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ICF for simple garage foundation?

Gene_Davis's picture

We are in deep frost country, and put tops of footings at a minimum of 48" below grade.


For an unheated garage, the typical foundation is a poured concrete wall arrangement, 48" high 8" thick walls atop 16" w x 8" h spread footings, then a 4" slab inside.


To control our cost and schedule, given the extreme unreliability of the concrete foundation contractors hereabouts, we are considering doing garage foundations using thin (meaning smallest cavity they have) ICF systems.


Have you done this?  Does it make any sense for you?


Using a rule-of-thumb cost for poured concrete work at $275 per c.y., a 24 x 28 foundation (just the wall part) costs us about $2,800.


The walls would have an area of 416 sf, and the concrete pour inside would be about 7.5 c.y., for a cost of about $700 in crete.  I see it as needing the ICFs, steel, and labor to erect coming in at less than $2100 to make sense financially.

 

"A stripe is just as real as a dadgummed flower."

Gene Davis        1920-1985

(post #75200, reply #1 of 7)

Okay, first let me say that I have zero experience with ICFs, I think they're an interesting concept and I'd like to work with them at some point.
But I think, barring extreme costs, that you've answered your own question.....

"We are in deep frost country..."
"...given the extreme unreliability of the concrete foundation contractors hereabouts..."

Seems like the scheduling alone would encourage their use, but to me, the additional potential costs of heating, blankets, etc. would make me wonder why to use anything else. Assuming that you're placing this concrete any time soon.

(post #75200, reply #2 of 7)

The job will be done in warm weather.  It is a question strictly addressing the hassle factor . . . why call and wait for some clown when you can do it yourself?


But, what will it cost to be in control of one's own schedule.

 

"A stripe is just as real as a dadgummed flower."

Gene Davis        1920-1985

(post #75200, reply #3 of 7)

Gene - your cost will vary according to what you pay for the ICFs - mine was high due to shipping.  They are fast & great for stem walls etc.  We did a 900 s.f. addition stacking and pouring the block the same day (me & 3 kids)  We poured the wall and the footer at the same time - using expendable PT 1x2's (or were they 2x2's) screwed across the footer forms.  We filled the footers the first pass, and 32" of wall the second pass.  Less than 1 hour concrete time.


Use form-a-drain and you can leave the footer forms in the ground too, if speed is the object.


Steel stud track fits nicely on the top of the foam to straighten things up, and 2x4's for bracing.  After your first pour, the rest will be cake.


16 yards of concrete from a trailer pump and we were done by 1:00.


 


Treat every person you meet like you will know them the rest of your life - you just might!
Treat every person you meet like you will know them the rest of your life - you just might!

(post #75200, reply #4 of 7)

Gene Davis.


 Yes do so! I built with ICF's and it was really simple and straight forward. In fact I wrenched my back shortly after I started, (Nothing to do with the work) and had my sister-in-law finish it for me.. she'd never done anything like it and I explained the process to her and she went ahead and did most of the rest of it in a few hours..


 Her only quaification was she was willing to attempt to do it.. Other then that she'd painted a few walls and put wallpaper up twice. period!


  With my back out of commision I didn't check untill the next day when I finished up what she hadn't gotten to.  When the pump truck came I had a neighborhood kid run the hose (he'd never done anything like this before either) and a few hours later it was all done.. piece of cake!


  

(post #75200, reply #5 of 7)

ICFs for less than normal concrete walls?  Sign me up.


I'll take a stab at our costs for such a project.  Roughly 20'x20'?  That's roughly 22 ARXX blocks per row so you're looking at 66 blocks @ $20 each for $1,320.  With so little left over I'd say you would barely cover the labor costs let alone footers, concrete, rebar and such.


In your climate instead of going to 4' you could use a shallow frost protected foundation with 2' walls so now we're only talking about two rows of block, but extra money would be spent on foam.


Good foundationing


 


 


Beer was created so carpenters wouldn't rule the world.

 

Beer was created so carpenters wouldn't rule the world.

(post #75200, reply #6 of 7)

i've been involved with icfs before. first i don't think your going to save much money,that being the only negative i can think about.postives: once you pour the footings setting up 3 rows of block will go really easy,you will have a insulated foundation that will help keep the floor warmer,you will be able to control your scheldue which is a big thing for me. if i was to do a wall like this i would use the icf's but here in kansas we usally just do a mono pour on small garage,you waste a little cement but 1 pour and footing,foundation, and floor are all done in a couple hours.have fun

hand me the chainsaw, i need to trim the casing just a hair.

the older i get ,

the more people tick me off

(post #75200, reply #7 of 7)

It gets pretty darned cold in Manitoba, yet they'd permit you to build an unattached unheated garage on a thickened perimeter slab- no footings. That's the cheapest option.  Obviously no good for an attached garage.


Given that you need foundations and stem walls, ICFs are easy to work with and take little labour for a job like this.  Base your costs on actual firm quotes from people who would do a CMU foundation for you and I'd be surprised if it wouldn't be worth your while to do this yourself with ICFs.  I did piers and grade beams for my own garage to protect a nearby tree, and the ICFs were cheaper than the materials to build single-use forms would have been- forget about the labour to build the single-use forms.  I suspect you'll get pretty good pay for your effort versus hiring the job out.  Plus it will give you a stronger foundation when you're done than you'd get out of concrete block.


You can probably pour such a short wall directly from the concrete truck, without a pump, if you use a means to slow down the 'crete so it doesn't blow out the forms.  A pump makes it pretty idiot-resistant.