Traditional panels vs ICF concrete walls
Last Post 16 Feb 2014 09:13 AM by DerekLewellynTanner001. 14 Replies.
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MitchellConcreteUser is Offline
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28 Jan 2014 03:37 AM
My family business has been doing traditionally poured concrete foundations / walls in western Massachusetts for 25 years. For 25 years we have been using the old, heavy, wooden panels for 4ft and 8ft walls. ICF's have sparked my interest a bit, and was curious if people could answer some questions or point me in the correct direction. Can ICF's be used for residential house foundations, e.g. 4ft and 8ft walls, usually 8 and 10 inches thick? With experience in traditional pouring of concrete, will the transition to ICF's be smoother? Or is this an entirely new ball game? What would be the typical, rough cost of an ICF foundation wall 20x40 8ft high and 10 inches thick? Using the concrete panels I have requires a lot of man power, and of course having to strip the foundation as well - but of course come at no cost. I was curious to see if the company can make a transition to ICF's smoothly, if it is ideal for residential foundation walls, and if it is cost efficient. I'm sorry if this is not in the correct place, or if this has been asked a hundred times. I look forward to reading your responses, and appreciate them. Thanks for reading.
jdebreeUser is Offline
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28 Jan 2014 08:07 AM
I can answer some of your questions. An ICF wall is essentially a poured concrete wall- the main difference is foam forms instead of plywood. ICF's are available in different core thicknesses. The process of filling them is similar, although consolidation is tricky because there's a bit more stuff in the way with the webs. Most forms don't recommend filling all the way to the top in one shot, but rather, filling in 3' lifts, working your way around. Usually, the starting point will be set enough by the time you work your way back to it for another lift. Another reason proper consolidation is so important is that you can't see the finished results, since the forms stay in place. I would think with some training, and following the manufacturer's instructions exactly, it shouldn't be much of a learning curve.

Stacking the forms is very easy, but there are things to learn about proper bracing and securing the blocks to prevent floating. Window and door openings use a system of bucks, and these openings have to be properly braced. You already know how important it is to get openings right, as they are hard to fix later. I did all the work on my own home, but hired an expert to do the filling. I watched the whole process; it certainly isn't rocket science. I'm not sure about poured foundations, but with ICF, you want a really level footing to start with- it will save you trouble later on.

I don't really know much about cost, but I have seen numbers like $12-$15 per square foot of wall area. That's what you would pay a contractor, so I don't know what the actual contractor's cost is. I'm sure ICF is more than poured concrete, but you are getting (IMHO) a vastly better product, since the walls are already heavily insulated, and you are ready for wall coverings, inside and out. You can calculate the materials easily, using the price of the blocks (FOX has their's right on this page), the block suppliers have calculators to figure concrete usage and rebar. Some of the pros on here can give you an idea of labor costs. If you were going to do ICF as a contractor, you'd want to invest in wall braces. I'm not sure what they cost, but it could be a significant investment. Once you figure out your cost, you would need to figure out whether your customers will be willing to pay for it.
Dana1User is Offline
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28 Jan 2014 11:47 AM
From a foundation cost point of view it'll still be cheaper to just pour concrete, but from an INSULATED foundation point of view on projects were time is money, even though it's a more expensive foundation it's usually going to work out in the GC's favor to go with an ICF than adding a second task to the insulation crew.

Like anything there's a learning curve- you'll want to pour some slab on grade stemwalls and crawlspace/basement foundations before extending skyward with them. The cost rationale for ICF on the upper stories isn't usually going to be there on thermal performance grounds in a MA climate, but there's a lot to be said for the structural aspects of building with concrete. Even the thinnest ICFs available exceed current MA code min on steady-state R value, and are significantly above code for a minimalist mass-wall-R. (Current code-R in MA is IRC 2009 for climate zone 5: http://publicecodes.cyberregs.com/icod/irc/2009/icod_irc_2009_11_sec002.htm )

ICFs aren't rare in central MA- an addition in my own home (zip 01609) was done with an R16-ish ICF back in the mid-1990s (apparently by a bit of a hack, who didn't tie it into the existing foundation in an air-andwater-tight fashion- there have been some issues...), and the "This Old House" folks are often heard plucking the ICF harp on their (often in MA) project houses.

