I'm a student majoring in Concrete Industrial Management, and I am doing a project involving ICF subcontracting. During the course of this, I have ran into a few questions. Some of the biggest ones are related to the budget, but I also have a few general ones.

1. Is there a sealant that must be sprayed on ICF blocks, to fireproof the Styrofoam? If so, is this done by a subcontractor or by the ICF contractor and what would be a general cost for this?

2. Do forms have to be used at all, to construct ICF? I realize the block is considered a form, but I am just covering all my bases.

3. What are scarf planks?

4. Are rebar, concrete, and block all the materials used?

Thats all the stuff I can think of off the top of my head. Any help is greatly appreciated.

-Zach

Zach,
Go to the website of any of the better ICFs. download their construction manuals,
and read it. You'll find answers to many of your questions, and probably more questions to be answered. But you will have a better idea about the questions you should be asking.

Zach

I agree, look at individual websites.  We just built a 3400 sq ft home ICF we used Nudura.   One thing is a grey area.  IN our  county it is not code to put drywall over the ICF in the basement.  Other counties it is a code, you might want to investigate that a little more

Scarf Planks? Never heard that one, Google only had a few hits too, most of it was boat related. The only concrete reference I found was concrete forms for constructing a bin.

So what is a scarf plank?

I think I quoted a typo, when I put scarf planks. I believe the individual was referring to scaffolding planks, now that I think about it. Haha. I went and reviewed Green Blocks technical manuals, and noticed they mentioned scaffolding planks.

On average, how long would you say it takes to construct the ICF walls?

About the same length of time it takes to build CMU or wood framed walls.

I actually don't know typical times. How much time and how large of a crew would be required for a 3,000 sq. foot house?

3000 sq.ft. house has many factors, wall height, number of corners, etc.

Figure out the sq.ft. of the wall and figure somewhere between .06 and 1.2 sq.ft. per man hour. it is all based on design, rebar calcs, etc.

Zach, your questions a way to vague to give you specific answers. You should read every manufacturers website info you can find.

Your a consumer, not a contractor who does this for a living.

With the exception of a shed or barn, you have more than 4 corners on your house.

How about a few windows, maybe a door or two, some service penetrations, bracing, scaffolding, bar fabrication, now lets add in meeting the people, calculating out the estimate/proposal, meeting again to sign the contract, ordering the materials, having everyone on site when the materials show up, unload the truck, do the 'what you saw as a day or so', arrange the inspection, arrange the pump truck and concrete, place the concrete and consolidate, come back and remove you scaffolding/bracing, load it out of the hole onto the trailer, clean up the job site and make it ready for the next trade.

Do you want to revisit that .06 to 1.2 sq.ft. per manhour?

So your sq per hour, is not simply for construction. That is the discrepancy. I was just wondering how long it takes to simply construct. Durisol bldg systems told me "a typical crew can stack and pour approx 200 blocks per day (600 sq ft of
wall area).' Thats what I needed to know, thanks anyways.

600 sq ft per 3 man crew works out to about $1.00 per sq,.ft at $20 per hour (installers cost without markup). This is a conservative number in my opinion. We charge between $2.00 - $3.00 per square foot for the labour component depending on the size and complexity for a typical residence. More complicated structures can be closer to $4.00 per square foot. That would inlcude the scaffolding costs.

Thanks for the info james. So the typical ICF installation price would fall in what range? Is $20 the average?

1. Most all ICFs are made with foam that is fire resistant. It will melt and not burn- no you will not need to fireproof.

2. A smaller project like the one you are describing would not need any extra forming. Usually the only time you need to bring in forms is if a section of the wall has concrete going from one face of the wall to the other (the concrete being as thick as the whole block). Depending on what block you use (some blocks are weaker than others) you will need to purchase lumber to support weak areas. You will need material to shore your openings.

4. Besides block, rebar, and concrete you will decide what materials you use for your openings, whether lumber, vinyl or steel. If you choose lumber you will need to waterproof the lumber if not treated.
Wire
Lots of screws
Fiber tape
Spray foam
metal stakes if the alignment system is over dirt
nails,screws or tapcons if over concrete or wood
something to anchor your opening material to concrete if using lumber
spray foam
maybe some duct tape

These latter items are smaller and not as costly, but they do add up and they will really cost you later if you don't have them and have to stop your production to get them. I probably left out a few items also.

On a personal note, I think this is a good project and wish i could have done something like it when i was in school. Learn as much as you can here. Having ICF knowledge is going to help you in the long run in your construction career.
Most guys that I know that get turned onto ICF never go back to conventional framing. I know i wouldn't want to.

Thanks Aaron! I am actually interested in starting a business utilizing ICFs. I have been interested in them for awhile, but have only recently started researching them heavily. Is it typical for subcontractors to do the exterior/interior finish?

An experienced crew can average 12 to 14 sq. ft. of walls per hour from start to finish.  That includes start up and take down, pumping, cleanup, and any rasping needed ti insure 1/4" + - in 10'. 
I thing that most of us would relish the opportunity to learn through early schooling opportunities.  Many of the early installer's are basically self thought, learning from the school of hard knocks. We braced with wood and pumped with line pumps. 
There are opportunities to work on training sites and get some first hand experience and get paid for your time..   

You can bring in other subs on an ICF project, although I know a lot of ICF guys who like to do the whole thing. One of the issues with bringing in other subs is that the ICF installer may need to walk the sub through their job; for example, the ICF contractor may need to spend time with the siding contractor to show him how to attach to the plastic.
I would rather use a screw because it will hold much better, but a siding contractor who is used to doing it quicker with a nail gun might not want to do it that way. Hopefully he would be able to figure it out himself, but if not, he at least needs to understand he has to use a ribbed nail at the minimum.

I would like to elaborate on Aaron's comment regarding fireproofing. By code (in my location), all polystyrene ICFs need to be covered for fire protection. Standard Drywall is acceptable. The issue is not necessarily burning, but it is an issue of flamespread and smoke developed. There are different fire characteristcs that come into play when a wall assembly is evaluated:

1. Fire resistance. This is the 4hour fire rating that ICFs have. This rating comes from the concrete core within the form. A sample wall is built and the wall asembly has fire on one side as they measure the temperature difference across the wall for time of the rating. After the test, the wall is loaded to failure and if structurally adequate, it passes the fire rating test for however long it was tested.
2. Surface Burning Characteristics. This is determined by what the form is made from. Polystyrene is not considered a Class A material and therefore the surface burning characteristics (flame spread and smoke developed) arnd even though the foam is fire resistant, the material still needs to be covered. Composite ICFs (Apex, Rastra, Durisol, etc) meet Class A requirements and have better (relatively speaking) surface burning characteristics (lower flame spread and smoke developed).
3. Noncombustibility. This is a specific test where a known amount of material is heated to a very high temperature (I don't remember the exact number) for a perioud of time. After the time has elapsed, the material is weighed and if it has lost more than 15% of it's weight it is considered combustible. There is also another criteria that can make it pass or fail, but I forget what it is. Either way all ICF materials fail this test and are considered combustible. However, the concrete within the form is the structural system and it is noncombustible. I beleive all codes allow for noncombustible structures (i.e the concrete walls) to employ combustible materials for insulation (i.e the form material). So All ICFs can be used in non-combustible construction.

We went through all this with a project recently....

Wow! You guys are very helpful. I have to present this project as a business startup, with all the financial information, to a group of concrete industry members. You don't even know how beneficial this information is. Right now I have my materials cost estimated to about $8/ft2 and my labor very close to $4/ft2, do those seem realistic? Also, I have my selling price somewhere between $18 and $19/ft2, do these seem accurate?