Looking for opinions on these systems. I'm looking to build in the Phoenix area and want a higher true R-value wall to control summer time heat where thermal mass isn't effective (can't cool off during the night and gets heat soaked). Hobbs and Mikey block replace some of the concrete for more foam, saving concrete costs and increasing insulation. Hobbs claims significant labor savings in their vertical system and that appears to be true from what I've read/ watch. Quad-Lock has great exterior insulation options with more traditional blocks. Their R-28 and R-38 blocks are very appealing. I like the thought the concrete grid instead of the solid concrete wall for savings but it seems (in my mind) that quad-lock trumps the others in insulating performance. Thanks!!

Posted By gracilism on 17 Apr 2016 04:02 PM
Looking for opinions on these systems. I'm looking to build in the Phoenix area and want a higher true R-value wall to control summer time heat where thermal mass isn't effective (can't cool off during the night and gets heat soaked). Hobbs and Mikey block replace some of the concrete for more foam, saving concrete costs and increasing insulation. Hobbs claims significant labor savings in their vertical system and that appears to be true from what I've read/ watch. Quad-Lock has great exterior insulation options with more traditional blocks. Their R-28 and R-38 blocks are very appealing. I like the thought the concrete grid instead of the solid concrete wall for savings but it seems (in my mind) that quad-lock trumps the others in insulating performance. Thanks!!

Thermal mass is very effective in a Phx climate area and the climate rates as one of the best places to take advantage of how concrete reacts with its thermal mass.

There isn't much money savings in "grid"or waffle systems and a solid concrete wall is much stronger and performs better than a waffle grid system.

Best system for the Phx area would be a solid monolithic concrete wall with 6" of reinforced concrete and using a block like Nudura which folds during shipment for savings and has 2.5" of foam on each side.

Where in Phx are you looking you build?

East Valley on a couple of acres. I contend that thermal mass is not effective during the time of year that efficiency is most important. With months of 100+ highs and 85+ lows the mass becomes heat soak and constantly flows to the interior. I'm not sure how much insulation is needed to stymie the thermodynamics, but thermal mass by itself is less effective than high insulation and air sealing without the diurnal temperature swings. That said, the strength of concrete, its air sealing capabilities, and its sound control are big pluses. "Greg Kallio, a professor of mechanical engineering at California State University in Chico who specializes in heat transfer, recently tested this theory by modeling “the whole gamut” of wall systems, from stick-built to SIPs to insulated concrete, using industry standard energy analysis programs like EnergyPlus, as well as his own custom software. His conclusion? “The effectiveness of thermal mass is very dependent on diurnal temperature variation. You want nighttime temperatures that get at least 10 degrees cooler than the thermostat set point. If you keep the thermostat at 78, outside temperatures need to fall below 70 degrees at night to really take advantage of the thermal mass.” Heating and cooling is easy 7 months of the year when thermal mass would work great. But its when you really need an effective thermal envelope is when it basically acts like a R-2 wall feeding heat to the living space. Thank you for the recommendation. I will research Nudura further.

BuildBlock has a product "Global Block", and while I would not use it in Oklahoma, it is being used in Mexico, for the reasons you state. And do not be afraid of the strength of a grid block. Especially, if you don't have the issues of storm safety we deal with. I would add, I would not use a grid block for basements, but it stands on its own in strength.

I know some local ICF builders use BuildBlock. I do like that they use a higher density foam making the 2.5 inches more effective. Thank you for your recommendation on "Global Block". I will research it further. Thank you for your time.

Lbear, the waffle grid walls perform just as well as the solid core walls in residential buildings. It's about the rebar used in conjunction with concrete that determines a walls strength. If you use the Prescriptive Method to design the rebar layout there is no difference in strength. I would think that a 40% reduction in concrete cost, that in my case cost about $100 a yard is not an insignificant amount of money. The big difference in labor cost as well as the concrete savings would make the Hobbs system my choice, when considering your insulation requirements. The Global Block , I believe is molded in AZ so shipping should be reasonable. It's an interesting product, brings me back to when I started. I'd use it it it was available here in upstate NY.

