Directory Metric or Imperial

Concrete Block Gable Cutting Calculator - Cut and number all blocks before laying - Match off-cuts
This calculator was first created and used in 1988.

Angle Calc Angle
1st Height first height (H1) of first cut in rake - no bed joint. Alter this slightly to get more matches
Settings Colour

Gable Type

Calculate all the cut block dimensions in a raking wall, matching the off-cuts and positioning the bond beams ( if any ) for easy placement of vertical reinforcing steels (droppers). This system is very accurate and extremely fast, compared to the old 'stick and string' method. By slightly altering the height of the rake, you can optimize off-cut matching, often saving half your cutting. Enter length to apex, angle, corner / end type, bond and bond beam specifications to generate a cut sheet listing all the blocks in the rake.

The diagram above will display the selected end, corner, bond and bond beam settings.

Mark and cut the blocks first, numbering cut and off-cut. Then it's easy to lay the blocks up the rake by number.

The cut sizes are very accurate, so it's easy to keep the rake line straight without a string line. If you can't build the high end corner to the top of the rake, for the line, it's better not to use one. As ascending courses have less perp joints, the rake will center itself if you keep bond.

Just keep gauge and bond and you'll be amazed how straight and accurate the rake ends up. With 2 bond beam courses, the second course bond is staggered forward, so the core centres line up vertically, allowing easy placement of vertical reinforcing steels.

Repeating sets With a plain rake (not corner up) if you can alter the angle and starting height of your rake, you can optimize offcut matching, and use repeating sets of same size cuts, sometimes with just 1 cut size for the entire rake.

This makes marking and cutting much faster, because there are only a few different size cuts in the whole rake, and they repeat.

These are some angles and starting heights with matching sets. Select an entry to re-calculate the rake.

Repeating Sets

Circular Raking Walls with Arch or Bullseye You can combine this Gable Cutting System with the Circular Wall System to easily build curved or circular raking walls. Neither system requires a string line, so they combine easily. You can also use the Templateless Arch System to build arches or bulls-eyes in your circular raking wall. If you'd like more detailed info, please contact us ( ph: Australia +61 7 40987645 )

DON'T BREATH THE DUST If you're cutting 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

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All calculators on this site are geometric only.
Check relevant local regulations for appropriate sizes, spacings and all engineering requirements.

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↑ Remove This
Jack up
longLength of block no joint DiscardSmallDon't include blocks under this height
highHeight of block no joint Min Cut offDon't include blocks with less than this cut off
jointsize of joint   Match to the closest off-cut or the F away
Match+Accept matches up to this much higher Match -Accept matches up to this much lower
  Soft Metric 8" Reset 200 Close