Pour foundation without forms

quarencia · Oct 11, 2015

Accidentally posted this in regional forum, but meant to post here, so I reposted. Anybody ever poured a foundation without forms? Not just the footing. The entire footing and wall without forms. Free pour directly in the trench. Getting ready to build small barn (20x24) for equipment storage and was thinking would be faster and cheaper to skip the forms. Have access to excavator with 12" bucket and can trench it myself. I remember a post years ago where tbn'r did this for a garage. Oh yeah, I'm in Connecticut, so I have to go 48" down. And I want to put slab inside after foundation poured. Anybody ever done this?

Jstpssng · Oct 11, 2015

I wouldn't try it if you have any frost in the ground; it will grab hold of any rough edges and move it around.

Deere Dude · Oct 11, 2015

Why not block? It's easy enough and fairly cheap.

KennyG · Oct 12, 2015

Doesn't sound like a good idea. The top of the slab should be 4 to 6 inches above grade. If you formed it with soil you would have to remove it.

turnkey4099 · Oct 12, 2015

quarencia said:
Accidentally posted this in regional forum, but meant to post here, so I reposted. Anybody ever poured a foundation without forms? Not just the footing. The entire footing and wall without forms. Free pour directly in the trench. Getting ready to build small barn (20x24) for equipment storage and was thinking would be faster and cheaper to skip the forms. Have access to excavator with 12" bucket and can trench it myself. I remember a post years ago where tbn'r did this for a garage. Oh yeah, I'm in Connecticut, so I have to go 48" down. And I want to put slab inside after foundation poured. Anybody ever done this?

The cost of the excess concrete you will need will exceed the cost of the forming by a factor of about 5.
Harry K

yelbike · Oct 12, 2015

Deere Dude said:
Why not block? It's easy enough and fairly cheap.

Are you talking about cider blocks or.icf blocks?

Ed of all trades · Oct 12, 2015

I am thinking of a small retaining wall and will just dry lay the block and pour full of crete. Ed

/pine · Oct 12, 2015

Actually the only reason for concrete forms is to hold/keep the concrete where you want it until it sets...and sometimes for suspending reinforcing bars etc...
If your excavation fills the bill...go for it...being less uniform it might require more material (as mentioned)...As long as you can address working and exposed surfaces it's a no brainer IMO...

Stimw · Oct 12, 2015

I just had slab put in for a 40' X 60' building and they only formed the top area.
They compacted the ground very well then dug it out per the drawing.

Deere Dude · Oct 12, 2015

yelbike said:
Are you talking about cider blocks or.icf blocks?

10" wide x 8"tall x 16"long blocks using mortar in between. I guess I never called them cinder blocks, just cement blocks... You would need footings the right depth for the frost problem and would need to fill holes in the blocks with concrete every 4 foot or so.

Funny story; I put footings in for a 1900 sg ft house with full basement and part of it was for a frost wall that was 4' deep. I was 27 years old and never really built anything major before. I got plywood for some 4' frost walls but didn't know how to hold them together so I formed it using 2x4s against the dirt walls and started pouring cement in. My wife did the mixing with a cement mixer using sand, gravel and portland cement. I would throw rocks in for filler. What started out as roughly a 10" wide wall 4' tall by 30' long ended up being 30' long, 4' high by 24 to 30" wide at the top. It started bulging out so I braced more and kept throwing concrete in with rocks maybe a foot in diameter as a filler. The upside was when I put cement blocks of and fascia stone on, I had a really nice base. That footing ain't goin' anywhere. That was 40 years ago.

In hindsight I should have used wall ties to hold them together or used cement blocks if I wanted to do it myself, or jusy used cement blocks from the frost footings all the way up.