I am considering Durisol or Faswall ICFs for an addition to a 1930s house in Houston, TX. The main drivers behind this decision (vs. other EPS ICFs) : doesn't harbor termites, no off-gassing during fires, smaller amount of concrete, insulation of the termal mass on one side only, easier to work with on the inside and outside, etc. But I am not sure whether there's much of a difference between Faswall and Durisol products. Anyone has experience with either or both of those products ? Any reasons to go with one vs. the other ? Is support better for one ? Any help would be much appreciated ! Thanks ! Nicolas.

I have worked with both and would go with Durisol. They have more product variety, have been around longer and have more manufacturing facilities, better tolerances and faster turnaround. The other big difference is that Durisol only uses clean softwood waste material. This is important to some who want to ensure that raw materials do not contain paints, chemicals, etc.

James, thanks for the info. Have you worked with their insulated form ? I am curious how the insulation insert holds up to the presuure of the concrete being poured in the cavity. Does it get compressed very much ? I haven't physically seen the form yet, so I don't know how dense the insert is.

Thanks,
Nicolas.

Nicolas, I worked on a Durisol project in Dallas where they used conventional ICF for the radius portion only and the remainder of the job was Durisol. The inserts do not compress measurably but they also add very little little to the thermal value of the wall. Average R-value yes, but actual r-value no. Thermal transfer just goes around them -- this is why the just approved (in Texas) International Energy and Conservation Code IECC no longer allows foam inserts to count toward R-value for CMU.

Also, thermal mass to the inside does outperform traditional ICF foam on both sides only when mass(mostly concrete) and insulation R-value are the same for both systems. You have far less mass (concrete) and although that might be considered a plus if you not concerned about strength you won't beat the traditional ICF in thermal performance when you utilize far less mass and an actual R-value that is quite a bit lower.

You might also get your job bid both ways since these alternative ICF systems are usually more expensive to install. Turn-key traditional ICF bids for about $10 to $12 per square foot in the Houston area. Regards.

TexasICF,

Thanks for your comments. I had to read that a couple of times to make sure I understood it all. So now, I am a little confused. Durisol has published some numbers about the R-values of its component (nominal, middle, web, total) :
http://www.durisolbuild.com/Webdocs/Durisolthermalperformance.pdf
It looks to me like the webbing material has actually a higher or similar R-value than the middle (concrete + foam insert). Am I not reading this right ? Are you talking about something different ?

R-value is important to me, but I also do like some of the advantages of Durisol and Faswall type ICF over the EPS "sandwich" type ICF.

Thanks,
N.

npvisual, You are reading the document correctly and Texas ICF is correct about CMU, however Durisol and CMU are two very different beasts - Durisol material itself is insulating where as masonry is not. I have used the insulated Durisol blocks and do not find the inserts compressing significantly. I believe they use a roof board product which is fairly dense. I have not used Faswall but am aware of their product. Smaller units (more work!) and less choice as far as I am aware. I have had no problems with Durisol to date. Keep up with your due diligence, it will pay off.

Thanks JakeG. That helps !

How important is the waffle / grid pattern created by both of those blocks from a structural standpoint ? I understand the column design for compressive strength for dead and live loads. So is the grid pattern important for shear loads (wind and seismic loads) ?

Also for those who have built with either Durisol or Faswall, are there any air penetration at the "seams" (i.e. laterally between blocks) ? Is that why an air barrier is recommended (housewrap) ? Or is there a parge coat needed between those "seams" after the concrete is poured ?

Thanks again !

Hi npvisual, The Durisol horizontal core is 12" on centre and I think Faswall is 16" on centre. You want to maximize the horizontal area for shear resistance. I (or I should say my engineer) have not had any issues with shear design using Durisol. The seams in the block are irrelevant and do not need parging; the blocks are porous and therefore imperative that you include a continuous air barrier system. I believe Durisol now offers an off the shelf solution for both above and below grade air barrier and waterproofing system(s). Email their office to confirm. I have always waterproofed below grade and included a dimple sheet of some sort on top (delta MS, platon, etc.). I have also started to provide a damp proof layer between my footing and wall to prevent the ingress of moisture upwards through the wall - cheap insurance. Cheers,

So I have also looked at the Liteblok system offered by Cresco Concrete. I guess it would be in a similar category, but the blocks have fairly different properties. I have seen very few posts on this material, but since it's local to me, I have to consider it as well.

As it relates to the discussion above, the blocks do not create a grid pattern. There's only vertical cores, unless you use their bond beam block to specifically form a horizontal core. I guess that's a design choice at this point, but I was wondering if anyone here has built with those blocks and if they've considered that lack of grid forming property to be an issue.

I guess the subject should now be : Faswall, LiteBlok or Durisol ICFs....

Any recommendations on who to use in the Houston, TX area to pour the foundation, lay the blocks, tie the rebar and pour the concrete (or any of above) whether it's Faswall or Durisol ?

How much does it run, roughly, per sq/ft of wall or 3yd of concrete to erect a building with those forms (i.e. concrete, rebar, labor, but not including the forms) ?

