Pacificstart is right about Nudura. It uses a 8' panel and would leave you with more usable plywood that with h clips could be used on a roof. It's also manufactured in Ga and with it's folding system allows for more product being shipped. You've asked some good questions. Good luck on your build.

Posted By smartwall on 06 Apr 2016 03:44 PM
Mojoe, I missing an agenda here. How many icf projects have you been involved with. The product she is considering using is a commercial product. The expose thermal has been dealt with on this site probably since its inception in the early 2000's when it started as icfweb. One consideration to any house build should be what will the market be for a New York loft style interior in eastern NC, Some day the house will be sold and the decisions that you make now will effect its price. I would use Quad Lock unbalanced wall system. Whatever thickness of foam you choose outside with their 2.125 " insulation inside. I don't sell the product but I think it is something that a DIYer could use. It's a knock down so shipping from Georgia shouldn't be too much.

smartwall, No one mentioned you by name so do you have a guilty conscience or are you trying to say that my recognition of the obvious is somehow incorrect? You told her that her desire not to have foam on the inside will reduce the insulation value. Is that the kind of professional advice that has taken you so long to arrive at? Do you really think that had escaped her or doesn't it fit your non-agenda? What about her stated fondness for the look of stained or plastered concrete that you dismiss and insult? Thousands of small holes could be easily covered by a thick base or scratch coat or just stucco. Living in a house that might appeal to someone else someday sounds ridiculous to creative people wanting to live their own dream instead of someone else's. Wall coverings can easily be added at any time by anyone who knows what a tap-con and polyurethane adhesive is. Being an ICF corporate sponsored forum, it's not overly surprising that you have reached the conclusion that foam on the inside is best even though it isolates the thermal mass. Many companies seem to be or have already moved toward providing a one sided option as most people are aware of the benefits of exposed thermal mass. Using the same amount of insulation but putting it all on the outside would be far more energy efficient. Don't kill the messenger….

No guilty conscience here. I'm trying to point out the possible pitfalls to using the one side product. I'm in upstate NY so I have no product to sell someone in NC. Been involved in the icf business since 1989 so I have a pretty good back ground in the business. I think it's the best product to build any structure. Started my business career in the insulation business so naturally I gravitated toward icfs. The product she is thinking of using was created to build stair wells and elevator shafts to go along with icf commercial projects, not residential. The value of a thermal mass wall with diminished exterior insulation is counter to the reason for the mass in the first place. Concrete floors are the better choice inside the insulated shell. Stucco, scratch coat material can all be added to the interior of any icf. So why take the extra step on a concrete wall. I repeat since you are an expert in single side icf's, how many icf projects have you been involved in? I'll listen to any messenger if he has used the product and can inform with actual experience not just reading form web sites.

To smartwalls point the one-sided form system is mostly a commercial product. I was involved in the early Prototypes for the Nudura one-sided system and have been involved in about seven or eight projects that have utilized it mostly for elevators and stairwells. It is a very good system and I do see that the market is recognizing this since there are some facsimiles or similar designs now coming out by other players in the market.

However, it does represent additional labor and I would be slow to recommend it (over conventional ICF) on a residential job for the entire inside of the envelope. That said, my real hesitation is more complex. It is true that the exposed thermal mass to the inside will perform slightly better than a traditional Icf system.
However, for this to be true you have to have the same external insulation as you would for the two-sided system so you'd have 5 1/4 inches of external insulation and you would need to have the same mass of concrete (heat capacity) in order to realize that benefit.

There are a lot of people out there somewhat misusing these lab reports or tests by implying that the mass is exposed so it's going to perform better but again it has to have the same heat capacity (mass) and the same amount of external insulation as the two-sided system to realize this benefit.

