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Calculate matching cut & off-cut sizes in concrete block walls with mitered corners - Halve your cutting!

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Concrete block miter cut diagram
Off-cut works 1/2 bond
Print and use the tables below to find optimal set out and cutting of mitered corners in concrete block walls.

Mouse over individual table entries (wall lengths) for a description of cuts, stretchers and fractions, to optimize cutting and off-cut re-use. Click entries to draw a bond diagram (below table)

Using these tables with correct cut sizes allows re using the offcuts (half bond next course).

Save half your cutting and eliminate waste.


Angle Series Type Setback
Stretcher Match
3/4 Match
Str 3/4 Match

Mouse over entries for description Mouse over entries for description - click for bond diagram.

Length 0 10 20 30 40 50 60 70 80 90

Click individual table entries to draw corresponding bond diagram.

For each Series (width) of Concrete Block, at any given miter cut angle, there is an optimal cut size, where the off-cut will fit next course, half bond. These sizes are marked in blue for stretcher cuts, and Green for 3/4 blocks. By cutting either a stretcher or 3/4, and using a 3/4 where necessary, you can often open or tighten bond to make all walls work with matching off-cuts.

For a wall that goes from a miter cut corner to another miter cut corner, find the entry for the wall length in the table above. Eg: for a wall 2720mm long, mitered corner to mitered corner, find 2700 in the left column and go across to the 20 (top row) to find 5 350. This entry is in blue, so exactly matches a Stretcher-Match. Start a Stretcher Match (cut 350 back to 240), then go 5 stretchers and the last cut is another Stretcher-Match. You've re-used all your off-cuts for Zero Waste, and HALVED YOUR CUTTING Match off-cuts and halve cutting

Always start with a Stretcher-Match, and try to find a length that suits a Stretcher-Match (blue) or a (green) ThreeQuarter-Match (a 3/4 cut instead of a stretcher) at the other end.

If the wall goes from a square end or corner to a Miter, select the 'Square to Angle' Radio Button. You can often open or tighten bond slightly to find a length that will match off-cuts both ends.

DON'T BREATH THE DUST If you're cutting blocks, concrete, stone or ANYTHING and there's DUST - DON'T TAKE THE RISK
Don't cut it, or cut it wet so there's NO DUST - Silicosis Sucks
And if you're cutting wet, wear a mask - there's dust in the spray too!

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