ICF foundations work well with higher-R framed walls that use insulating foam sheathing over the structural sheathing, since you can align the exterior plane of the framed wall sheathing foam with the exterior EPS of the ICF for a continuous thermal break over the thermally bridging concrete at the top of the foundation. Insulating foundations from the interior usually leaves some thermal bridging at the foundation sill and band joist that is difficult to design-out adequately for high-performance homes.

Code min basement walls in MA is R10 continuous insulation/R13 if thermally bridged by studs. That's about half the R of most ICF vendors' thinnest product these days, so it IS a significant performance upgrade for a foundation wall, but not an over-the-top rediculous foundation R for a MA climate. On a lifecycle basis it still pays for itself in energy savings in this climate, but much of the returned value is up-front, in the accelerated project schedule.
smartwallUser is Offline
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28 Jan 2014 01:16 PM
In New York the IBC r-16 is the norm. Also the ability to pour the footing and wall in one pour is also a big time saver. The lightness of the forms makes this possible when compared to a standard set of forms
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28 Jan 2014 01:34 PM
Posted By smartwall on 28 Jan 2014 01:16 PM
In New York the IBC r-16 is the norm. Also the ability to pour the footing and wall in one pour is also a big time saver. The lightness of the forms makes this possible when compared to a standard set of forms

R15 basements would only be code min under IRC 2012- which SFAIK is not currently law in NY (which is only at IRC/IBC 2006 state wide but at IECC 2009, which spells out R10 c.i for basements for zone 5, R15c.i. for the climate zone 6 parts of NY only.)  See:

http://www.iccsafe.org/gr/Documents/stateadoptions.pdf

http://energycode.pnl.gov/EnergyCod...=New%20York

When pouring a footing and wall I'm not clear on how easy it is to put a capillary break (like EPDM or 10 mil poly) under and up the sides of the footing, to avoid wicking ground moisture up into the foundation wall.

Done in separate pours it's common to put the capillary break between the footing and the wall. Since it's not demanded by code, it's a performance detail often omitted altogether, but it takes a significant bite out of the moisture burden of a house.  Tighter higher-R houses will often need measurably more mechanical dehumidification without capillary breaks at both the footing & slab.
arkie6User is Offline
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28 Jan 2014 02:37 PM
Posted By Dana1 on 28 Jan 2014 01:34 PM

When pouring a footing and wall I'm not clear on how easy it is to put a capillary break (like EPDM or 10 mil poly) under and up the sides of the footing, to avoid wicking ground moisture up into the foundation wall.

One option is FastFoot footing fabric.

Fastfoot also has a mono-pour option for ICF:  http://www.fab-form.com/fastfootMp/...erview.php
AltonUser is Offline
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28 Jan 2014 03:26 PM
At one time, some ICF manufacturers were producing forms that could contain more than the nominal amount of EPS.  If these companies are still in business and producing super-insulated forms, then more R-value could be useful for areas with severe weather.

If ICFs are too expensive for you market and you want much more R-value, then look at Structural Concrete Insulated Panels.  I have used them without any significant problems.  You will need at least one certified nozzleman to produce walls with a gun finish that will require no more facades.  Having to add finishes to both sides of a wall can really increase the total square foot cost for the building.
Residential Designer & Construction Technology Consultant -- E-mail: Alton at Auburn dot Edu, 334 826-3979
JosephFearnUser is Offline
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28 Jan 2014 05:13 PM
Fastfoot is designed to form the footing, and prevent rising damp in concrete. Here is a link to a video on Rising Damp; http://www.youtube.com/watch?v=w6iiwvi1tx4
HamptonsICFUser is Offline
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28 Jan 2014 05:22 PM
We pour footings and walls at same time, have used Fab Form but it is finicky and can have settling due to holding the forms up in the air while concrete weight adds pressure. I use a Polycrete form as footing with what ever thickness is required then go up with the smaller form even if its not Polycrete. they stack very fast because they are 8' long, even if you don't pour the whole wall and just do a couple rows you will eliminate nearly all water intrusion, as a vast percentage of water comes in under wall through the keyway.
Its always easier to teach a carpenter to do ICF than most masons as they are used to the finer measurements, like subtracting stucco etc etc to get the proper window opening for CCA.
You will have a learning curve but its all good you will be offering a far superior product, welcome.
Contact us at 631-725-2404 info@HamptonsICF.com
MitchellConcreteUser is Offline
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28 Jan 2014 06:07 PM
Wow, thanks everyone for the awesome replies. Going to continue to do some more research and see if it is something worth investing into.