I really do like the ability to easily run electrical in the interior foam. Regards

In the interest of avoiding the 973rd incarnation of this argument, perhaps we can just agree that the dynamic benefit of massive structures (DBMS) varies greatly by climate. I will concede that in Nome Alaska, yes, you probably do need an equal amount of insulation on the outside. Elsewhere, on days when the average between nighttime low temperatures and daytime highs is comfortable, then mass buffers that swing and reduces the need for hvac (and/or insulation.) How much depends on how widely daily temperatures swing. Because this happens in 12-hour segments, interior foam likely is a hindrance rather help.

None of this matters much in NC. It's quite possible to have too much mass (assuming no passive solar.) Mass has no benefit once the average daily temp falls below, or climbs above, comfort and stays there. If the house cools or heats for an extended period without hvac, it may take more than a heat pump to make up the btu deficit in a timely manner. I'm thinking a slab on grade is plenty in NC.

Some suggestions:

Tilt-up concrete/foam walls are faster than conventional icf -- to say nothing of plywood framed icf. Look at Thermomass as a cast-in-place system if you can't find a local plant. Also consider poured walls with foam inserts. Certainteed's ThermEZE is an example. It may be difficult to find a contractor if basements are rare in your part of the world.

Unless you are wild about stained concrete, skim coat plaster is faster and not outrageous in price if you avoid companies that price it as restoration work. It's not quite yet a lost art. I found a terrific guy, an artist really, who learned the trade with his dad back in the 60s.

If you can't find a reasonably priced plasterer, consider texture paint. It lays down as a super thick base to which you can apply finishes. Or not.

Look at Legrand wiremold as a painless albeit institutional looking answer for electric. It's an exposed steel raceway for wiring attached to the wall.

AAC surely is a better bet for interior walls than solid concrete by any installation method. Aercon in Fla sells 2' wide 4" thick panels that would go up almost as quickly as stud walls. It can be cut with regular power tools. Consider outdoor (wet use) UF-B wiring as a code approved alternative to conduit. (Check with your building inspector.) Routing a channel between courses and cutting in outlet boxes is relatively fast in AAC (but impossibly dusty; stay away.)

Good luck.

Posted By TexasICF on 07 Apr 2016 03:04 PM

However, it does represent additional labor and I would be slow to recommend it (over conventional ICF) on a residential job for the entire inside of the envelope. That said, my real hesitation is more complex. It is true that the exposed thermal mass to the inside will perform slightly better than a traditional Icf system.
However, for this to be true you have to have the same external insulation as you would for the two-sided system so you'd have 5 1/4 inches of external insulation and you would need to have the same mass of concrete (heat capacity) in order to realize that benefit.

There are a lot of people out there somewhat misusing these lab reports or tests by implying that the mass is exposed so it's going to perform better but again it has to have the same heat capacity (mass) and the same amount of external insulation as the two-sided system to realize this benefit.

I really do like the ability to easily run electrical in the interior foam. Regards

The traditional ICF forms with 2.5" of foam on each side and a concrete core are the easiest to run electrical, plumbing and install finished drywall. The attachment points @ 8" o.c. in the ICF make it easier to install drywall and other attachments (paintings, etc)

Like you & Smartwall mentioned, the raw concrete interior finish is meant for commercial use. Plus one would have to have 5"+ of exterior foam to make up for the R-Value loss.

Since we are here and LBEAR mentioned it - how do you find the plastic webs locations to screw into and attach stuff once the drywall was installed and painted? Using a measuring tape from the end of the wall and count where the webs are at 8" OC is still guess work. If the ICF has been cut and joined then the math of 8" wouldn't work and if you can't start from the end of the wall that won't work either. So how to do it then?

