Self-binding gravel on rock - How to lay self-binding gravel on solid

[Jezza66]

We have a fairly steep sloping yard made up primarily of a solid rock (slate) base. It's seriously uneven in places causing it to catch car undersides. To even it out we are thinking that self-binding gravel/slate may be an option. But are concerned about adhesion and being washed away with water getting beneath the gravel and effectively lifting the gravel (esp when frozen). equally same concern if we lay a screed base. Any and all suggestions gratefully received.

[r896neo]

Your concerns are valid but unavoidable with out going for a bound surface of some sort like concrete or bitmac.

To be honest well compacted self binding gravel will form a relatively impervious layer which water will simply run over the surface of.

Your main problem will be if you have large volume of run-off from land up the hill from you. If there are any rills or channels which already flow down the area from above then they will as you say wash channels into it.

Simple rainfall will not do this so siting of drainage or at least diversion of exisitng water runs would be needed.

That said come the annual semi-floods we get now they will wash large channels in it if you get run off from above you leaving a clear up and re-leveling every time.

If however there is no run off from above it may be more do-able.

[simeonronacrete]

If the base is stable and strong (like concrete) you can:

lay a bonded screed to smooth out the lumps and bumps (minimum depth 6mm, up to 50mm in a single layer)

then overlay with a resin bound aggregate decorative driveway finish

Have a look at:

Ronafix screed
RonaDeck Resin Bound Driveway

[Carberry]

If the base is stable and strong (like concrete) you can:

lay a bonded screed to smooth out the lumps and bumps (minimum depth 6mm, up to 50mm in a single layer)

then overlay with a resin bound aggregate decorative driveway finish

Have a look at:

Ronafix screed
RonaDeck Resin Bound Driveway

If parts of it are scraping the underside of the car I would say it's a lot deeper than 50mm.

[simeonronacrete]

If that's true then some breaking out will be needed to remove the high spots.

[Jezza66]

Really good feedback from all - thanks. But you're right Carberry the differences are greater than 50mm. The challenge with breaking out is that the drive gradient is then to the lowest point (which is pretty steep). I don't know much (anything) about this but could we set concrete in the bowl areas and then apply a bonded screed on this in order to level it out?