My Findings and Thoughts
Last Post 31 Jul 2017 01:32 AM by sailawayrb. 7 Replies.
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Dave WatersUser is Offline
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29 Jul 2017 05:48 PM
What an awkward interface.
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29 Jul 2017 05:49 PM
q
Dave WatersUser is Offline
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29 Jul 2017 06:16 PM
Hi guys,great forum with helpful folks and much yet to sift through. Sorry if this is too long but I am an infomaniac.
Brief history,when I was in my early 20s I lived in a northern climate and built an experimental earth shelter cabin using Passive Annual Heat Storage system. Thin shell concrete,rebar,screen,concrete floor, and it worked crazy well and from that I learnt that thermal mass=very good. Twenty plus years later,I own canal properties in SW Florida and will retire there soon enough. I never really heard of SCIPS until very recently,after researching blocks,ICF,etc ICF is the most heavily advertised,and I liked the wind and fire qualities BUT why have the concrete on the inside not contributing to thermal mass?

My house will be a single level U shaped house-about half of it a car garage.I have too many cars LOL. Very simple design-the outside walls 9' high,the interior wall to the courtyard will be glass with necessary posts/beam 12' high.Width of the living areas about 20 feet. The courtyard will have a wet bar,hot tub,pool,trees,wet bar,plants,outdoor kitchen and I should mention it'll have a wet bar.Basically be a jungle.I want a monolithic building including roof,insulated to beat hell. 20 kw of solar on the roof.

My findings,in brief. Will skip the SCIP companies.

A. Found a block company,massive blocks 7" concrete with 4" of foam but they have the concrete on the outside. Holes through,anchored and grouted to each other a very stout building but no thermal mass on the inside. And they don't do gables so it looks goofy with different material gables added on. I emailed them,asking if they can angle cut the blocks to do gables, put on a SCIP roof,,and build the house reverse (concrete inside-insulation outside) of how they propose...never heard back LOL! .

B. ICF. We all know the properties.

C. Found another block company, they have it right in that foam is sandwiched between concrete skins and no thermal bridges BUT how to do gables,monolithic roof as is no way/stupid to drill out room for rebar in those bricks. And they are built with a grout layer,so a thermal bridge.

D. Another block company,advertising 3 layers of concrete and 2 of foam BUT the bottom quarter of the block is solid concrete so....bridging.No gables.

E A tie company,using non thermal bridging plastic ties however it seems you basically build a wood house,trusses and all and then skin it all in concrete and end up with a stout house but...no interior thermal mass and you are basically building 2 houses in one..

F. Found a tie company in the UK using plastic ties instead of wire ties,but don't know if they are approved for US. Wire ties go through the foam,but they attach to the wire screen with a plastic knob thingy.

G Then I was thinking along other lines...why not just pour a house? there's a company that does aluminum forms,quick easy forming..Pour a 5" house and spray a foot of foam on the outside, SCIP roof and ,then water proof sheet the outside but seems a lot of hassle and too many possibilities for water ingress.

H. Another company using quick forms,basically it's a SCIP house but poured.,they don't form the roof.

Thats my findings,SCIP is the way to go but my one thought is the thermal bridging caused by the wire ties. It seems ICF people criticize SCIPS for that but we all have windows (ICF too) and I'd suspect that the windows bleed multitudes more than a small area of wire ties. All the area of those little wires coming through will be what...a couple square inches per 4x8 section? I'm not too concerned with it,as I'm going to have a ton of multi pane glass which will bleed more than a few wire ties,but am curious if anyone has ever built a 6x6x6 cube with regular steel ties and a twin with plastic ties,and done any testing/ FLIR viweing. Anyways,thanks for reading my findings and thoughts. If anyone wants links to my findings Ill post them and try to be helpful.
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29 Jul 2017 10:22 PM
TF Systems uses a vertical panel ICF system and they have an option for leaving the interior surface exposed concrete. However, I don't see any issue with just using standard EPS sandwiched concrete core ICF block which certainly provides a thermal mass effect. We have an ICF performance calculator on our website to accurately forecast what the effective R-value will be given your seasonal daily temperature variation.
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DilettanteUser is Offline
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30 Jul 2017 02:34 AM
Also, where did you get the idea that ICF of concrete under insulation DOESN'T contribute to a thermal mass effect?

The insulation prevents uncontrolled thermal bridging of the interior/exterior environment directly to the concrete layers. So the concrete heats and cools at a more controlled rate.

With something like Spider-Ties and SCIP, you have differential expansion and contraction rates between the outer concrete shell, the insulation core and the inner concrete shell.
Over time, depending on the severity of the heating and cooling cycle, this could lead to spalling and delamination of the wall.