Waffle grid systems are a bad idea. Do you really want a wall you can shove a rake handle through? Many locales and US Army Corps of Engineers do not permit them to be used. But we are biased. Polycrete Big Block has a 4mm welded steel wire mesh embedded in our EPS panels so they withstand 1,600 lbs/sqft of lateral pressure during the pour. We also use 1.44 lbs/cubic foot of EPS instead of the 1.35lbs that most of the other manufacturers use, so our foam is denser to begin with. XpressWall kits have now changed everything.

Thank you for your perspective Bruce. I'm checking out your product now, does your BigBlock have any restrictions when cutting it down for windows or doors? They seem like a good product for my simple 4 corner house. I am also interested in your extra 2.5" insulation option. That should go a long way for my efficiency goals.

Thanks Smartwall for your perspective. Hobbs is interesting. I don't believe its a true waffle design, just a thickening and thinning of the foam. Its installation is probably the most DYI system out there even though I won't be doing it myself. Its simplicity of installation and concrete savings are pluses. I wish I could achieve a more uniform thickness on the exterior like Quad-Lock, BuildBlock and Polycrete. In my mind, that would have better total wall performance having that consistent thickness of insulation. I'm not sure if that difference would be significant and I haven't even started pricing, so those systems might price themselves out of the running when extra panels (or just thicker in Quad-lock's case) are included.

No restrictions to speak of. As far as cutting goes, our new XpressWall is a complete pre-cut kit. Working from your plans, we make all the cuts in the factory and send you a numbered and labelled kit. All you have to do is assemble it onsite, set door and window bucks, brace, add rebar and pump concrete. There is an electronic brochure on the PolycreteUSA website or you can PM me for details.

No restrictions to speak of. As far as cutting goes, our new XpressWall is a complete pre-cut kit. Working from your plans, we make all the cuts in the factory and send you a numbered and labelled kit. All you have to do is assemble it onsite, set door and window bucks, brace, add rebar and pump concrete. There is an electronic brochure on the PolycreteUSA website or you can PM me for details.

Can't put a rake thru a waffle grid, might be able with a screen grid. Bruce I thought you would know the difference.

Wall Comparison



I personally don't like Waffle or Screen Grid walls. Screen Grid is not allowed on many builds due to its inferior strength compared to solid flat monolithic concrete walls.
If you go concrete might as well do a solid 6" thick wall.

Must be I need a new PM since it's in there with the required rebar schedule Section 4 page I 34 I believe. But Lbear knows better. Let's do a test the better wall is, screen grid or 2x6 with osb ? I'm sure that Build Block doesn't know that it's selling an illegal product. May be a phone call to Build Block tomorrow would be wise. I forgot, better call Mickey Block too, their in the same situation.

Waffle grid, screen grid. Whatever, it's all the same to me.... substandard. Spend the extra 5 bucks and do it right instead of cutting corners to save a nickle.

Speaking of cutting corners, I believe they have preformed corners not straight blocks that have to be cut to form a corner. Saves time.

Haha good one Smartwall. But Polycrete has now made ALL cutting obsolete. Check this out for an eye opener. No other ICF manufacturer does this... http://polycreteusa.net/s/XpressWallv2.pdf

Actually, I received your email about it and I think it's a winner. What is the up charge for the service if you don't mind me asking. It's something that I switched to this year. I now sell all my icf's in ready to install panels. From 8' wide to 20' by whatever height is needed, Like your system it's a big time saver. Since a great deal of my sales are foundations, used in conjunction with my mono pour system it cuts the build time by 75%. The real question if this system is viable will be Mojoe the expert on icf's.

Back to the original post, gracilism, I think you should look at Mickey Block since it's in Az. It's a small co. and could lead you in the right direction. The only question I would have is the type of exterior finish you are considering?

Price varies based on complexity of the job. Never had anyone decline a quote yet, so that implies it makes sense. Send us a set of plans and we'll give you a quote.