Two years after the fact I'm still not sure if I came out ahead or not serving as my own GC on my DIY ICF house. I had a builder working with me. Had to in order to get any money from the bank. He let me use his account at a local lumber yard so in that respect it didn't cost me extra being my own GC. He had me me use his usual concrete, roofing, and drywall guys, who all did a good job for me. Again, I probably came out even on the cost of those services. The concrete guy charged me for his time plus the actual cost of the concrete. He also let me use his account to buy miscellaneous concrete supplies, rebar etc., at a concrete supply house. The roofer supplied only labor. I provided the material. Major items I bought myself directly were trusses, windows, and roofing. The trusses came from a local truss builder who bid the job at a better price than another truss builder. The windows and roofing I bought from big orange, with the windows coming in less than the local lumber yard my builder had the account with. Asphalt roof shingle prices were pretty uniform around the area, so I got as good a price as the roofer would have gotten. Drywall was another matter. I couldn't buy the sheet rock myself at as good a price as the drywall contractor did. He subbed the hanging to a south-of-the-border gang he regularly used. They were fast. Rocked my entire 2000 sf house in one long day. I was, however, not 100% happy with their work. And I'm not sure that in this case I might not have gotten by for less if I had put the job out for bid among two or three local contractors. My builder partner had his regular subs and I'm not sure they were always the best.

I did much of the work myself, along with one of my builder's employees, Tom, who worked with me full time. He was a God send. He knew the ins and outs of a lot of the interior carpentry that I did not know and kept me on the right track. I did all my own plumbing and electrical. Tom was a stickler for doing things right, like I am, so we got along quite well. He also was a fast learner and we learned together the ins and outs of ICF. My ICF supplier provided some hands on training and supervision so we weren't groping in the dark in that area. Tom and I did a d*** good job, and therefore not a fast, or half fast, job. That hurt me, cost wise. The builder and I both did tile work. He gave me his thumbs up on how well I did, but in retrospect I'm not sure either one of us did as good as a really good competent tile man would have. I believe we did better than a run-of-the-mill slam-bam tile man would have done, but it cost more too.

pura vida, you mention how long it's taking just doing the planning. I did my own design, and construction drawings, using TurboCad. It took one full year from the time I bought the lot to when I had the plans finished and ready to start construction. Then it took 14 months to build the house, and that was having the builder do the roof construction and install the siding. The builder got two things out of the project, a fee for guidance and use of his accounts, and a steady job and income for about 4 months at the end of the project because the bank was on me to get finished.

Did I come out ahead serving as my own GC and doing much of the work myself? Yes, and no. Time wise, most likely not. Money wise, maybe. Where I spent more than I will probably recover, aside from the loss due to the market collapse, is in the quality of the construction. My builder and I were discussing a house being built across the street at the same time. He said in ten years that house will need work to fix up cracks in sheet rock, replace shoddy cabinet installations, repair cracks in the tile work in the kitchen and bath, and so on. My house, he said, will look as good in ten years as it did the day we moved in. Tom and I put in a lot of time doing quality of work that isn't visible. What I don't have is a lot of "artistic" prettiness that an experienced builder and/or architect would know is the current fad.

I really like my house. It's comfortable to live in. I just wish it hadn't cost me so much to build it.

Time is the thing DIYers need to account for.  I think a good amount of them THINK they can do it, and then about half way through realize they just can not, whether its time, working at night and on weekends, the skill level, etc.  Some screw things up so bad, it costs more to pay someone to fix it then what it would have cost them to begin with. Building is not hard.  Proper building, however is.  I am DIYing 100%, with exception of thing code will not allow me to do (such as plumbing drains and electrical and HVAC equipment).  But I have also worked on a construction screw for a few years during college years, and am finishing up a 1600 sqft addition onto my parents house right now.  If you know what you are doing, and DO NOT underestimate the time it takes, then it can be a big money saver. However those are 2 very important points in the success of your project.

Back on ICF vs....for MATERAILS only, my ICF quotes are about 5800 for Hobbs block and they say I need around 22yds of concrete, so about $2200 there. Another $500 in rebar and other items needed for the job, works out to be about 8500 for a house with 1764 sqft of wall. (main level only)  Basement walls are about $10,000, but they are 10'-4 to account for floor structure and slab.

