Concrete base for paving slabs?

[Splamone]

Hi,

I am going to lay a big area of paving slabs in the garden, no vehicle use, and the ground is thick clay with pretty poor drainage. My builder has recommended laying a concrete base with a steel mesh to ensure it doesn’t move with the clay drying out in summer and swelling during wet periods. Is this a bad idea and maybe just the builder trying to suggest something he can do rather than using something like compacted MOT1? I’ll slope the paving away from the house.

Thanks

 

[Notch7]

If the ground is shrinkable clay what he is suggesting is probably correct, although there needs to be a drainage scheme, since water wont drain at all in clay.

Often builders recommend concrete bound base because of poor experience with unbound bases -due to poor construction, there is nothing wrong with an unbound base done correctly - in many situations, but perhaps not in heavy clay

 

[Splamone]

Thanks for the reply. I think the drainage will mainly be to the fence line and then to next door as we are above the neighbour that side! We’ve had concrete in the same area already and it didn’t seem to be a problem. We have a soakaway with an aco drain along the back of the house already in place so some drainage is available but a few heavy downpours and the soakaway is full as the thick clay doesn’t allow it to soak away very well! Best we can do I guess.

I’m not sure on the cost difference between concrete and granular aggregate but maybe it’s quicker to lay concrete which saves on labour?

 

[foxhole]

Used concrete on my back garden, was having it pumped into foundations so did garden at same time, Indian sandstone over the top, have clay soil but new soak-away copes ok.

IMG_3432

• foxhole
• 2 Dec 2018
• 1

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