smartwall, Who is suggesting "diminished exterior insulation"? I suggested increased exterior insulation by the addition of the same amount [or more] as would normally be found on the inside. I don't know how many times this subject has been broached but to not recognize the superior energy efficiency of exposed interior thermal mass is more than just short sighted. It's more like burying your head in the sand. I wasn't advocating a specific product just a concept - and unlike you, I didn't ask about your ICF pedigree, either. I'm content to discuss the facts without resorting to a contest about whose hands are bigger. I built my first deliberate passive solar house in 1981 if it matters although we always tried to position even conventionally built homes toward the south for the best exposure. It was a 30 x 40 two story garrison saltbox with an attached 2 car garage with in-law apt. sitting on a thick insulated slab consisting of 53 yards of reinforced concrete and containing hot air ducts and floor registers for circulating air from the cathedral ceiling upstairs and from the wood furnace. There was also a 10 foot wide, 3 foot deep, and 20+ foot tall interior fieldstone chimney to add more interior thermal mass. It stays comfortably warm or cool for about 3 days if the power goes out. It heats easily with a couple armloads of wood on a cloudy or snowy NH day and cools with just a single through the wall a/c in the summer. It has never had a backup heating system and yet is left for a week or more at a time in the winter for trips to Florida without pipes or plants freezing. The beneficial contributions of exposed thermal mass to comfort and energy efficiency should not be overlooked. Water is another excellent medium for thermal mass storage.

I'm considering a method I've never tried before using plywood forms on both sides and removing the interior forms to use again and leaving the exterior in place. Using 2 x 6 strong backs on the outside forms would allow room for spray foam and provide nailing for any exterior sheathing, siding and trim. I know it sounds like heresy to the ICF only crowd but wait - the concrete walls would provide the support for ICF floor forms like lite-deck or quad deck that would provide more interior thermal mass that can contain radiant tubing for heat. Some of those have built in chases for plumbing and wiring, too, and the span capability is impressive. I'm not afraid to share techniques or information and I'm willing to try it on myself first and put my own money where my mouth is. I'm glad people have been so forthcoming with the OP and didn't just give her the standard, "hire someone" response.

Well the blocks should only get cut at one point in any given wall and that point should be near the middle, or along a door or window opening so measuring from your nearest corner should get you to the correct location. You can also use a magnet to help you locate an existing dryall screw...

I was careful with my block layout, so except for one area in the basement (while I was learning) my 8" spacing is intact. I wound up drawing each wall and its block layout to minimize waste, and keep everything in line. Oddly enough, my cheapo stud finder seems to pick up the plastic webs.

Posted By pacificstart on 07 Apr 2016 10:19 PM
...how do you find the plastic webs locations to screw into and attach stuff once the drywall was installed and painted? Using a measuring tape from the end of the wall and count where the webs are at 8" OC is still guess work. If the ICF has been cut and joined then the math of 8" wouldn't work and if you can't start from the end of the wall that won't work either. So how to do it then?

A magnetic stud finder can be used to locate the drywall screws which should be in the webs.  You can then use the screw locations and measure over in 8" increments to locate other webs.

This one uses rare earth magnets and gets good reviews:  http://www.amazon.com/CH-Hanson-030...B000IKK0OI

I have a lot of new ideas (and really helpful advice) to cruise on for a while.  Thank you all for the help over the stumps!  I'm sure I'll be back soon when I get stumped again - and please feel free to toss ideas my way anytime.  Especially the form and function merges - like the wall mount radiators I saw recently that were formed into some beautiful shapes.  Wish I had the thousands for that price tag...

If pex tubing in the slab can provide for a comfortable experience in New England, Im sure it can even more easily handle NC. It's the most appealing heat I have ever experienced as it radiates uniformly from below. Your feet are warmer and your head is cooler which is usually the best. It is also conducive with solar as it requires a lower temperature fluid than baseboard or radiators. It is also completely hidden so no external worries like leaks from damage to baseboard or radiators. Some solar panels are dual purpose PV and hot water. The hot water performance is slightly diminished which probably isn't as much of an issue as it is around here but the water cools the PV panels and makes them more efficient so it might be worth the trade off. You'll have to determine how much hot water you need or can deal with when you don't require heat - maybe a pool or other heat dump in summer?

I don't think anyone would debate that HR heating is by far the most comfortable heating approach.

TF Systems also has an option to eliminate the EPS on the interior wall side (and also has an option to create an air cavity for electrical and plumbing on the interior wall side) and increase the EPS on the exterior wall side. TF Systems uses vertical panels in lieu of blocks. As such, PEX can be easily installed to create HR cooling/heating walls.

