Hi, I’m new member and this is my first post. My wife and I are planning construction of our home next spring. We really like all the pros of the ICF construction but I’m on the budget. I’m trying to determine cost of DIY ICF 6” forms vs 2x6 stick with EPS on outside and inside cavity of the exterior wall. This does not include any openings. I need this so I can determine type of construction we will choose which will impact little final plan of the house. Here are my very rough estimates for just 1 floor, house will be 2 stories.

Perimeter 30ft + 38ft + 30ft + 38ft = 136ft ~140ft
Height - ICF = 9.25ft, Stick 2x6 = 10ft

ICF Wall
ICF forms - $5200.00 (7 ICF courses, 4 corners, not including rebar, no labor, no delivery, no hooks or bracing)
Concrete - $2500 (25 cubic yards of concrete)
Total Material - $7700

$7700 / 1295 sq ft = $5.95 per sqft

Stick Wall
2x6 – 165 x $8 = $1320
½ CDX – 45 x $20.00 = $900.00
EPS 250 R5 (exterior) – 86 x $12.00 = $1032.00
EPS 250 R10 (interior cavity) – 86 x $20 = 1720
Wall materials (no nails, no wrap paper, no delivery) = $4972.00
Framing Labor 1400 sq ft x $2.00 = $2800.00
Exterior EPS install Labor = $900.00
Total (material and labor) = $8672.00

$8672 / 1400 sq ft = $6.19 per sqft

So does this look right? Cost of DIY ICF will cost as much as hired 2x6? I would expect to see more savings on DIY ICF. Thank you, Jerry. BTW how do I format this post so is more readable? Didn't see any formatting options in the post form?

Cellulose + EPS is hard to beat.

You should be able to save a little and get better thermal and vapor performance by putting plywood only at the corners and adding an extra 1/2" of foam elsewhere. And/or use diagonal X steel straps.

I DIY'ed by ICF walls and they came in around $6.00/sq ft total cost including the ICF, concrete, rebar, pumper truck, DIY 2x4 bracing, and supplemental labor the day of the pour.

Arkie, thank you that validates my ICF estimate.
Does anyone knows how much it cost to frame 2x6 wall with outside sheeting per sq ft? With labor or no labor.

Posted By Jerry on 04 Sep 2014 08:07 PM
Arkie, thank you that validates my ICF estimate.
Does anyone knows how much it cost to frame 2x6 wall with outside sheeting per sq ft? With labor or no labor.

It's hard to calculate wood framing wall square footage costs. With ICF vs wood frame, it's not an apples to apples comparison.

With wood frame one would have to factor in the insulation, reinforcement, exterior air sealing, etc.

Even so, a 6" ICF reinforced core is a lot stronger than a double OSB sheared wood frame wall.

The price on ICF sounds kind of high, although by the time you add in delivery and re-bar, it makes more sense.

ICF is a premium construction method, and does cost significantly more than stick construction. Although a stick wall can be built to perform as well, or better than ICF, there are other advantages. ICF is much stronger and quieter. I also suspect that it is a more stable structure, meaning seams won't open up over time like wood houses that warp and rack over time. I chose ICF for the performance and because I'm one old man working alone, with no way to raise 2X6 walls. The entire house came out within 1/4" of plumb and square, and nominal dimensions. This makes the rest of the construction much easier by having really straight walls. Of course, you could build really crooked walls with ICF if your footing isn't perfect, and you don't adjust the bracing carefully.

jdebree, may I ask if you did full basement, how many stories and how long it took you to stock the walls?

We have a full basement. I went 7 courses of 8" Fox Blocks, then braced and filled the forms. I then built the floor deck before stacking the main floor, also 7 courses. Our basement is right at 8' ceiling; the main floor is about 9'5", because I used a double 2X for a top plate.

I don't really remember how long the stacking took. In the basement, I have two windows and a door. I cut holes on the inside of the forms for J-bolts to hang the ledgers. You're supposed to have contact with the concrete where the ledger bolts are, so I popped 5" holes with a hole saw, and the made plywood patches to keep the concrete in, and hold the J-bolts in place. It would have been easier to just use the actual ledgers for this. I will say this- the stacking goes quick, but you'll slow down on all the detail- ledger bolts, door and window bucks, bracing, various penetrations for electric and wiring, and re-bar. I used 8" Fox for the basement, and 6" for the main floor. The blocks aren't the same size, so I designed the outside dimensions to the 6" block, and had to cut the 8" blocks to fit. I rented bracing from my contractor, who I hired to fill the forms. It is important that this is done properly to consolidate the concrete. Another big time-eater was the way I did my window openings. I don't like the look of deep windows on the inside, so I designed a buck system to flare the inside window returns on a 45 degree angle. We LOVE the way it came out, but it was a lot of extra work.

