Patio sub base

[daveaspy]

I inherited this as part of a house move, it did have a shed on it which unsurprisingly had a rather uneven floor
The whole area is 3.6m X 4m and is very solid apart from this end

The fence posts are very solid with a couple of concrete gravel boards at the bottom, and these are on top of a high retaining wall going down to the next garden below (to the left in the picture).

Not really sure what's gone on with that last row or flags but there isn't much underneath them except lots of crumbly sandy material. I'm going to get someone in to sort it (maybe replacing them all with something prettier) but wanted an idea of what they should be doing before they just suggest filling it with more sand!

I'm thinking some proper hardcore should go down first, but can that go right up to the gravel boards and be whacked down without the gravel boards breaking?

 

[conny]

If you are going to replace the flags then it is probably wise to remove the present ones and re-do the whole sub base, laying down and whacking some more hardcore.
Otherwise, removing the tilted slabs and re-doing that left hand section, (again with hardcore and sand), would be the cheaper option.
You can certainly whack upto the edge of the gravel boards without damaging them so long as you don't go pushing the whacker against the face of them.

 

[daveaspy]

Cheers. Would be nice if I could get away with just sorting out the last row but I know my other half has eyes on something more Mediterranean

 

[daveaspy]

okay - so I pulled down the remaining side of the shed this morning and discovered a rather large problem that caused the upheaval of the flags

I thought this tree was in the neighbours garden, but it seems to have grown from my side of the small wall. Seems a very big trunk if its just squeezed between some flags and a stone wall though!?

I don't think there is any option but to get this removed, presumably from well under the patio surface too