Thanks,
Nicolas

I am building a house in Pa with autoclaved aerated concrete, which you might add to your list as well. Similar in construction technique to Cresco, it uses 3-inch vertical concrete cores every four feet and bond beams on top to tie what it is otherwise solid 8x8x24 concrete blocks (or 10- or 12-inch widths.) AAC is roughly a fifth of the density of regular concrete and is nominal R10 to 15 depending on the width. It has been used in Europe for 70 years. The largest producer, Germany's Hebel, has a plant in Mexico that can't be too far from you. I built mine as semi DIY for about $8/SF. ($3/SF block; $3 labor; $2 steel and mortar.) I have a quote to parge plaster and stucco at $6/SF. The blocks are airtight and paintable as is, although my house wouldn't look very good without more work.
AAC's corners and edges are alarmingly fragile in its block state. But tied together as a wall with few corners and edges, the result is surprisingly strong. I backed my 1 ton van into the garage wall at about 5 mph. The only damage was a dent.
I'd be inclined to find an experienced contractor first and go with the system he uses. Manufacturers want you to believe that stacking-block systems are foolproof but they are not. CMU contractors can probably build with them, but masons are not known for their adventurous nature. I found a gem who moonlighted my house.
If you want these blocks for thermal mass, it does less well in hot and humid climates like Houston than it does in hot and dry climates. I'd be looking at conventional ICF as well.

Typical installation with Durisol is 13 - 17 SF per manhour. Depending on location and design of the house, this can translate to $3.00 - $4.00 per SF for the labour.
How many blocks? How many floors? How many windows? All 90 degree corners?
This will all have an affect.

Well, I am still undecided at this point. I have gone back and forth between the 2 products. Both seem to be very good products and support for each has been remarkable so far (pre-sales). Maybe I'll use my lucky coin...

I'll post some more information when I have made a decision and once I have some quotes for installation.

James : right now it looks like we should be getting about 1,500 blocks for 2 1/2 floors with about 350sq ft of openings. We have mostly 90deg corners, except for one area of the house (about 25deg) extending all the way to the 2 1/2 floor. I did get a quote from both companies.

JakeG : what kind of product do you use between the footing and the wall forms ?

Toddm : thanks. I looked at AAC originally, but decided against them because of the area (hot and humid). But the cost / sqft that you mention for the blocks is very good. All the products I mentioned above are around $8 / sqft for the blocks only.

Thanks !

I use a couple different damp proofing products. henry.com damp proofing 788, 5 gal pail and a few others (WR meadows has some stuff too, can't recall name) good luck.

We install Durisol and other ICF products both residentially and commercially. When completed all perform well. Durisol is expensive to buy and ship to Texas, plus more expensive to install than most ICF's. There are many great ICF products, including NUDURA, Logix, ARXX, Amvic plus several more if you are looking to save money and still have great results.

Posted By npvisual on 24 May 2011 11:17 PM
...All the products I mentioned above are around $8 / sqft for the blocks only.

That is about 3 times more than I paid for EPS foam type ICFs for my home currently under construction by me.

That would imply that they either perform 2 - 3 times better or install 2 - 3 times faster. Which do you think it is?

Thanks all for the information. This is drifting to a debate between EPS / XPS foam ICFs and mineralized wood cement blocks -- which is a great discussion, but not really the topic of my question. For this particular project EPS/XPS foam ICFs were not selected for reasons I mentioned in the first post.

I understand the cost advantages of EPS / XPS foam ICFs and the most recent posts reinforce (pun intended) that notion. But at this point my interest is really about the comparison between Durisol and Faswall -- not other types of ICFs (though I admit I opened the door with my Liteblok question, but I feel it relates more to AAC and mineralized wood cement blocks than EPS / XPS foam ICFs.

I guess I'll have plenty of information for my next project using EPS / XPS foam ICFs !

N.

Send an email to jacksongrandecom.net and I'll send you the contact info for my installer Amin Abdelkader. He's in San Antonio but Houston's no big deal for him. He built my Logix house in Austin last year. I don't know if he's done Durisol or Faswall but I know he did some Amazon projects before they went under. He has a fair amount of multi-story experience too.

put an ampersand in between jackson and grandecom.

Dunno if you have found the Anderson/Sargent zero energy house in Dallas, built with R14 Durisol. Someone there should be a font of wisdom on building with Durisol in Texas. To toss some other names in the mix: Rastra and Apex are closer to you than Durisol. Shipping hurts.

Well, I'm gonna try and put 1 more in the mix for you!  Look up www.ApexBlock.com , has all the attributes of the other 2 you are reviewing except its polystyrene and concrete mix vs wood mix.  There is a distriutor in San Antonio and there are subcontractors in Houston available to you.  Very good customer support and the distributor is owned by an Engineering company to help with any structural questions.  Give a call to Forever Green Concrete Forms for more info.  210-862-0644

toodm : I sent an email to the company several weeks ago but I have not received any response.

balamene : thanks for the pointer to the web site. I'll take a look at the blocks and the company in San Antonio.

N.

We distribute APEX Block tm ICF. If anyone would like more detailed information on the benefits of using APEX Block tm let Forever Green Concrete Forms know