The Brew Cabin

Hi Tony
When laying a sub base of scalpings 100mm thick how much will it compact under several runs of a 'wacker'. Your 'excellent' calculators tell you, you need x tons at 100mm compacted but how thick should you rake it to prior to compaction.
In my case the scalpings are laid ontop of compacted brick rubble
Thanks

There's no set figure - you can't say that 150mm of 'sub-base material' will always compact to 100mm thick, as the moisture content, type of stone (or other material), size/weight/efficiency of compaction equipment, all have an effect on compaction, but, very generally speaking, 130-150mm will compact down to 100mm.

HTH