You might want to use galvanized rebar if you plan to leave it exposed.  Rusting rebar can destroy concrete.

For cheaper quieter roof, than concrete, look at conventional framed roof with open cell spray foam on underside of roof deck, and also above the ceiling drywall. Closed cell foam willl conduct more sound energy, as will concrete. You are looking to solve conductive sound, while dealing with convective energy loads/losses.
Use of foam in the attic depends on your latitude, degree days, humidity, so do your research for where you are building....

Any pitch can be built. You can use standard ICF forms and pour 12/12 pitches, the steeper the better.
We can span up to forty feet.
See the video with a 12/12 pitch. http://youtu.be/qqIDK6P2TXU

Eldon Howe
www.totalicfs.com

Posted By ICF372 on 16 Sep 2013 03:24 PM
Any pitch can be built. You can use standard ICF forms and pour 12/12 pitches, the steeper the better.
We can span up to forty feet.
See the video with a 12/12 pitch. http://youtu.be/qqIDK6P2TXU

Eldon Howe
www.totalicfs.com

I saw a lot of vibrating going on with the stinger, which is a good thing.

Ballpark, what are the costs for the ICF roof? I was told around $23+ per square foot of roof area.

Have you ever done overhangs in concrete/ICF?

Indeed it can be done but it is a rare bird, that is for sure. Not too many ICF contractors out there can do such roofs.

Where was that home built?

The house in the video is in Ireland. Our prototype is in Michigan and had a 5.5/12 pitch with a small turret.

The cost will be $20 and up.

A few years back I helped build a ICF/ speed floor roof Hotel in Tifton GA. Only a stones through away from the expressway 75. This Comfort Inn Suites won an ICF award in 2007 and is highly rated for it's quiet rooms, on trip advised. We completed a 6 story Holiday Inn in Peekskill NY with a hollow core precast roof last winter. We'll see how it preforms.

Theses roofs are built with standard ICF panels that are mostly unaltered.

Here is another option.

It would be interesting to see some actual sound level data from concrete roofs and some of the well designed but lower cost alternatives. Certainly some of the latter outperform concrete.

Yes it would. I have a limited budget for such testing. However the sound testing provided with the ICF you use is what you get in a icf roof. It's really do different than the walls.

You could with any cheaper system and get more R-vaule and quieter roofs. It's possible, Just keep adding the parts and pieces together and eventually it be higher and lower. But for how long?

ICF has only 3 main structural components, concrete,steel and foam. The expansion and contraction is similar with all componets in TICFS, making them a much stronger and longer lasting structure than buildings built out of many dissimilar components, such as lower cost structures.

The question is "can we Make a Roof with Concrete?"

The answer is "We MUST make the roof Concrete."

I have a ICF house and Wood Roof.
Money and care for the roof that I spent is incredible.

Ignoring the surface coating that both types of roofs require, my wood roof has been cost effective and maintenance free.

On a lower slope roof, I'd use concrete/shotcrete over foam (like Insul-Deck) vs concrete inside foam (like an ICF).

Posted By ICF372 on 17 Sep 2013 11:15 AM

The house in the video is in Ireland. Our prototype is in Michigan and had a 5.5/12 pitch with a small turret.

The cost will be $20 and up.

I am all for concrete/ICF due to many reasons, one of which is long term sustainability.

Usually products like InsulDeck are used for roofing applications although standard ICF wall blocks can also be used, not as common though.

An ICF wall runs on average around $13-$15 per wall ft². The concrete roof at $20+ per ft² is a harder pill to swallow but if one is looking for a stormproof shelter, that is the solution. From what I have seen, the cost is usually $23-$27 out-the-door per ft² for the roof area.

As far as R-Value goes. A concrete roof would not be the best solution for that. The 2012 IRC requires R-49 for roofs in Zones 4+. That would require 12"+ of EPS foam.

Someday they will make hollow cored foam panels (like Insul-Deck) or ICF blocks (still leaving a cavity for concrete) that are partially filled with cellulose for a more cost effective R value. Or maybe a complete ICF block could be made from cellulose and glue.

How would you do large eaves (aka overhangs)?

http://www.eplans.com/house-plans/epl/styles/craftsman-house-plans-and-homes/prairie/hwepl00896.html

is an example. 

The principal requirement would be tornado resistance, thus a concrete roof ... but want the eave along with it.

You can attach 2”x 4” directly on top of the ICF and overhanging as required. This will also create a vented air space.

Cost for a ICF roof is higher as stated early in this post. However the added security is worth it. It will keep your family safe during storms or fires, whereas insurance only pays bills after the fact.

A funny thing about cost, here in Michigan boat owners pay $10.00 per sq. ft. to shrink wrap and store their boats over the winter and they repay that every year. That's n roughly the cost of a simple ICF wall....

$10.00 per sq. ft. to shrink wrap and store

I've heard of $10 per linear foot to shrink wrap but never a sq foot cost.

Those are some large overhangs. They would require a shore and pour with internal concrete beams if concrete.
If the house was mine I would us Wood post an Beam for the porch areas and reduce the overhangs 16" or 2'.

Overhangs and porch's I feel don't need to be as strong as far safty during storms.

Thanks, Eldon.

What is 'shore and pour'? I can guess, but explanation??

Would extending the joists with LiteDeck/Insuldeck/QuadDeck constitute 'internal concrete beams'?

A agree that the porch roof isn't as critical as the roof over the enclosed part of the house. But single slab strikes me as attractive.

Shoring is Temporary bracing"shoring" that is used to support the concrete during curing process. Placement of concrete or "pouring" is on top of shoring.

Lite-deck ETC. will need shoring and Shoring is Temporary bracing"shoring" that is used to support the concrete during curing process. Placement of concrete or "pouring" is on top of shoring.

Lite-deck ETC. will need shoring and post and beam support on the outer perimeter of overhangs