Concrete slab between trees

[Tris]

If you need to fix the sculpture in place through the gravel there are ground anchors available that are often used for kids swings and the like, 2ft long metal 'screws' that can be driven in with a Tommy bar and have a bolt fixing on top.

 

[Hlsmith]

Whacker plate for 1m x 2m!!!!!! Don't waste your money. You can tamp almost anything with a sledge hammer held vertically and pounded down on the end of the handle/ hammer head. Ten minutes work for 2 square metres. A whacker plate in these circumstances would be just silly.

Having said that, I wouldn't be casting a slab there at all. First you'll damage the trees, then next they'll damage your slab.

Whilst you can compact it like this it doesn't have the vibrations that reduce the friction between the material and cause the small particles to run into smaller holes and really bind it together
A sledge hammer head is also the wrong profile due to being slightly rounded it tends to push material out the side so always leaves a loose top layer a hand compactor does the job properly but for 2 square meters put in in layers and properly and thoroughly compacted by hand you it's not a ten minute job

 

[Chris152]

Are there any gravels I should avoid? It'll sit on a membrane to stop the gravel moving/ weeds coming through, but I don't want to put anything down that'll wash into the soil and hurt the roots. I was thinking of this:
https://www.wickes.co.uk/Tarmac-10mm-Gr ... g/p/131882 (says it's 'suitable for driveways, paths, borders and water features')
as it's cheap and will look fine. I've searched the net for info on gravel gardens/ pot topping, and not one specifies a need to avoid any types of gravel, so just checking.
Thanks.

 

[Hlsmith]

If you use bredon gravel of self binding gravel it won't move as much as pea shingle will

 

[Chris152]

!
The gravel needs more stamping then levelling, then just one more thing to complete!
Thanks for your help and suggestions everyone.