The Brew Cabin

I have a major renovation project underway which is 80% complete on the main house structure (after nearly 3 years!). The house itself measures 20m x 9m so there is loads of external paving to be worked on in the near future.

I am currently removing some internal walls which is leaving me with a heck of a lot of bricks. Now I could put these in the skip (or skips!) but I was thinking that I could use this stuff as a base for my patios and paths.

I was thinking in terms of breaking the bricks up into half enders (sort of a hardcore) or smaller then compacting and throwing some concrete on top, before paving on top of that either with high end concrete flags or natural stone bedded into a 10/1 sand cement mix.

In this situation would you use the bricks or skip them and buy more suitable base materials?

The trouble with using owld bricks is that folk tend to chuck them in 'as is' and then, when the rest of the fill and the bedding starts to settle, and then what is called the ‘reflection’ of the bricks starts to show through, and so you find that, f’rinstance, bitmac follows the ups and downs of the bricks and flags start to ‘rock’ on the high points.

Here’s a pick of what I mean about folk using full bricks as a sub-base….



…it’s a big NO-NO!! :(

Even breaking them in half isn’t ideal. Although this does tend to reduce the incidence of reflection, it doesn’t get rid of it altogether. What you need to do is break them up into quarters or smaller – the smaller the better – and then ‘blind’ them with grit sand, rock fines or crushed stone, so that all the voids between the smashed bricks are filled, and then compact the lot, repeatedly running the vib plate or roller over the area until all the ‘fines’ are rattled into the voids and you have a reasonable ‘capping layer’.

You can then regulate the top of this layer with 75mm or more of quality sub-base material – a DTp1 or a crusher-run material. You could use your lean-mix concrete, but there’s no burning need if you’re going to use a decent thickness of bedding/base for the flags.

If this were mine, I’d use the smashed-brick with added fines to form a sub-base or capping layer, and then when it came to laying the flags, bed them on a cement-bound material. If this were a driveway, then you need to use a C10 or stronger concrete that’s at least 75mm thick, but, for non-vehicular paths and patios, the 10:1 bedding mix will be fine, and it only needs to be 50mm thick at most.

Tony,
Thanks for the valuable advice.

cheers

Martin Lloyd