The main problem with spraying onto exterior concrete is that there's no real, good way to get an even wall at that point,

Now, if you're building some art nouveau structure with a semi-organic, non-square exterior, knock yourself out.

If you're spraying foam, and then having to chop it down level/even, you're wasting money in both time and excess product. You're better off using sheet insulation.

But there's nothing stopping you from doing a "roll your own" pseudo-ICF setup with a standard concrete wall with sheet on the outside and spray on the inside.

It generally just comes down to which can deliver your desired end in a more economical manner.
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30 Jul 2017 04:54 PM
Very true. With conventional ICF during the summer months in our southern OR diurnal climate (often a 40-50F high/low daily temperature difference) we are experiencing an effective R-value of R66 (2.9 times higher than the conventional R-value) and this is entirely the result of the thermal mass effect. Of course, ICF also makes it easy to reduce outside air infiltration too, but that is a separate subject. Even when we have 110F days, the inside temperature stays below 70F without any need or use of AC.
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Dave WatersUser is Offline
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30 Jul 2017 08:50 PM

"TF Systems uses a vertical panel ICF system and they have an option for leaving the interior surface exposed concrete. "
At least you offer INTMASS which is better than ICF,but you still have a horse in the race.


Then:

"Also, where did you get the idea that ICF of concrete under insulation DOESN'T contribute to a thermal mass effect?
The insulation prevents UNCONTROLLED thermal bridging of the interior/exterior environment directly to the concrete layers. So the concrete heats and cools at a more controlled rate.
With something like Spider-Ties and SCIP, you have differential expansion and contraction rates between the outer concrete shell, the insulation core and the inner concrete shell.
Over time, depending on the severity of the heating and cooling cycle, this could lead to spalling and delamination of the wall. "

So the ICF core does act as a very useful thermal mass,and therefore heats and experiences a temperature differential and it's no problem. But when CIC does, the house may need to be torn down? Really?
Nowhere did I state I was going to spray foam,causing myself extra work. But then you propose ICF which needs both interior finishing and external waterproofing and finishing. Interesting take.

"It generally just comes down to which can deliver your desired end in a more economical manner."
I don't care about spending a bit more on the house.

And more sales:
"Very true. With conventional ICF during the summer months in our southern OR diurnal climate (often a 40-50F high/low daily temperature difference) we are experiencing an effective R-value 2.9 times higher than the conventional R-value and this is entirely the result of the thermal mass effect. "
With the implication that CIC doesn't.
Interestingly the graphs from ORNL show ICI( ICF) at 1.6 times the R rating in hot climates and NOT 2.9...but it does show CIC/INTMASS at 2.8 times. Is there some new graph out where someone switched the names around?

ORNL:
“This data shows that the most effective wall assemblies were walls with thermal mass (concrete) being in good contact with the interior of the building (Intmass and CIC)”

"“Wall configurations with the concrete wall core and insulation placed on both sides of the wall (ICI)/ICF performed slightly better than Extmass (foam on inside) configurations. However, their performance was significantly worse than CIC/SCIP and Intmass configurations. “




BTW I did notice that both of you ignored my question/observation about windows having multitudes more effect than a few ties...
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31 Jul 2017 01:32 AM
We don't have a horse in any race and we don't sell ICF or any other products. We accomplish commercial and residential engineering design and construction specializing in passive solar and hydronic radiant floor cooling/heating.

ORNL test data is always worthwhile and interesting, but it is limited in scope and actual application like all test data. Thermal mass effect on effective R-value depends on the actual indoor/outdoor temperature profiles which is why a computational analysis is more accurate and appropriate for forecasting ICF performance for the actual seasonal daily temperature variation that it will be used. If we used ICF in our southern OR summer climate with all 5" of the EPS insulation on outside surface and no EPS insulation on inside surface, the effective R-value would decrease from R66 to R44 (only 1.9 times higher than the conventional R-value). And please be advised that no matter what thermal mass product you use, the thermal mass effect tends toward zero as the seasonal daily temperature variation tends toward zero. Maximum effective R-value occurs with large seasonal daily temperature variation centered about the indoor temperature.

Even the best windows are far worse than the worst walls in terms of R-value and windows should be minimized in energy efficient buildings. However, outside air infiltration is often a larger performance hit than windows. Using ICF makes it easy to minimize outside air infiltration. Ties are certainly far less significant than windows and outside air infiltration, but why have them at all if they can be completely avoided.

It sounds like you have already made a decision and you are not really all that interested in our guidance/suggestions. Good luck with your project.
Borst Engineering & Construction LLC - Competence, Integrity and Professionalism are integral to all that we do!
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