Creating stable foundations for garden room on a plateau

[sasl]

I'd like to build a medium sized (let's say 4x3 m) room at the top of my garden where there's currently the wreck of a shed. The area is at the top of a slope. There's also a drainage ditch for the adjacent farm field on the other side so the area sits on a sort of plateau. I guess this is potentially an issue for subsidence if I build a heavy structure on a concrete slab. Is a fairly thick concrete slab (atop compacted type 1 MOT) likely going to be ok for this location or should I be looking to stabilise it more - I don't know if e.g. piles are an option for a home project or maybe a retaining wall? Or a different type of foundation altogether perhaps?

Photos of the area attached. First shows highlighted in yellow the area I want to build the room, with the sloping garden up to it. Second shows a closer view and the third shows the boundary (highlighted in yellow) backing onto a drainage ditch.

 

[noseall]

I'd like to build a medium sized (let's say 4x3 m) room at the top of my garden where there's currently the wreck of a shed. The area is at the top of a slope. There's also a drainage ditch for the adjacent farm field on the other side so the area sits on a sort of plateau. I guess this is potentially an issue for subsidence if I build a heavy structure on a concrete slab. Is a fairly thick concrete slab (atop compacted type 1 MOT) likely going to be ok for this location or should I be looking to stabilise it more - I don't know if e.g. piles are an option for a home project or maybe a retaining wall? Or a different type of foundation altogether perhaps?

Photos of the area attached. First shows highlighted in yellow the area I want to build the room, with the sloping garden up to it. Second shows a closer view and the third shows the boundary (highlighted in yellow) backing onto a drainage ditch.

The only real issue I see, apart from the effort to get rid of the volume of vegetative matter, is the tree and its roots.

 

[mrrusty]

What sort of ground is it under the topsoil? As getting a digger in causes a lot of disruption and waste to clear, why not approach one of the ground screw contractors and see if ground screws are suitable for your ground? If they say it's suitable, its an easy and clean method for a garden room. I recently used easypads, but we have solid clay only 400mm under the topsoil.

 

[Dereekoo]

The only real issue I see, apart from the effort to get rid of the volume of vegetative matter, is the tree and its roots.

+1 What ever type of foundation you use the load will spread downwards at 45 degrees which will keep it well within the confines of the adjacent bank slope and the actual bearing pressure caused by the garden room will be at the low end of any allowable ground bearing capacity. Basically you are building another shed not a house