ICF addition
Last Post 22 Apr 2015 02:58 PM by emmetbrick. 10 Replies.
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dedoUser is Offline
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13 Apr 2015 08:57 PM
We are thinking of an addition to our wood frame, brick veneer home in Virginia Beach. The idea of having at least part of our house to be hurricane resistant is attractive. Can you attach an ICF wing (~300 SF) to a wood frame brick home on a crawl space, and cover it with the same brick so it looks like part of the original house? We are still researching ICF. One concern is that the weight of the addition would be much more than the main house. Would the ICF wing sink, leading to cracks where the new brick meets the old? Of course we would use an architect recommended by an ICF builder. However, we don't want to mess up our original house in the process of trying to improve it. Thx
eiland29User is Offline
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13 Apr 2015 09:34 PM
It would work great.
Chris JohnsonUser is Offline
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13 Apr 2015 11:43 PM
Proper engineering will eliminate the 'sinking' of the new wing, as well the engineer will dictate connection details between the new and existing structure.
Chris Johnson - Pro ICF<br>North of 49
gosolarUser is Offline
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14 Apr 2015 04:25 PM
Sinking is a function of the footings and foundation being build to code and soil type.

It should work fine, call a local architect and just talk about your idea
billnaegeliUser is Offline
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14 Apr 2015 05:55 PM
do them all the time-additions to an existing wood house are not a problem at all, i would recommend an architect that is familiar with ICF though, if not they will probably try and talk you out of it.
GNP Inc
ICF Construction & Concrete Services
1-800-713-7663
dedoUser is Offline
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15 Apr 2015 08:50 AM
Thanks.

It sounds like it is no more risky than a wood frame addition if you are working with people experienced in ICF (architecht, builder, engineer).

The architect was recommended by an ICF builder. Once we get sketches, we will get bids.

The backup would be steel sips which I hear any builder can work with if a factory certified team does the frame.

My first choice would be ICF if the bids are not way beyond the alternative (steel sips), and if references are similar, otherwise steel sips.

I am wondering if ICF walls with a wood roof offers any real structural advantage over steels sips. It seems that to get the maximum gain from ICF, you need an ICF roof as well. Does this make costs soar, and can an ICF roof be covered with normal roof shingles to match the existing roof?
billnaegeliUser is Offline
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15 Apr 2015 11:56 AM
you are correct , we usually spray foam the roof system, that achieves the best results for ICF structures
GNP Inc
ICF Construction & Concrete Services
1-800-713-7663
RafiUser is Offline
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15 Apr 2015 12:24 PM
@billnaegli: When you sprayfoam under the roof, do you usually go with the open cell or closed cell? Closed cell is so extremely expensive. Our city requires R-38 value. With the open cell foam we would need appr. 8 to 9 inch of open cell spray foam thickness. That is a lot, the estimates came back with 5.5 inch, which is the thickness of a 2x6. What is common with residential homes these days?
LbearUser is Offline
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15 Apr 2015 08:10 PM
Posted By Rafi on 15 Apr 2015 12:24 PM
@billnaegli: When you sprayfoam under the roof, do you usually go with the open cell or closed cell? Closed cell is so extremely expensive. Our city requires R-38 value. With the open cell foam we would need appr. 8 to 9 inch of open cell spray foam thickness. That is a lot, the estimates came back with 5.5 inch, which is the thickness of a 2x6. What is common with residential homes these days?

Open Cell per inch = R 3.5 avg

Closed Cell per inch = R 6.0 avg

OPEN CELL is vapor OPEN or permeable while CLOSED CELL is vapor CLOSED or impermeable (based on total approx thickness of course).

Code calls for R-38 minimum so that would be 10" of open cell or 6" of closed cell in order to pass inspection code. That is the bare minimum in order to pass code but most say that R-49 should be the minimum in an energy efficient home. The 2012 IECC requires R-49 minimum in the roof/ceiling in Zones 4+. 

If you only do 6" of open cell you would be at around R-21 and the county/city inspection would fail it. Closed cell at 6" would bring it close to code at R-36 and close enough to R-38 that it would most likely pass inspection. Not to mention that an R-21 ceiling would contribute to higher energy bills.

Open cell carries a slight risk because if the ceiling is not done 100% correctly, any air leaks can cause water vapor drives inside the home to rise and when it hits the roof sheathing, it can condense and create moisture/rot issues.

I believe closed cell is the better product but it all depends on the climate location, roof sheathing, house design, vapor barriers, etc.




BrucePolycreteUser is Offline
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16 Apr 2015 11:39 AM
Dedo, Just sent you a private message.
Bruce
emmetbrickUser is Offline
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22 Apr 2015 02:58 PM
We do it all the time. With a brickledge block you can also accommodate any elevation changes your grade may present. Full Speed Ahead.
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