Sloping Garden / Excavated Garden Room

[freddiemercurystwin]

If the frame is designed to be used as a 'floor' then there'll be no problems getting it approved by building control and you not being sued when the next owner has a party on the roof and someone gets hurt.

 

[cdbe]

It's difficult to tell from the pictures, but if you have the space, I would consider a smaller retaining wall, part way down the slope - I believe that something up to 1.2m can be achieved with fairly limited engineering input. If you then left a small separation between the front of the wall and your new building for a suitable drainage system you could avoid any damp issues. Block and beam might be suitable for a roof/floor and could span the gap back to the original ground.
You need to be aware of any services - this sort of work often exposes gas, electric, water and drains. Sometimes you can work round them but otherwise they can be expensive to relocate.

 

[Notch7]

20k to dig a hole? Seriously??

I was gonna hire a digger and do it myself.

Why so expensive?

It’s a tad more than a hole

Well it’s quite close to your house, the S/E design costs won’t be dirt cheap, the retaining wall and it’s foundation will be quite costly, there is surface water drainage to deal with, grab lorry costs, it will need a decent size digger, you might need services relocating.

The building is best made in block work, I think. Roof probably needs to be block and beam / steelwork.

 

[MargoSmith]

It's difficult to tell from the pictures, but if you have the space, I would consider a smaller retaining wall, part way down the slope - I believe that something up to 1.2m can be achieved with fairly limited engineering input. If you then left a small separation between the front of the wall and your new building for a suitable drainage system you could avoid any damp issues. Block and beam might be suitable for a roof/floor and could span the gap back to the original ground.
You need to be aware of any services - this sort of work often exposes gas, electric, water and drains. Sometimes you can work round them but otherwise they can be expensive to relocate.

Nice idea, so have a slope and a smaller retaining wall, and effectively just bridge over the gap to the roof.

 

[George_engineer]

It's difficult to tell from the pictures, but if you have the space, I would consider a smaller retaining wall, part way down the slope - I believe that something up to 1.2m can be achieved with fairly limited engineering input. If you then left a small separation between the front of the wall and your new building for a suitable drainage system you could avoid any damp issues. Block and beam might be suitable for a roof/floor and could span the gap back to the original ground.
You need to be aware of any services - this sort of work often exposes gas, electric, water and drains. Sometimes you can work round them but otherwise they can be expensive to relocate.

1.2m wall with a large surcharge (sloped soil) may still need engineer input. The standard designs usually assume flat soil.

 

[stuart45]

NHBC recommend SE design for over 600mm. LABC say over 1000mm.
Although a lot of people think a 9 inch brick wall is OK for a 3ft high retaining wall, as George says above sloping ground makes a big difference.
Here's one I looked at rebuilding.