I am working with a client who is also the architect designing his new home. It is a large 3,500 sq. ft. home on the central coast of california. His original design included an exterior wall system comprised of architectural block to the exterior and stud framing right behind for insulation, wiring and plumbing. His specialty in his arch. practice is designing large commercial concrete structures hence his desire for the masonry appearance. This system needless to say is expensive and a budget breaker.
I have built a few ICF homes while working as a superintendent for another contractor, but was never in on the true costs of the ICF. Including labor, and the hassle factor cost of subs who are not working with ICF on a regular basis. I am familiar with the advantages of the energy efficiency, fire and termite proof. I have serious concerns about sustainability of ICF which I try to incorporate in my projects as much as the client will go along with. This seems to be a system that will incorporate concrete and give that thick wall look that the client is after, but what can I tell him to expect the increase in cost of say a 2×6 framed wall or even double framed, staggered studs 24″ o.c. on a 2×10 plate pumped full of recycled cellulose insulation.
I am trying to put together a “report” on the ad/disadvantages of both systems, cost being the major factor. Any information and/or comments to this end including links would be greatly appreciated.
Thanks,
Frank
Replies
I don't have info for you on the relative insulation values, but I'm sure that ICF manufacturers would R-value data on their websites, and I doubt it's in the range you'll get with 2x10 walls and blown-in, which is going to be in the high R-30s.
Definitely encourage him to look at the long term costs of heating his home, and try to emphasize that short-term savings may not be wise in the long run, given that fuel has nowhere to go but up. I would also look at the seismic value of ICF given the location.
Sorting out things like this is tough. People tend to look at the cost right now for construction, and not consider that in 20 years they'll still be living there and gas will cost 2, 3 or more times what it does now.
ICF will add about 4% to the cost of the job if your ICF crew knows what they are doing.
Subs will be another matter, be sure to find electricians & plumbers who are enrolled in the program so to speak.
Project management and site supervision is important because mistakes are cast in concrete.
Other than that, there are no drawbacks to ICF. Makes an amazing house.
I can do ICF's cheaper than stick framing. I guess if you need to train a plumber or electrician than it might slow things down but I find everything easier and faster with ICF's now that I've done a few.
There was a learning curve, but this old dog did learn some new tricks.
thanks for the info guys I'll post any other findings that I come across.
Sustainability calculations are one of those mathematics games that can lead to absurdly different conclusions based on small changes in assumptions. An ICF structure is very attractive in a sustainability calculation if you place a realistic life span number in the formula. Realistic for ICF would be in the 300 year plus range. This is hard to grasp in California where housing is perceived as a consumable, and is often built that way.
You also need to account for the energy savings for HVAC from an R24 and virtually zero infiltration. In addition, there is no material or energy (or money) lost over the life span to rot or termites. I understand there is only about one barrel of oil required for the EPS foam in a typical ICF or SIP house. ICFs will save more than that here on the Mendocino coast in the first November!
fxcullen,
ICF builders in my area tell me that the cost premium is 2% and confide that they could actually build cheaper than stick builders who attempt to build to similar insulational values..
We have used ICF's in the home we are building in Montana - in the moutains with forest behind us - 25 acres of fire potential. Can't say enough good things about it - it uses less fuel in the winter to heat (propane and wood) and stays amazingly cool in the summer where temperature can be over 100 degress for several weeks. We poured the panels ourselves with the help of friends. Had to use a concrete pumper - was more expensive but wanted to try this method of construction. Had no problems, no blowouts in walls, etc. Metal straps on forms act as studs - using cedar look hardy board for exterior - rock on bottom, topper with dark forest green roof. Drywall on inside attached to metal strips. Use heat tool to melt out groves for wiring and plumbing. It's going to be beautiful. Contractor that sold us ICF's came up for pour and it was really quite simple, just needed several bodies to tamp down the wet concrete and guide the pumper noozle. This contractor has a beautiful home in Whitefish that he built using his ICF product and hooked up to a program with Bonneville Power to moniter the power usage of his home. I can't remember the exact statistics he told us, but at the time (several years ago) it was impressive. Since we began, we've added another room ourselves using the ICF's, will concrete saw out the bottom of a window to enter the new livingroom (taking out window and replacing with french doors - also taking out back door and replacing with ICF and window to allow for roomier bathroom downstairs. It's like legos held together with foam.