Concrete or type 1 - What sub base

[barrj]

Hi - we are laying a new gravel driveway at a barn conversion (so no driveway before). The ground is very sandy and is on a slight slope. One contractor has suggested we need concrete as sub base as the DTp1 would move. Does this sound right? I am concerned the cost may rocket as a result but a t the same time we want a decent job.

Thanks for any help



:p

[ABILITY]

Would think mot base will be best, sandy soil is usually a good base to fill from if not to disturbed prior to stoneing up.
Can't see point in concrete base to support a gravel surface. Would end up with gravel skating about on the hard concrete surface.
Just ensure stone base is well compacted in layers if needed with a reasonable about of fines in it to bind together.
Should be aiming for around 30mm of gravel topping.
This is assuming slope is only gentle.

[Tony McC]

I'd go with Ability on this - a sandy sub-grade is often more suitable to pavement construction than is a clayey sub-grade (See the Table at the bottom of the Sub-grades page.

If there was any question about the suitability, my first consideration would be to use a geo-textile separation membrane rather than concrete. It's a fraction of the cost and probably more effective in a case such as this.