Hi All,

I'm after some advice on how close I could realistically dig back to my garden office.

My garden office is built on an (old) raised patio at the back of our garden (rough sketch attached). At the moment the old patio extends out from the front of the building by about 1m but doesn't have a wall in front of it as we've already taken it back by a slab so I had to remove the old small retaining wall.

In an ideal world what I would like to do is completely remove all the soli in front of the building and put in a new block retaininng wall and foundations and then build a stepped decked area. What I'm unsure about is how close I can dig to the front of the office building where it sits on it's slab base. Am I okay to dig back right up to the front of the building (marked in red) or should I only dig back a certain way and leave some of the current level in front of the building?

Thanks in advance!

James

2 options... 

 

Drive piles (eg fence posts) as either the permanent wall or as a temporary retaining wall to allow you to lay blocks. 

 

Or just dig back in narrow sections, say, 500mm or 25% of the length, whichever is smaller, at a time to limit any loss of material. 

 

What I would not do is just dig it all out as you would probably undermine what the office is sat on. 

As a rough guide, the building load on the ground extends downwards and outwards at 45^o If you dig outside of this zone you should be OK, but your proposed wall is inside this zone so you will need to do something like @George suggests.