In answer to the R value in your estimate of only 15 +/- is not what HercuWall is claiming. It states it's R value at 30. I would like to see a third party, which I do think has already been done, give a report on the R value. I believe I read on their site that the U.S.GB Councel gave them a Platnum rating for their wall system. So I am skeptical of your R rating of only 15 as traditional construction with wood is only 14. Patrick, Arizona Performance Homes

With steel furring thermally bridging the foam 24" o.c. that's a HUGE thermal bridge, and no matter what they do for honeycombing the concrete, it doesn't mitigate that bridge very much. Even if they have 4" of EPS on each side of the concrete (and it looks more like 2.5 - 3" in the pictures), it won't be anything like R30.

If it's 3" (~R25 nominal), after thermal bridging it will come in well under R20.

If it's really 2.5" (R21 nominal) the R15 estimate is the right ballpark, but may even be on the high-side.

The only claims to R30 I could find in their lit is on p.3 of their brochure:

http://www.hercuwall.com/docs/HercuWall.pdf

"What's more, 2x4" wood only provides a drafty R13 insulation envelope rather than HercuWall's R30 with no drafts".

That might actually be taking them over the line from the FTC's misrepresentation point of view, since they're assigning it an R value without an ASTM C 518 test, but maybe they're hoping because they're selling a wall system, and not insulation maybe it'll fly?

That quote also mis-state the performance of the 2x4 wall, since at typical framing fractions and siding options R13 stick-built comes in at ~R10 whole-wall, not R13. That implies either that they just don't understand it, or that they're hoping the reader's comprehension is similarly clueless.

A 2x4 stick built is a fairly low-performance wall (even when done air-tight), but still code-legal in much of US climate zones 1-3 but rarely passes legal-muster in other US locations. An R15 mass-wall would be a significant uptick from there, but it's something of a straw-man argument.

ICFs that don't have metal furring short-circuiting foam every 24" heat-sinking in the concrete will outperform it with good margin. Just as with stick built "It's the thermal bridging stupid!"- putting the foam on the exterior of the thermally conductive elements (metal furring or studs) rather than between them is essential to getting the true thermal performance out of the foam.

It's akin to making an assembly with air tight materials but with full length slots every 24", then wondering why it isn't stopping the wind any better than it does. No matter how tight you make the middle sections, it does nothing to slow down the air flow in the slots.

It's possible to build a high-performance wall using that system, but it would involve adding a layer of exterior foam held in place with flat furring through-screwed to the metal furring 24" o.c. for minimal thermal bridging (just as with stick-built foam-over designs.)

Thank you for the education. I presume you do this for a living. Stupid implies not capable of learning. Ignorant just means someone is not informed. I like to assume people are ignorant and not stupid. Once again, thank you for the education.

Posted By Dana1 on 07 Aug 2013 04:16 PM

If it's 3" (~R25 nominal), after thermal bridging it will come in well under R20.

If it's really 2.5" (R21 nominal) the R15 estimate is the right ballpark, but may even be on the high-side.

ICFs that don't have metal furring short-circuiting foam every 24" heat-sinking in the concrete will outperform it with good margin. Just as with stick built "It's the thermal bridging stupid!"- putting the foam on the exterior of the thermally conductive elements (metal furring or studs) rather than between them is essential to getting the true thermal performance out of the foam.

It's akin to making an assembly with air tight materials but with full length slots every 24", then wondering why it isn't stopping the wind any better than it does. No matter how tight you make the middle sections, it does nothing to slow down the air flow in the slots.

Very well put. The HercuWall system does not perform energy wise as well as typical ICF does (2.5" x 2.5" EPS). The HercuWall claim of R30 is in no way the true wall rating with the thermal bridging every 24" oc.

I believe HercuWall wanting to get some business struck a sweet deal with Meritain to get the system introduced into some of its new housing. This is a trial run and the houses are limited.

I am not a fan of honeycomb concrete walls and of course I believe typical ICF (2.5" x 2.5"EPS ) performs better than a HercuWall system, both in R-Value and strength. I will take a monolithic 6" concrete wall over a honeycomb wall. Especially in a Phoenix based climate where mass is beneficial more so than in a Zone 6 climate. There is more concrete mass in a 6" ICF wall than a honeycomb HercuWall.

I do applaud Meritain for going the concrete route but they should have chosen a standard ICF block and they would have come out better in the long run. As mentioned before, I really believe the reason for their choice is that HercuWall struck a sweet deal to get their product into some spec housing deals. The limited amount of concrete needed in a HercuWall honeycomb wall vs. a 6" ICF wall was probably another cost saving measure.

Posted By AZPERFHOMES on 07 Aug 2013 04:54 PM
Thank you for the education. I presume you do this for a living. Stupid implies not capable of learning. Ignorant just means someone is not informed. I like to assume people are ignorant and not stupid. Once again, thank you for the education.

I didn't mean to imply that anyone here was actually stupid- it was just borrowing a line from Bill Clinton's presidential campaign strategists:

"It's the economy, stupid!"

...as a reminder to keep the critical aspects in focus.  In high-R assmblies it doesn't take much in the way thermally bridging elements to bring the actual performance to it's knees.  The extremely high thermal conductivity of steel & moderately high thermal conductivity of concrete relative to EPS defeats the average performance by quite a bit: 

Steel is 50-100x as thermally conductive as concrete.

