Pitched Insulated Concrete Roof Taboos!
Last Post 23 Mar 2022 04:51 PM by insuldeckflorida. 60 Replies.
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ICF372User is Offline
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25 Feb 2009 11:33 AM

I guess I should have been more specific. When I referred to exposed concrete.  I really was referring to concrete not covered with insulation on the outside.

This 14 year old lad we picked up in the local town just need some extra cash, he is installing one of the more critical parts of this system. It's actually quite simple. If fact no one on this project had ever installed a ICF other than myself.

 



Eldon Howe
Howe Construction [email protected]

Total Concrete Homes provide positive cash flow , DAY ONE .
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25 Feb 2009 11:47 AM
We are using speed floor composite floor joist as rafters in conjunction with a standard 4" IntegraSpec panel.

The rafters are 4' on center. The foam panels rest directly on the lock bars, add re-bar and that's it.
We used up a lot of waste on the bottom side, and I mean a lot of waste. These guys drove over forms broke forms and just simple made a lot of waste. So we used it up with out any regard to size. You can see the numbers many were salvaged cuts  such as:  6-1-6.  The 6 stands for 6" of foam, the 1 stands for the plastic stud location and the 6 is for 6" of foam.

You could also use a wood stud center wall for the ridge support much like the Sip folks do.


Eldon Howe
Howe Construction [email protected]

Total Concrete Homes provide positive cash flow , DAY ONE .
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02 Mar 2009 11:10 PM
Posted By rhinojosa46 on 02/10/2009 1:56 AM
Robincc.....Yes that bother me too, but in most cases that they use the WRCS roof they reinforced the walls #5 @ 16" O.C. anothers Fill all the cells. For me is more sense having an ICF system than CBS, but don't worry they are changing, change ppl mind is not easy. Was a challenge also introduce this kind of roof instead of Trusses (I know is obvious) but like I told you is not easy change minds. They are now using the ICF walls together with the roof, in fact there are big houses permitted being build this year using ICF walls and WRCS floor and Roof (I will post more pics of those houses later, when they start). Regarding the stair, this is typical formwork and a liittle of engineering :) . I will post a pic of one formwork example. Regarding the price I've seen contractors expending anywhere from 8 to 14 per sq. ft of roof (Panels, shoring rental, shoring labor, overhang formwork, panel placement, reinforcing labor, concrete, pump and conc. finishing), of course this range is because pitch, roof complexity, double heights, etc.

Those panels are precut on the manufacturing plant to size according the project, with angles on ridges valleys and bevels. There is no need of crane one man can handle a panel of 20'. After the shoring is set, they set the panels with the shape of the roof, then the reinforcing and later they pour low slump concrete with fiber, from 3000 to 5000 psi depend of the project and location. After seven day they remove the shoring, and you have a perfect heaven cathedral concrete roof, ready to any kind of exterior finish and ready to install any kind of interior shape that you can imagine.

pcouling....Beleive it or not, is not expensive. Is about the same price of built an straight concrete stair. The labor is a little more skilled but other than that, everything remain almost the same.

Regards,

Raul

Raul,

What kind of fiber are you using?


Jeff
Green Oaks Building & Remodeling
www.greenoaksremodeling.com
Buddy NewberryUser is Offline
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03 Mar 2009 11:30 AM
I think this is a very goodlooking roof system that you have posted Raul. However, after reading the responses posted in this forum and checking out the slideshow of Eldon's project I would have to say that an ICF roof system is the way to go.

I believe this mainly for one reason, it would appear that roof you have shown here has exposed furring strips on both the top side and under side of the roof system. In having exposed furring strips such as this the overall R-Performance of the system will be adversely affected because of the thermal bridging that may take place at this connection point. Along with thermal bridging the threat of condensation may present itself in the possible creation of a dewpoint transfer.

If the residents are running air conditioning inside the house and the warm temperatures of the Southern sun are beating down on the roof, the thermal bridging that can be caused by the exposed furring strips (even though they will be covered) will let these two apposing temperatures meet and create condensation within the roof. the system that Eldon is showing negates this possibility because the strips are within the panels. As well, it seems as though it would provide greater structural stability in conjunction with the wall systems because there is the option of a monolithic pour between the two applications.

Here is a picture I took from the website, very impressive Eldon.

Buddy,  

Attachment: 25.jpg

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03 Mar 2009 08:47 PM
Has anyone done a pitched roof with Lite-Deck or Amdeck?


Brad Kvanbek - ICFconstruction.net
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04 Mar 2009 07:12 AM

for the past 8 years....

email me for info...

[email protected]



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07 Mar 2009 09:07 PM
Insuldeck, Do you have some photos you could post? How is the shoring done?


Brad Kvanbek - ICFconstruction.net
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10 Mar 2009 06:12 PM
Just started working on a simple 30' x 30' TICFS  that has a 2ed level with clearstory windows supporting a concrete ICF roof.  I hope this one leaves the drawing board.
It also uses a air heated Frost protected foundation. See www.legalett.com

The entire roof is unshored durring the pours. The speedfloor joist support the entire wet concrete load.

It will be earth bearmed half way up the second level. And support a living earth green roof.


Attachment: New Solar 2.jpg

Eldon Howe
Howe Construction [email protected]

Total Concrete Homes provide positive cash flow , DAY ONE .
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11 Mar 2009 11:18 AM
What type of concrete, slump and reinforcement are you guys in michigan and florida using for the concrete roof to avoid cracking and wear over time.


