We just recently poured our first ICF foundation using the TF vertical panel system. Everything went smoothly, except that the exterior corners of the foundation wall had a slight bow outward after we stripped the 2x6 corner braces. The bracing method used was what the manufacturer recommended. Since the foundation is subgrade, this won't be a problem, but how can this be avoided in the future when we pour above grade ICFs? Thanks.

Laneelmer,

Although I have not used the specific system that you used, I do have considerable experience with a host of different products. What I found is all systems have their own set of pluses and minuses. Then there are the advantages and disadvantages of the different types of systems (vertical, horizontal, premade block, panelized,...). Historically most system have had a problem in the corner when you vibrate near the corner. Many systems adopted using 1 1/2" nylon reenforced packing tape to hold the corner together to avoid seperation during concrete placement. This is very effective and may be an answer for you. If it is raining or cold where you are located, then put a coulple of 4" strips of 1/2 ply on the corner first and use plumer's tape or concrete form banding and screw the corner together strapping the corner back to the available web not associated with the corner piece. With some of the more evolved systems this is no longer an issue.

ICF Contractor

My guess is that the corner brace was only secured at the top and the bottom.

Next time add mid-point bracing or tie-backs to the wall, that should eliminate it bowing.

Also as mentioned, be careful vibrating too much too close to a corner!

Hi Lane,
Just a few thoughts on your corner issue. How tall was your wall, and what was the thickness of your wall? When the wall is over 9' tall an additional diagonal brace needs to be installed to keep the corner rock solid. Furthermore if the thickness of the wall is greater than 8" the corner post should be made with 2x8s or greater depending on the thickness. Another overlooked issue is the amount of screws used to build the corner post. They should be spaced about 1' apart with a firm attachment and no play. If there is play in the corner post there is a potential for deflection. Also make sure there are 2 screws at every connection. I hope this helps.