Concrete is about 50x more thermally conductive than EPS.

Steel is 2500-5000x as thermally conductive as EPS.

So in rough terms a square inch of steel cross-section conducts as much heat as ~25 square feet of EPS (give or take, depending on the type of steel and it's platings.)

But in this case it's further compicated by the three-dimensional aspects- the steel furring is folded over the EPS on the exterior and the interior, providing even greater conductivity between the steel and outdoor air, and between the steel and the concrete, amplifying the effect beyond what the mere cross section of the steel between the EPS edges would be. A simple 2-D model doesn't do it justice- even a better-class finite element 2-D tool such a THERM would have significant errors. It's probably simpler to just run an ASTM C518 test on a representative wall section using a very large test plate.

And if that actually delivered anything close to R30 performance I'd probably faint!

I'm going to revitalize this old thread

and I'll post pics too as we go

We are installing 24,000 sq.ft. of Hercuwall on a mid-rise condo in Toronto - this is a first for Hercuwall for a building of this size, 4 floors total of Hercuwall, it is the first Hercuwall project in Canada

Basement level is 5' below grade, this is a first for Hercuwall - It's an Arizona company - no basements

First 3 floors are the series 9", 4th floor is series 8"

They do promote R30, but I will say that is based on Arizona, currently we are getting it done with a larger delta, -30c to + 30c to see what it comes out to

For those of you who doubt the energy efficiency of the system due to thermo bridging, you maybe right, I can't argue as I am not a heat loss designer, but I will say that cost comparison to conventional ICF this project is over $ 100,000.00 cheaper just in the wall cost alone, add in the fact the walls with less concrete are lighter so that meant savings on the suspended slab as the integral beams could be smaller and the savings goes up even more.

Looks like Hobbs. Shipping the system from Arizona must be expensive.

I've not touched or seen Hobbs.

Typical panel is 4' wide, height is whatever I need. Each job is project specific, unlike ICF where we can just order block and make anything on site, your plans need to be submitted a min. of 1 month in advance so as they can model your project, engineer it, product it, get it to site.

Since this is the first on many levels, shipping from Arizona was included in the negotiated price from them to me. They are a young company and expanding, sooner rather then later there will be a manufacturing facility nearer to me, as I have sold more of these type projects, they need to get the material more efficiently.

First day was unload the truck, layout, see what it was all about

2nd day we had to prep the panels for our project, we needed to create pockets for a brick ledge, Hercuwall does not currently have a brick ledge form as I do not think brick is that common in Arizona, nor would be suspended brick as we do basements here, so brick starts above grade.

3rd day the guys put their heads down and installed 74 out of 88 panels

Monday the next load arrives. I expect we will have it unloaded and installed by end of day Tuesday. I could pour Tuesday or Wednesday, but I want to hang the 1000' of rim board with anchor bolts and all the hangers for joists installed prior to pour, so probably Friday or Monday.


Pro's and Con's so far

It is faster then ICF on the build side, they are big panels, there is no rebar since the sheerstrip replaces it

Since it is factory made for your job, changes are not easy, so if someone wants to move a window in the field, make the wall slightly larger, it's not happening very easily, which from a contractors point of view is a Pro, a Con for others.

I've done a bunch of panel systems with various blocks and form and it just makes more sense that dealing with individual forms. Any time you can save time on the job is money in your pocket.

Posted By Chris Johnson on 16 Sep 2015 10:55 PM
I'm going to revitalize this old thread

and I'll post pics too as we go

We are installing 24,000 sq.ft. of Hercuwall on a mid-rise condo in Toronto - this is a first for Hercuwall for a building of this size, 4 floors total of Hercuwall, it is the first Hercuwall project in Canada

Basement level is 5' below grade, this is a first for Hercuwall - It's an Arizona company - no basements

First 3 floors are the series 9", 4th floor is series 8"

They do promote R30, but I will say that is based on Arizona, currently we are getting it done with a larger delta, -30c to + 30c to see what it comes out to

For those of you who doubt the energy efficiency of the system due to thermo bridging, you maybe right, I can't argue as I am not a heat loss designer, but I will say that cost comparison to conventional ICF this project is over $ 100,000.00 cheaper just in the wall cost alone, add in the fact the walls with less concrete are lighter so that meant savings on the suspended slab as the integral beams could be smaller and the savings goes up even more.

'bout those pictures? ;-)

https://plus.google.com/photos/102217322491700176504/albums/6160063539639679873 I'll get on to my guy to update it regularly

We build our walls in 20' sections, it's easy for two men to carry and saves a lot of time on the job. The days when it rains is a great time to build the wall sections indoors.

One thing I am really happy with this Hercuwall system is simplicity, lets be blunt, employees are not the easiest at times to work with or the most intelligible creatures. Since the only rebar is on the top, you really don't need to train people since there is so little to do.

The plan they send is really simple, every panel is labelled, so the label is to the inside and at the top, can't really mess it up before someone notices.

Tomorrow is pour day! 40mpa (6000 psi) 21" spread (pretty much water) SCC mix