Concrete block sizes

[David WE Roberts]

Head being done in as usual.

I thought that building blocks should be normally twice as long as they are high. One book quotes concrete blocks at 450 * 225 which fits in with this.

However TP website gives block dimensions as 440 * 215 which does not quite fit this formula.

OTOH if you allow 10mm for mortar this does take the blocks up to 450 * 225.

So are all blocks 440 * 215 or does it depend on the manufacturer?

Is someone making cheaper blocks by trimming 10mm off the standard dimensions?

Cheers

Dave R

[dent]

The sizes of standard (440 x 215) blocks are cunningly coordinated to fit in with standard brick sizes (215 * 65). A block has a length equal to 2 bricks plus the mortar joint (215 + 215 + 10mm between them). A block has a height of 3 bricks and their mortar joints (65 *

3 + 2 * 10). A block has the same height as a brick stood on its end. A block put on its end is the same as 6 bricks piled up, including their joints. All these combinations (and others) mean that you can build walls with a mixture of bricks and blocks and don't end up having to cut lots of blocks or bricks to line things up.

As to your original question, some people sell them as `blocks for

225mm courses', meaning 215 block + 10mm joint, and others give their actual dimensions.

dan.

[David WE Roberts]

Thanks - very useful explanation :-)

[Andy Wade]

Also the 450 x 225 module size works out at almost exactly 10 blocks per m^2 - very convenient for estimating.

Some blocks are 600 x 225 though...