New Training for the Fox Block Interlock

Foxblocks hero default

We have found it to be a waste of time and energy to attempt to offset or stagger the block as in the photo to the left. By creating a vertical stacked seam you will be more accurate with the job dimensions and will increase your profit by gaining efficiency with your crew[/caption]

Row One:

Simply start from each corner to a point within the wall. Cut one of the blocks to fit perfectly. The cut does NOT need to be on the cut lines. Measure the cut block and mark its measurement to the side of that block large enough for everyone to see.

Row Two:

Start from the corners again and when you reach the cut block on row one, cut the block above it to line up exactly. Again the cut does not need to be on the cut line. Measure the cut block and mark its measurement to the side of that block large enough for everyone to see.

Row Three:

(five, seven, nine, etc)

Should be exactly the same as row one.

Row Four:

(six, eight, ten, etc)

Should be exactly the same as row two.

Prior to Concrete:

Simply connect vertical seams together with strapping, or plywood, on both sides of each block. Use one 12” to 24” long strap, 3” to 6” wide, made out of 1 x wood boards or plywood sheathing attached with one screw in each tie on each side of seam.


We have found that the man hour rate will drop using this method because the crew spends less time thinking how they can get closer to the building dimension and more time actually being productive.

Building Multiple Levels with Different Sized Block:

All sizes of Fox Blocks ICF’s fit well on top of each other for any type of configuration with little or no modifications needed. This is simple math. Fox Blocks ICF’s are reversible with 2” projections and recesses which means you will work with a 4” offset. For this reason the 4”, 8” and 12” block all work well together as they are all divisible by 4”. Using the same math the 6” block attaches to all sizes of Fox Blocks with a 2” difference in tie alignment. This is not a concern as this joint line will usually happen at a floor diaphragm.

6" Corner block on Top of 8", 10" or 12" Block:

The 6” corner works well on top of the 8”, 10” or 12” corner blocks when going around an outside corner. For inside corners simply remove the projections off the corner block and continue building. You may need to create a stacked seam on one or both sides of the inside corner at which time we recommend you just move the stacked seams for each wall closer to that inside corner.