There is no reason to speculate on ICF performance these days. The precise effective R-value can be accurately forecast using the software that we developed a couple years ago. Performance varies depending on the actual 24 hour temperature cycle and the actual ICF build up.

Borst ICF Performance Software

Posted By sailawayrb on 10 Apr 2016 10:27 PM

There is no reason to speculate on ICF performance these days. The precise effective R-value can be accurately forecast using the software that we developed a couple years ago. Performance varies depending on the actual 24 hour temperature cycle and the actual ICF build up.

Borst ICF Performance Software

I remember reading a few years ago about how you calculated that the ICF performed as high as R-66 and the overall R-Value for the whole year averaged out to around R-43. Is my memory correct?

Also, per your calculations, isn't the best scenario with the EPS on BOTH SIDES with the concrete sandwiched in the middle?

OK, sure, whatever you say.

sailawayrb, How does the radiant cooling work? Are you talking refrigerant or just water?

You use a refrigeration plant or chiller to cool the water that you would normally heat and circulate thru the pex tubing. You must insure the radiating surface such as the floor or wall does not drop too close to or below the dew point and start to condense moisture out of the air... Because of this limitation, this form of cooling does nothing to lower the humidity level inside the envelope...

Mojoe, HR cooling can be accomplished by circulating chilled water. Ronmar’s explanation and requirement to stay ABOVE the dew point is exactly right. You can find a discussion about HR cooling here:

GBT Radiant Cooling Discussion

If you live in a hot but dry climate, you can also use an evaporative cooler (AKA swamp cooler) in lieu of an air conditioner:

Borst Evaporative Cooler Performance Software

If you live in a hot and humid climate, you will likely need to use a dehumidifier or an air conditioner.

Ronmar, for a standard 2.5” EPS + 6” concrete + 2.5” EPS ICF build up using our 2013 Rogue River, Oregon outdoor temperature profiles, the ICF performance software forecast the effective R-value to be R21.38 in Spring, R66.15 in Summer, R63.42 in Fall, and R21.07 in Winter. This is an average annual ICF effective R-value performance of R43.07 or 1.86 higher performance than the conventional R23.10 R-value. These values agreed quite closely with the values determined from our actual building energy usage testing. We also had thermocouples in the concrete and the concrete temperature profiles also agreed quit well with the ICF performance software forecasts. Please also keep in mind that ICF can greatly reduce air infiltration which can also significantly improve performance. However, the software does not attempt to factor this into the effective R-value as this is better addressed separately by accurately forecasting the infiltration rate for a given building design and using this value and the ICF effective R-value in the ASHRAE or ACCA Manual J performance analysis.

After developing the ICF performance software, I exercised it extensively using some extreme ICF build up values. I don’t think there is anything earth shattering here, but the goal was to test and validate the software over a wide range of ICF build up values. Here is the excerpt from our ICF performance software instructions where I documented these observations at that time:

“Here are some ICF performance observations based on varying the various ICF design parameters from the calculator default values and using our Rogue River, Oregon indoor/outdoor temperature profiles:

When the interior EPS thickness is reduced to 0.1” and the exterior EPS thickness is increased to 4.9” (i.e., essentially putting all the insulation on the exterior side, but keeping the total conventional R-value the same), the summer effective R-value went from R66.15 to R44.05. In this case the concrete temperature stays very close to the indoor temp. The effective R-value remains the same (i.e., R44.05) when all the insulation is put on interior side. However, in this case the concrete temperature stays very close to the outdoor temp. This would imply that both these non-symmetrical ICF designs result in an equal, but lower performance than the standard, symmetrical ICF design for this summer outdoor temperature profile. When this is repeated for the winter outdoor temperature profile, the winter effective R-value went from R21.34 to R21.96, i.e., a slight performance improvement.