However for our area (north east Iowa) I am really thinking ICf is not really the best option above grade. It would appear that it can start to work against me in our winters compared to a r-30+ wall assembly that costs less then half that total for materials.

Irerarc, Just curious how you would build an r-30+ wall assembly. Obviously, it can be done easily enough but most people out there think that if they have r30 in the cavity they have an r-30 assembly. It might be close to r-30 or it might be close to r-5 depending on how it's put together. Regards.

my assembly is staggered 2x4 framing, on 2'-0 centers on 2x8 plates. So for plate bearing, this actually puts a stud at every 12", gives me a complete thremal break (with exception of at the plates) and a 7.25" void to fill.  1.5" XPS exterior insulation (r7.5) and blown fiberglass insulation (r4.2), so basically about an r-37, insulation value only.  However I am debating eliminating the exterior XPS, and using ZIP sheathing instead which will save some cost, although not much if I use ZIP vs osb, but also it makes details and siding attachment a lot easier. Or maybe sheathing the entire thing and doing only .5-1" XPS or EPS. I am finding it does not really affect my heating load either way. A 3 ton geo unit will cover either option.

r-30ish was about what I was shooting for, total stack up, so I am right with you. All heat loads/gains are based on r30 walls.

however would you agree with my assessment that ICF is not really that great of a solution, (when compared to something like this of course), for colder climates?
DIY makes labor free, and material stack up is about 3200 for the exterior walls and sheathing. This excludes insulation. Insulation, if I pay someone, adds about 3k to that price.

Labor is never free. When you do it yourself, you pay an opportunity cost that can far exceed the dollars that you will pay a competent contractor.

you imply DIYers have 0 construction skills or competence.  How is the labor cost change if said DIYer was a contractor?....
I do not diagree with that, I have fixed plenty of DIY attempts. But its not always an accurate blanket.

however would you agree with my assessment that ICF is not really that great of a solution, (when compared to something like this of course), for colder climates?

Izerarc,
I do support your DIY attitude and your double wall (DW) design is pretty cool.  However, I can't agree with your assessment about the ICF.   The colder climate doesn't really make much of any difference -- in fact ICF is still far more prevalent in the colder areas.   We could have a blog about that alone.

Your DW solution is going to be less expensive than your typical ICF.  However, folks are given similar decisions to make when they buy a car.  Cheaper better etc.  DW will be perhaps 1/4 as strong as a typical ICF.  It won't be extremely storm proof because you could throw a rebar through it like a spear.  It will have a higher STC than conventional but it won't be near 50+ like your typical ICF,  It will have virturally no fire rating at all compared to 3 to 4 hours for your typical ICF.  It will likely outlast us both won't have the lifespan of the ICF.  Finally, if the DW solution is able to eliminate virtually all air infiltration you will have a similar R-value.   Since you will have no thermal mass (according to ORNL) you will have to exceed it quite a bit to get the same thermal performance.   

Nonetheless, I do believe what you have proposed is far far superior to conventional construction I just can't agree that it's as good as ICF. Regards.

I do not mean to imply that DIYers have no construction skills. The opportunity cost is what you give up in order to build your own house. If you feel that your time is worth nothing, then your labor is free. If you give up overtime at your regular job to DIY, then your labor cost is the time and a half you gave up. If you're renting a house while you build your own, and it takes you twice as long to DIY than to hire a pro, add in all those extra months of months of rent payments. If you give up 10 months of weekends to DIY, your labor cost is all those lost weekends that you could have spent with your family. Like they say in the ads: Priceless. The opportunity cost can not always be measured in dollars.

i also agree that my labor is not free and will be the hardest "value/cost" to pin down when deciding to GC myself or hand the whole thing over to someone else. I am also looking at DW simply b/c i just don't think i will have the funds to build the entire house out of icf. not if i want to be living in it within the next 5 years i do like all the stated advantages of icf over wood framing but i question how much of the thermal mass comes into effect in cold or hot climates. thermal mass is advantageous when you have large swings in day to night temps but here in AK when it "normally" only fluctuates 10 degrees or so then the advantages of thermal mass start to diminish. obviously i am much more concerned with cold temperatures but the same would apply to extremely hot climates. summer time is mild enough that we don't have AC and the heater rarely runs may-sept ish.

we got our final house plans back so it is off to estimators... lets hope our eyes weren't bigger than our wallets!

dmaceld - thanks for the post and info. very informative and gives a great perspective.

