Foundations

[Astraeus]

Evening folks,

Our application has just gone in for an extension.

The side extension will abut a boundary where our driveway is 1m higher than next door's driveway. There is no party fence, only a drop off from our driveway to theirs (quite the mess!).

As it is only a single storey extension, I don't imagine that our foundations would need to be any deeper than 1m, in which case they won't come close to undercutting the neighbour's foundations such that a Party Wall Act notice would be required. Or at least that's my thought. Is it likely, from anyone's experience, that building control will ask us to dig foundations beyond the 1m height difference between our properties and into the ground proper, i.e. the clay beneath the level of my neighbour's driveway?

 

[Astraeus]

I've just seen this thread - https://www.diynot.com/diy/threads/building-near-retaining-wall.421924/. if you can imagine that my proposed extension is the blue garage on that drawing, that is the situation we're faced with. So would we likely need to dig below the retaining wall or could we site our foundations in the land retained by the retaining wall?

 

[^woody^]

Foundations should be lower than the lower ground level. Whether that means 1m lower will depend on the ground, but you should expect at least 600-800 lower