When both the interior/exterior insulation thickness is reduced to 0.01” (i.e., essentially removing the interior/exterior insulation), the effective R-value went to R0.77 (i.e., 1.12 times higher than the new R0.69 conventional R-value). This would imply that even an uninsulated, 6” thick concrete wall will exhibit some degree of increased effective R-value. When the insulation is retained, but the concrete thickness is reduced to 0, the effective R-value went to R22.50 (i.e., exactly the same value as the new conventional R-value). This would imply that as the concrete thickness is reduced, the effective R-value tends toward becoming equal to the conventional R-value. When the concrete thickness is then increased to 4”, the effective R-value went to R63.40 (i.e., 2.77 times higher than the new conventional R-value). When the concrete thickness is further increased to 8”, the effective R-value went to R67.79 (i.e., 2.91 times higher than the new conventional R-value). When the concrete thickness is further increased to12”, the effective R-value went to R69.99 (i.e., 2.95 times higher than the new conventional R-value). When the concrete thickness is further increased to 36”, the effective R-value went to R78.48 (i.e., 3.01 times higher than the new conventional R-value). When the concrete thickness is further increased to 360”, the effective R-value went to R177.12 (i.e., 3.03 times higher than the new conventional R-value). When the interior/exterior insulation is then removed from this 360” concrete thickness, the effective R-value went to R109.25 (i.e., still 3.03 times higher than the new conventional R-value). This would imply that as the concrete thickness is increased, the insulation thickness becomes increasingly less important in achieving the higher effective R-values. Furthermore, for this summer outdoor temperature profile, this would imply that the absolute maximum possible effective R-value is 3.03 times the conventional R-value and we are achieving 2.86 times the conventional R-value with a standard ICF design.

One might expect that higher effective R-values might be achieved by having some portion of the indoor temperature profile be the same as the outdoor temperature profile. For example, having that portion of the indoor temperature profile be the same as the outdoor temperature profile during the summer cooling season when the outdoor temperature is below 70 degrees Fahrenheit to simulate having open windows or using increased ventilation during these times. However, this is NOT the case. While doing this will reduce some of the Thermal Mass Temp output parameters, doing this will result in some of the Conventional Heat Flow Rate output parameters becoming 0 (where they were previously providing a building heat loss cooling effect), will reduce some of the Thermal Mass Heat Flow Rate output parameters (where they were previously providing more of a building heat loss cooling effect), will increase both the Total Conventional Heat Flow and Total Thermal Mass Heat Flow output parameters (i.e., provide increased building heat gain), but will increase the Total Thermal Mass Heat Flow output parameter more than the Total Conventional Heat Flow output parameter, and this will REDUCE the Thermal Mass Effective R-value output parameter. Doing this for the summer profile resulted in the effective R-value going from R66.15 to R39.06. One needs to keep in mind that this calculator only determines the effective R-value performance for just the ICF for the entered input/output temperature profiles and this calculator does NOT determine the HVAC system performance of the building. Or perhaps another way of thinking about this is that when you run the building AC system, the building cools down to a lower temperature than it would otherwise be, however, the heat transfer through the walls increases because of the increased inside/outside delta temperature. More thermal mass heat transfer is equivalent to having a lower thermal mass heat transfer resistance or a lower thermal mass effective R-value. Obviously, opening windows or increasing ventilation during the summer cooling season when the outdoor temp is below 70 degrees Fahrenheit is a good thing to do as this provides increased building cooling with minimum HVAC energy usage.”

Sailaway, I think you mean stay "above" the dew point? I knew you had to keep the fluid temp above the dew point, that's why I wondered about the use of refrigerant. Even unheated ground loop temps around here are almost always below the dew point but could be warmed with a mixing valve and heated water from the solar heat dump. I'd hate to pay to heat water for that use. What is the most energy efficient or best way of reducing the interior humidity in the summer - besides A/C? We have a shorter but still necessary cooling season up here and are fortunate to be able to take advantage of cooler nighttime temps for open window ventilation and cooling but only after lights out because we often have some small biting midges or gnats that locals refer to as "no see ums" that are small enough to penetrate the screens.