Placing Concrete in the ICF Foundation
All hands on deck and a cool, cloudy day make for a successful foundation pour.
I gathered a few friends to help out with the pour. Though it only takes a couple people to handle the concrete pump discharge others are needed to vibrate the forms, keep an eye out for blow-outs, screed off the top and place the anchor bolts.
We made 3 passes with the concrete pump around the forms, each time bringing the concrete up about 1/3 the way up. Doing this avoids applying too much pressure inside the forms at once. And if there is a blow-out we can make a repair easier without fighting several feet of concrete above the break.
I don’t like watering down the concrete so we poured it as stiff as possible so rodding and vibrating are important steps to consolidate the mix as each pass is made. I used a 1×3 to jam into the second and third passes to mix with the layer below.
At the same time another worker followed a few feet behind vibrating the ICFs with an ICF Wallbrator (AKA Arkie Wall Banger) – a large plastic device that chucks onto a drill. The internal gearing provides low-impact vibration.
The pour went quick – less than 2 hours and we were onto the basement slab. With the pump already paid for a half-day we took advantage and had the operator spread the concrete between screed pipes reducing the amount of dragging we had to do.
About 38 yards of concrete placed and floated with 5 workers in about 3 1/2 hours. No blowouts and no rain to ruin the slab finish so all-in-all a good day.
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We are in the middle of a large project consisting of two buildings which are using ICF foundations. I am curious how you could have possible poured your slab on the same day that you poured your walls? Wall bracing within the foundation to prevent the walls from collapsing under the weight of the fresh concrete and to plumb and straighten the walls after they are poured is absolutely critical to the success of the project and those braces are secured with turn buckles anchored into the ground....so how did you pour a slab with them in place?
Reply to johscholl:
The photos you see with the braces on the inside are of the garage foundation. Beyond it is the main house foundation. We installed braces to the exterior on the house portion so there was nothing on the inside to interfere with pouring the basement slab.