As for the basement wall, we usually do 8ft walls 8 inches or 10 inches thick, and the contractor usually will put whatever insulation, usually foam.

Shouldn't that be fine in terms on insulation of a basement while the in ground temperature doesn't go below 45 degrees?

Or does building an ICF basement wall have more advantages that I can't see? One thing I can think of is it being less labor. But I assume the cost of ICF would be more?

Also pouring the footing and wall at the same time to avoid leakage through the keyway is something I didn't know was possible. Interesting.

billnaegeliUser is Offline
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28 Jan 2014 06:48 PM
another option might be to just pour the footer first like normal, then what we do sometimes is place 1 or 2 blocks(usually with drywall track on one side of the form) then prep the slab and pour a portion of the first 1 or 2 icf blocks then drop the hose inside to pour the slab, you usually always have to pump a slab pour, especially if it is a basement, that gets us out of the mud and we dont have to worry about the bracing moving around as much if we are bracing to dirt(mud), just an idea/option
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28 Jan 2014 07:10 PM
Posted By MitchellConcrete on 28 Jan 2014 06:07 PM
Wow, thanks everyone for the awesome replies. Going to continue to do some more research and see if it is something worth investing into.

As for the basement wall, we usually do 8ft walls 8 inches or 10 inches thick, and the contractor usually will put whatever insulation, usually foam.

Shouldn't that be fine in terms on insulation of a basement while the in ground temperature doesn't go below 45 degrees?

Or does building an ICF basement wall have more advantages that I can't see? One thing I can think of is it being less labor. But I assume the cost of ICF would be more?

Also pouring the footing and wall at the same time to avoid leakage through the keyway is something I didn't know was possible. Interesting.



CIP walls that are normally 8" thick are usually placed as 6" core ICF. The ICF's all use rebar to get the strength that is required. Rebar is cheaper then concrete so you have a 2" concrete cost saving to offset the cost of the forms. In some places where 9" walls are the norm, 6" ICF is used with the appropriate rebar and the cost is near the same and for a much better product.
smartwallUser is Offline
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29 Jan 2014 08:05 AM
Most of my pours are zone 6. I have yet to see anyone doing a capillary break in a traditional poured wall. Last year we did a couple of mono pours which included the floor as well. My flat work guys love using the pump to pour the floor. The Fastfoot is an excellent system but I created my own system that allows me to pour the footing walls and floor in one shot. Most icf walls are either 8" or 6", the slow set of the concrete creates a stronger wall with a thinner profile. The picture that accompanies my post is from a mono pour of a walkout basement I did in 2006. I try to sell the basement as living area and not just a place for the HVAC and water heater. Egress windows, dry wall ready, you would have to have rocks in your head to not utilize the space. Plus because it's in the ground it has a much better thermal situation than above ground. -13 degrees F this morning in upstate NY
BrucePolycreteUser is Offline
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06 Feb 2014 04:51 PM
If you want more EPS insulation in your ICF wall, take a look at PolycreteUSA's R-Stak inserts, we add EPS inside the ICF core. Standard thicknesses are 2.5" and 4", so you can easily get 7.5" and 9" of EPS insulation in your wall. Fastening strips remain close to the surface for easy screw attachment. Theoretically, we can give you as much as 23" of EPS on a 6" wall. Not sure why you'd want that much, but that's our upper limit.
DerekLewellynTanner001User is Offline
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16 Feb 2014 09:13 AM
I have used plywood forms for years and about five years ago made the transition to icf. As our energy codes have been changing and we need the extra insulation for basements it seemed a good time to change.I have used a few different block systems and Quad Lock was my first.It offers the most options as I am a custom home builder.The cost as compared to stick frame is very close but the benefits far out way the cost.I can build a high and straight wall and it will stay that way forever.Our cabinet guys love the walls as they are much more consistent than stick walls.I recently poured a 20 foot wall with only 1/4 variance in 60 feet,do that with dimensional lumber.We also have the option of doing monolithic pours in wet areas.I love the product and our company only builds icf homes now.
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