HELP!! Paving layers & concreat base paving urgent !

Hi everyone one,

I need urgent help as i have reason to believe that my builder’s work is questionable.

Plan is to lay paving slabs, which should be strong enough to withstand the weight of my car. However the car would not be parked there for long periods of time, it would be used only for washing or cleaning etc and maybe a few nights but no longer.

The builder has dug up the area up to soil level... then put concrete down. It was suggest this be 4 inch but in some places its more like 2 inches. We have trees nearby and when digging up the area saw many tree roots which we tried to clear out, however some big ones I would guess are still there or will grow underneath such is nature.

I don't think the concrete had dried out yet and it has started to crack up very easy, but my question is this.

With the above laid concrete and then say 2-3 inch screed and then 40mm paving.. is this going to last very long in view of the intended use.

What worries me is that the concrete has been laid straight on soil and no hardcore of type1 underneath. The soil was however compacted but I felt this did not achieve much. Compacting soil, I never heard of anyone dong that?

I would of thought that 75mm hardcore.. then compact down, then 150mm concrete then screed and then decorative paving to finish off. Would this not be stronger and be able to withstand tree roots. Previous we had 6ich concrete with 4in hardcore, and this never gave us any problem with roots.

Can someone more experiences be able to please advise me?

Is there an option to lay additional 2inch concrete on top of the work carried out so far? and if so would this adhere to the newly laid concrete ? Would it be better to break up the laid concrete (easy to do whilst still drying out) instead but this time put hardcore down then concrete?

Hope someone can me out

Thank you

Regards,
Stephen

Sounds like you already know what you need / want.
Though you don't need to concrete to lay slabs, just dig down properly, lay your type 1, compress then grit and slabs on top.
Concrete should never be laid directly onto soil, you'll end up with crazy paving.

your builders' methods are questionable, though it may be ok, provided he uses solid beds under the paving slabs.

was the substrate onto which he laid the concrete fertile soil (dark fertile matter) or was it sandy or gravelly looking?

if the trees are relatively close and the roots large then there is always a risk of damage, regardless of how diligent the builder is.

if he stated in his quote 100mm compacted hardcore plus 100mm concrete sub base then this is what you should get.

DIYStephen said:

Is there an option to lay additional 2inch concrete on top of the work carried out so far? and if so would this adhere to the newly laid concrete ? Would it be better to break up the laid concrete (easy to do whilst still drying out) instead but this time put hardcore down then concrete?

Click to expand...

yes, the concrete will be easier to remove whilst 'green'.

adding another layer will be ok as this is not the weathering course but do you have the height tolerance? this concrete sandwich will never be as strong as a single pour at twice the thickness.

Thanks every one for your reply


The concrete has been laid onto a kind of fertile soil and gravelly looking in parts.

I can have height tolerance as i would ask for more to be dug out to allow for increased height.

I get the impression from talking with others that it is better to lay concrete onto hardcore, however i could also put hardcore down then compact and then lay slabs etc to make it stronger.