Engineering the slab.

This project started out with some research. There are plenty of information sources on the internet to describe how to pave with concrete. All saying different things. The consensus with usergroups was to use a crushed rock bed especially if the soil is subject to movement (eg high in clay) this will allow the soil to move under the slab without stressing it as the crushed rock stones will shear past each other. Unlike most construction, there are no regulations covering concrete pavements and there is a lot of conflicting information out there. I got myself a copy of AS3727 Guide to residential pavements. Surprising this standard doesn't recomend crushed rock beds for pavements, but they seem like a good idea.

This is what I came up with for my slab.

1. Excavate approx 50mm of soil from the site (any deeper would be hard work).

2. Construct formwork with 150mm wide treated pine planks.

3. Distrubute a 75mm crushed rock bed.

4. Put F62 reinforcement mesh at the centre of the concrete area.

5. Pour 100mm of 25Mpa concrete.