already require a rainscreen by code, so if I had been building there, I would have had to strap the exterior walls anyway.

Lbear - Martin makes some good points about thermal bridging, but it is a mistake to take that to mean that there is actually an area of the wall where you only have R-3 all the way from the exterior to the interior. I'm comfortable saying that will never happen with Durisol.

Posted By Pascalli2 on 17 May 2016 01:09 AM
 

Lbear - Martin makes some good points about thermal bridging, but it is a mistake to take that to mean that there is actually an area of the wall where you only have R-3 all the way from the exterior to the interior. I'm comfortable saying that will never happen with Durisol.

Martin is a building science expert. There are no feelings or bias in science. The scientific facts speak for themselves.

With Durisol there is 1.75 inch of material (wood chips plus additives) between the concrete and the exterior. That material area has an R-value of about R-3. There is no denying that scientific fact.

Durisol needs to do a Hot Box test using ORNL

I'm not questioning Martin's credentials - I do think his statements are not based on detailed analysis and modeling, though. They were just a response to a thread with his general thoughts and considerations - but either way, he is not saying that any section of the wall is R-3. He is saying that there is R-3 between the concrete and the exterior (although he has it backwards - there is actually R-3 between the concrete and the interior). On the other side of the concrete, there is 5.5" of rock wool insulation, and another 1.75" of Durisol. Even if you discount the value of the inserts (which is silly), the minimum ANY section of wall has is R-6. Realistically, you'll get better than that pretty much everywhere.

For a straight, normal section of wall, based on the most pessimistic view of thermal bridging - where the Durisol webs connect the blocks - heat or cold from outside has to pass through the following shortest path to get to the interior: 7.25" of Durisol material (based on the depth of the Durisol plus insulation inserts that are being bypassed), 5" of concrete, another 1.75" of Durisol material. That makes a total of 9" of Durisol material to be passed through, based on thermal transfer through the Durisol webs that bypass the insulation. If we give the concrete an R value of 0, which it is pretty close to, we still have around R-15 between the exterior and the interior based only on the Durisol. I would not consider an R-15 path to be a significant thermal bridge. This also only applies where the webbing connects both sides of the block - using a more generous method of calculating R Value there, I have seen the argument made that it is actually R-24, based on 14" of Durisol. The truth is probably somewhere in the middle once you average it out, but combined with about R-30 through the center of the block, you get pretty good performance all around. The manufacturer calculates it to be an R-28 whole-wall value.

The area where you could potentially face significant bridging are around openings and roof connections. There is definitely some potential for bridging there, depending how they are detailed and what the engineering requirements are on your specific build. I think in most cases there is going to be a need for some extra insulation or special care around openings and where the roofs connect, etc. I can't make any blanket statements about those though, because they are design details that are specific to each project.

It would be interesting to see how Durisol performs in a Hot Box test - it doesn't seem like it would be that difficult to arrange and I'm not sure why it hasn't been done.

Posted By Pascalli2 on 17 May 2016 04:12 AM

The manufacturer calculates it to be an R-28 whole-wall value.

It would be interesting to see how Durisol performs in a Hot Box test - it doesn't seem like it would be that difficult to arrange and I'm not sure why it hasn't been done.

Any thermal bridging significantly drops any R-Value in that area.

Manufacturers can claim what they want but the proof is in 3rd party unbiased tests. I have a really hard time believing it is R-28 "whole-wall" value. It would require a Hot Box test. The reasons WHY manufacturers don't Hot Box test is usually because:

A - They know the test results will not work in their favor, so why do it and risk it?
B - They don't want to spend the money for the test (it's expensive to do a ORNL test)

Thanks Guys for the good discussion. They build quite a few of these up in Canada so I suppose they perform well in that climate. I am in NC so not nearly as chilly so should be good to go. I really want the breathable wall system. A few questions for Pascalli2

Did you end up doing a lime plaster on the inside? Anyone know if there is a breathable sheetrock out there? May be tough to find ones that do that type of work.
Did you run conduit on the inside of the block for electrical? Wondering if that would be wisest instead of cutting chases.
What type of electrical boxes did you use? Durisol thickness is less than foam ICF so worried about box depth.

Hi - sorry, I have been away for a bit. I ended up going with American Clay plaster on the interior walls. It is actually a bit more permeable than lime, and not as expensive (but still very costly). The way our guys did it is a brown coat of their custom clay plaster blend (not American Clay) to even the ledges and fill the gaps, etc, and then a top coat of American Clay.

We put the conduit inside the Durisol before the pour, but it took some coordination with the electrician. I'm actually not sure what boxes they used, but the city wanted a particular kind because they would be in contact with concrete. If you put them in before the pour, the depth of the boxes doesn't matter. There are a couple of places where I had to cut out the Durisol after the pour to put in network jacks, though, and in those places the Durisol was plenty deep.

Hope that helps.

Sider-Crete in Hawkinsville Ga has breathable plaster formulated for AAC. Dunno if it could be used on composite icf. Its origin is in Europe and its products for AAC have been used there for decades. It was remarkably inexpensive. Even with shipping from Ga to Pa, plastering cost me less than drywall. Please note that drywall on interior walls will not look like plastered composite ICF walls unless you skim coat them with plaster as well.

You perhaps know that there are many manufacturers of composite icf besides durisol, including a couple in Texas. Prohibitive shipping costs are a drawback for composite walls. Rastra is the oldest of them, mixing cement with recycled eps.

Finally, do not be put off by engineers. Any system that's not stud wall or standard masonry requires an engineers stamp, including foam icf. Stamping the blueprints was the end of my engineer's involvement. No onsite inspections. No followup. I'd say that's more common than Pascalli2's experience.

Good luck.

Pascalli2, I hope all is well with your Durisol home. Can you give us a update on how things are with it? ie... size in sf stories average utility bills, etc..... Thanks.