icf construction without an “icf”
Is it economical/advisable to build a concrete home (foundation to rafters) with stay in place eps foam sheets attatched to temporary formwork, instead of using a manufactured icf? Anyone done this before and do you know the installed cost difference? What would be the best way to stucco (traditional) and stone veneer while minimizing sound bridges to the interior environ?
I am convinced the STC and R-values offered by this type of construction are ideal for my climate (Mid-Atlantic) and the extreme sound intrusion (200 ft from train tracks). However, ICF suppliers/builders are extremely limited in my locale and I’ve exhausted my search for a out-of-town ICF builder that will give me the time of day. A local concrete supplier/builder tells me he’s built a number of homes with sheets of the foam (owner chooses the thickness desired) in lieu of a manufactured icf. I’m considering taking him up on the offer (after inspecting his work of course), but he only does the site/foundation/concrete wall work and I anticipate issues with the stucco and stone application. What would need to be done to leave a happy workplace for the stucco/stone subs?
Replies
You would probably be better off to pour a traditional concrete wall and then attach insulation board.
The first difficulty I see, unless I'm missing something, is the hundreds of penetrations by snap ties after you've fought to align them through form panels AND foam board (without damaging it).
And you'll have to schedule the ties for the extra thickness of your formwork. A typical ICF panel is 2 1/4" per side, BTW.
There are tieless steel forms used in heavy construction, but they're not practical for residential work unless your project is on the scale of Bill Gate's house.
I don't understand what you're gaining. While ICF's are a bit more expensive per sq. ft. for the material, the labor is much less than traditional forming, little of the rebar needs to be tied and you have very little tear down.
Edited 7/11/2005 12:10 am ET by Notchman
There is an outfit that sells plastic ties to be used with sheets of 2" XPS foam. If you can't find it, I think I have a flyer from them in file still. Can look it up if you need. just reply to get my attention
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Another idea might be to look into a Superior Walls house. These are factory precast walls, built to your house's specs, then erected on site. You would be giving up some of the concrete thickness though, which would be less sound proof.
Re your current plan, why not put the foam on after the pour/forms are stripped? On the other hand, the train noise would still penetrate the windows in whatever type of house you build.
We do sprayed concrete walls against rigid sheet foam and it works fine, so I guess this too would work. But it seems an unnecessary complexity. There already exists a technology for doing similar. tridipanel.com is a flat panel of whatever insulation thickness you prefer, with welded wire reinforcing on each side. Shotcrete and you're done. No blowouts, as with icf's. Easier to run wiring. Better energy characteristics.
If the thought is intriguing, I know a crew that has built these and is set up for travel.
since we all seem to be on the path of offering a variety of suggestions...
frame standard exterior walls with 2x4 and plywood sheathing
frame secondary 2x4 walls on exterior walls only allowing at least 12" cavity depth
mesh face of interior walls
densely pack cellulose insulation in exterior walls to 12" thickness (or more, if you desire to make cavity larger)
advantages:
simplifies wiring, plumbing, drywall installation
higher R value than ICF
readily available subs to frame home
costs a lot less
you can do the cellulose yourself
straighter walls
a standard type of construction which saves immeasurable headaches, time and money
any exterior finish can easily be applied
disadvantages:
can't think of any
you'll have to do your own RTC comparison. my gut tells me that the numbers are going to be darn close
carpenter in transition
Maybe a standard concrete block wall, possibly fill all the cores, then apply foam sheets to the exterior and stucco that. Surely there are block masons in your area.
I'm sorry, I thought you wanted it done the right way.
I built an ICF house three years ago. We used a poured foundation with a 2 5/8" EPS foam interior, held in place with plastic ties like you said. The concrete pump guy I used was a rep for this system and he built his whole house, ground to eaves with this system, with foam on inside and out. The exterior foam is ready for an EIFS stucco, but the ties are also ready for furring, siding or brick/stone ties(you would need to leave a poured ledge). The ties on the inside are ready for drywall, like conventional ICF. He said it was half the cost of ICF. Course, he did it all himself! He told me the numbers at the time, but I don't remember. I don't think I can give you a specific brand name on here, but if you email me, I can give you some contacts.
I've been stick building for 25 years, that was the sturdiest house I've ever built!Would do another one, waiting for the right project.
Good luck, Kimball
I think you meant to reply to someone else. When you are typing your response, you can click on the "to:" name and a list of people will show. Those who have participated in the current discussion willm have an * by their name. I guess the other names are those who are logged on.
I'm sorry, I thought you wanted it done the right way.