Regarding thermal mass, icf's perform better when big temp. swing aren't present.
For example in ottawa region(r-performance 35ish) vs hawai region (r-performance 50ish).
There is thermal mass but the wall acts more as a buffer between in and out temps.
Hope I didn't open a can of worms, this was truly not my intention.

this was basically my point. for colder climates, is a higher built assembly better?

However, I know it involves temp swings. My climate has 100+ summers and negative winters. THe day swing may only be 5-20 degrees outside, depending however.

So what is really considered temp swings? Or is 70 inside, -10 outside considered the swing?

Izerarc, The daily swing you are referring to is the diurnal temperature change (resembles a sine wave). This is basically the high and the low for a given day. The larger the diurnal swing the better for ICF because of the thermal capacitance causes lag (delay) before the inside of the home realizes that a change has occurred. This delay results in a slower to act AC or heating system. The best time of year or ideal day for ICFs is when the diurnal swing is both above and below your inside desired temperature. Due to the lag your system may not come on at all on those days. For example if you lived in a hypothetical place where it was 100 at noon and 50 at midnight your A/C might not come on at all because the wall temperature would ocillate around or close to 75.

This most ideal scenario is not going to occur when it is very cold or very hot for an extended period of time of weeks or months. During those periods the value of the ICF is due to the delay. E.g. if its really cold (say 10) and it gets really cold one night (-20) the thermal capacitance of the walls will delay the impact on your house would cause your system to react slower and run less. Regards.

texasicf - much better example than what i had. thanks, best example i've read.

I've been reading with interest this thread and I'm still torn between ICF and stick built, besides the cost for the ICF being much higher in the Otawa area. What is the cost difference in heating a house for a period of 5 months? With temperature swings (diurnal) -10 to -20 (sometimes -40) degrees C for a period of 4 weeks? I do not understand the advantage of ICF, even with R22 on the outside the cost of maintaining the inside temperature I would have thought to be more expensive with ICF? The concrete will eventually cool off enough to create a cooler effect in the dwelling.

John

John, Here are some things to consider.
- if you're talking about a diurnal swing of sometimes (-10 to -40) C then a stickhouse would be generally overwhelmed. The ICF walls would store some of the heat that you would otherwise loose to the environment.
- How do you propose to get to R22 with a stick house -- and it's not quite as easily as your typical builder thinks.
- What is your temperature 2 feet or so below grade because your ICF walls will benefit a bit from thermal wicking from the earth.
- When you say create a cooler effect in the dwelling... a cooler effect than what a stick house?
- How do you propose to handle air infiltration with a stick house? How do you propose to handle air infiltration over time with a stick house?
I don't want to take the thread off track but air infiltration is going to be a huge issue for you in these climates. You might have a very high r-value and any air infiltration to speak of and you have nothing. Regards.

Thanks for the reply TexasICF

As to the OP and the LINK I also wonder about the ROI for the the ICF. From what I have gleaned it is all about air infiltration and it is not out of the question for an air tight stick built double wall with a clear R40. You just require a meticulous framer that is willing to go the extra mile.

I have been in my double wall passive solar, 3000 sq. ft. home for 23 years, I burn 2 tanks of oil for domestic hot water and heat, I use an air tight Dutchwest in the evenings for extra comfort in the darker days of winter. My new house is not condusive to the passive solar part so Iam trying to justify how the house will be built and the length of time I have left to enjoy. There is squite a difference in price!

The majority of the time I have to heat the house!

John

John, Different people choose ICF for different reasons. Several times stronger, Several times fire rating, higher STC, more energy efficient, desire thermal mass, bullet proof

I'm glad to see the double wall becoming more popular. Without the double wall one would need to go to 2x10 or 2x12 stud wall construction. Double wall spells out the conduction of the studs and causes people to wonder about how things have been built over the past many years. Double wall is a huge step up from conventional. Also, as you get serious about it it more closely resembles the cost of ICF. Forgive me but what is OP and LINK? Regards.

Pardon my cynicism, but based on my limited home building and remodeling experience, I'm not sure there's a 'meticulous' framer within 250 miles of my location that I would count on to frame my walls to the same level of air-tightness as an ICF home.