Grunff wrote:
Lobster wrote:

I'm about to start laying a new small section of solid floor (approx
1m x 1.7m) - first time I've ever done this. Think I've extracted
from the uk.d-i-y archives all I need to know, but could someone
explain about requirement for compacting hardcore prior to laying the
concrete? I have excavated about to about 15" below the final surface
(it's earth now), and was going to chuck in 6" hardcore now. Am I
supposed to sort of jump up and down on the hardcore a bit before I
blind it with sand?!



Ideally you need a wacker to compact it. They are quite good fun to use.
Having said that, this is a very small section of floor, and I suspect a
good bit of jumping up and down might be enough.

The reason for doing this is that if you don't compact it sufficiently,
there's a chance of future settlement, which could cause your 1x1.7m
slab to move relative to its surroundings.

I have a similar question to the OP

I want to put an 8 by 12 foot shed on an old greenhouse base. I intend
throwing all the various bricks and rubble in the middle and topping it
off with hard core.

Without tamping it down, will I have any serious settlement problems?

Dave