I'm looking at slabbing an area of my garden and then sticking a cabin on top.

I have a large amount of old slabs and some other rubble/hardcore. If i smash up all the old slabs, will this be a suitable sub base for the slabs?


  • Do people do that? Yes. Does it make for a good, stable, and long-lasting base for a slab? In my experience, no, it does not. Your mileage may vary, however. – jwh20 Apr 8 '20 at 17:23
  • "Slabs" ? What are your slabs ? How will they be installed on the rubble/hardcore ? How would they be secured as to not move if there was and earthquake or ? ? More info is needed. – Alaska Man Apr 8 '20 at 18:35
  • Thanks for the replies. The slabs are medium size and would be broken/crushed up into small rubble. At least that was my plan – Ed Jones Apr 8 '20 at 18:39
  • Your question reads like you are saying you want to install existing slabs on rubble made from broken up slabs. "will this be a suitable sub base for the slabs?" Clarification is needed. – Alaska Man Apr 8 '20 at 21:48
  • Sorry, I have old slabs and new slabs. I wanted to break up my old slabs and use them as a base for my new slabs! – Ed Jones Apr 9 '20 at 16:58

The best base has a range of aggregate sizes so that they all fit together, lock in place and fill all the voids tight. Therefore the answer is dependent on the size of the pieces you break the old slab into. The smaller, and closer in size to the rest of the fill is best. Or have adequate space between larger pieces so that you can be sure to fill all the voids very tight or over time the soil and other aggregate will migrate to the voids and settlement will occur.

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