I know some contractors just stack blank walls, and then cut the window openings. I'm sure it's a lot faster, but I'm cheap, and didn't want to waste all that block. I cut it very close on materials, to the extent I had to glue together a couple left over pieces to make a few forms. I drew all my walls in Sketch-up so I could carefully count the block and plan my cuts. There is also some planning required to make sure the fastening strips embedded in the forms will all line up. I did screw up one part of the basement before I learned. I drew a 'map' so I know where to put the drywall screws.

jd....can you post some pics of your windows, inside and outside?

Here's a couple pics. The inside isn't finished yet, so just raw drywall. There will be a piece of trim covering the gap between the sub-frame and the window. Basically, I made the opening 11" wider than the window, and built a subframe for the window, incorporating angled pieces of lumber. I sandwiched everything with foam as a thermal break. As I stacked each component, I used glue and long screws to tie everything to the actual window buck. Finally, I trimmed the interior layer of ICF foam to match the angle. I used 6" ICF forms, and the windows are a normal 4-9/16 for a 2X4 wall. The windows are flush with the outside, and trimmed in a simple Craftsman style.

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I can dig around and find a section drawing if you're interested.

The windows look nice. I wonder if it wouldn't be easier to make the window openings extra large and then use only triangular pieces of foam + glue to create the beveled shape and support the window. Then cover with plaster/stucco (like a SCIP).

I don't think just foam would be strong enough, at least for someone who lived in coastal FL for 30 years!

jdebree, those look nice.

I wonder why the decision always seems to be either innie or outie windows. Why couldn't they go right in the middle and be fastened with a wedge anchor into the concrete? No need for a buck then; one could just have a layer of foam between window frame and concrete.

FWIW, around here you can pay to have a conventional foundation poured, and then install foam, for less than DIY ICF

Last time I saw an analysis, it came to the same price conclusion. And EPS or EPS + studs/cellulose allowed better use of thermal mass than most ICFs or more insulation.

Dear Jerry

There are many ways to save money on building a house by DIY.
The ICF walls will be the most strong and energy efficient way you can build. NO way to compare with 2*6. there is a cost to build and a cost to live. If you plan to stay in that house for more than 2 years and even less the ICF is a superior way to build than traditional wood frame.
Also keep in mind walls are only 5-8% of the total cost of a house. ICF DIY will run  you about 2.5% higher cost to build on the total house project.You can hang  a 2$ light bulb or a $2000 chandelier on same 3 wire... that you can easy do walls are build one time and hard to replace. I have more than 20y of experience with this

Jdebree - how did you get your house plan for ICF? Did you have to find a specific house plan that supports ICF or were you able to get it changed to fit ICF's? I'm curious thanks!!

I designed the house myself, using dimensions that fit the product I used (Fox). One issue I ran into was that I used 8" blocks for the basement, and 6" for the main floor. With Fox, they won't line up on the outside, so I had to trim the 8" blocks so that the 6" blocks would line up.

It shouldn't be that hard to modify an existing plan for ICF. Bear in mind that the exterior walls are a lot thicker than conventional stick framing, so you will want to be careful of room sizes and window placements. I started with drawing the outside walls, and fitting the interior to it. If i were hiring an architect or draftsman, I would make sure that they were experienced with ICF. I spent a lot of time planning around the ICF. I have spent a lifetime designing complex molds and dies, so I have a better grasp than most folks on designing things that have to fit a certain way. Our house is a simple rectangle for a number of reasons, which made the design much easier than some of the designs popular today with dozens of jogs in the envelope and a dozen gables all over the roof. Make sure that all of the penetrations needed are accounted for, and then throw in a few extras. It's really hard to add a 3" hole through an existing ICF wall. With stick framing, the various subs can just pop a hole wherever they need one.

ICF is easy to cut, but you have to be mindful of the embedded fastening strips so that they line up. Otherwise, hanging outside and inside finishes would be a nightmare. I made an error in one part of my basement, so I will have to draw a diagram of where the strips are when I hang drywall. After that, I made drawings of each wall showing every individual block so I could keep things straight and minimize waste. I put the dimensions on every cut block, so I could pre-cut all of the blocks around a door or window opening without screwing up or wasting materials.

Jdebree - Sounds good. I'll have to look into that FOX product you mentioned. It's good to get my feet wet with what is out there. I've been viewing many house plans from various websites, but few plans are available for SIP/ICF or alternative methods. I'll take your advice and see if there's an experienced draftsman around town.

I imagine you learned a lot by building out this project. Definitely was no easy task. Congrats on that. Roof? What kind of roof did you use?

Posted By jonr on 04 Sep 2014 01:05 PM

You should be able to save a little and get better thermal and vapor performance by putting plywood only at the corners and adding an extra 1/2" of foam elsewhere. And/or use diagonal X steel straps.

I framed a lot of hosues using this same method of construction; plywood corners and foam everywhere else. This method was 'engineered' and met code. I doubt you could find one house now where the windows and doors closed properly due to wind loads racking the walls. With the exception of FRP plywood, this 'bracing' method is one of the worst things engineers introduced to residential construction.