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11 Mar 2009 01:01 PM
our engineers seem to spec 3000 to 4000 psi, pump-mix most of the time....
slump same as a concrete slab/driveway, so it easy to finish...
rebar is anything from [email protected] #5 to 2 @ #8 depending on span and load.
cracks are handled by sealling the contrete after it has cured (and cracked) with a liquid membrane type system or fastening a traditional roof over it.
personally, i live in a flat and 3/12 pitch insuldeck/polysteel house with raw concrete roofs that are 3 and 4 years old.
some surface cracks, no leaks below.
when i am all done with the remaining construction i will seal the roofs and decks with something like these...
http://www.ccwcompanies.com/ or sonneborn/sonoguard liquid applied coatings, easy do it your self stuff, just need to clean/pressure wash the old surfaces first....

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11 Mar 2009 02:46 PM
I have heard that using 5000 PSI concrete which can include fly ash will make the concrete more water resistant.  I would imagine that the extra cost for a richer concrete mix is hard to justify.


Residential Designer & Construction Technology Consultant -- E-mail: Alton at Auburn dot Edu Use email format with @ and period . 334 826-3979
Raul HinojosaUser is Offline
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11 Mar 2009 03:49 PM

On the WRCS system we use fiber in the mix and low slump blend mix, actually most of the concrete roofs call for 3000 psi, although some use 4000 to 5000 psi because proximity to water and different water cement ratios. A good curing process and fiber in the mix will increase drastically the strength of the concrete and prevent most of the cracking. You can pour 8:12 pitch using more or less this kind of mix using the WRCS concrete roof system we have not see any crack in the concrete roof. 

Raul 



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11 Mar 2009 06:57 PM
 It dose not take a lot of heavy steel In a composite concrete floors and  roofs. Mostly a heavy gauge welded wire mesh is used.
For a composite ICF roof we can't install the wire mesh within the ICF cavity. Instead 3/8" rod is used horizontally on 12" centers and 1/2" vertically on 16" centers. It all depends on the engineering.

 3,000 psi concrete is all that is necessary and keep the slump under 4". On shallow pitched roofs higher slumps are used and the Portland content is increased to maintain the 3,000 psi.

 The joists carry all of the wet concrete load, with 4' of concrete on either side of the joist and no shoring or propping. This means the actual concrete span is only the 4' between the joist. It don't require a lot of reinforcing for a 4' concrete span.


Eldon Howe
Howe Construction [email protected]

Total Concrete Homes provide positive cash flow , DAY ONE .
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11 Mar 2009 07:10 PM
ICF 372 Have you used hambro for a flat roof? Were you able to cantilever (extend) the roof beyond the outside wall. Did you just use the same rebar as you would if you were doing a floor? Thanks


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11 Mar 2009 09:35 PM

We have used Hambro for floors but not for roofs. It will work fine.

Cantilevers will to be engineered. My concern is the truss webb will need to be painted every few years or you could have a structural problem.

This photo is a speed floor flat roof. The shoring to the right is for the 32' dome on top of the roof.



Eldon Howe
Howe Construction [email protected]

Total Concrete Homes provide positive cash flow , DAY ONE .
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12 Mar 2009 08:43 AM
How about pictures of pitched roofs with Lite-Deck, Insul-Deck or Amdeck?


Brad Kvanbek - ICFconstruction.net
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12 Mar 2009 09:15 AM
Lite-Deck has been very successful for pitched concrete roofs. Please contact us for more information.
Thank-You,
David Hall
Lite-Form Technologies.
1-800-551-3313



Please contact me regarding information on Lite-Form ICF systems including, Lite-Form, Fold-Form, Lite-Deck or Lite-Deck Tilt.
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13 Feb 2022 04:17 PM
Hoping to resurrect this discussion and hear if there has been any advancement or improvements in the use, construction techniques, and feasibility related to steep pitched concrete roofs in conjunction with homes with 100% ICF wall and floor construction?
- I know most have said it isn’t feasible but that doesn’t negate the fact that it is a sound principle. There are a number of advantages.
- The issue that comes to mind when I think about it, is how to contain the concrete with an open design like quad deck, lite-deck, and similar?
- I would like to hear thoughts about using ICF wall forms in conjunction with concrete deck forms with built-in girder system to help retain the concrete and reduce thermal bridging, as well as, provide a insulated, water resistant membrane between the concrete cores, soffits, facia, etc… and providing attachment (embedded firring strips in ICF) for final roofing layers, such as a standing seem metal roof or decorative concrete tiles.
- I would be curious what kind of engineering would be necessary and if there are any prescriptive methods available
- My thought is that if there was a pitched roof system, better than the WRCS (wind resistant concrete systems) currently in use, that allowed for any pitch (8/12, 12/12, etc…) instead of low-pitch, better attachment points, and prescriptive engineering designs from ICF mfgs, that held in the concrete like a wall form and included soffit and facia profiles… it would be easier to install and better accepted.
Just a few thoughts…. I would like to hear everyone’s arguments for or against such improvements.


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22 Mar 2022 08:27 PM
This thread, though old benefited my understanding.
I am planning to build a small single story home in SW Florida, using FoxBlocks and InsulDeck (flat roof).
I did the initial model to convey the design my family wanted and now architect is working on it.
Please see the front rendition image.
Ten years since this original discussion... Any one of you regret having an ICF roof?
Thank you!


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22 Mar 2022 08:44 PM
Sorry forgot the attachment

Attachment: 4_.png

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