Diggin Foundations ourselves

k25

We are planning to build a small single storey extension on the rear of our
terraced property.
Next door have also built a similar extension which is larger than our proposed
one,
But the wall for their extension is on their land i.e. doesn’t cross our shared
boundary but is very close to the edge...

But thinking about it the foundations for their extension will probably "spill"
over/underneath our land, and in the place where we want to put our foundations.

Does this present a problem when we undertake our groundwork’s or is there a
simple method to "tie" our foundations in with theirs.

maple41

You must get professional help from a surveyor. Legally, now there is something called a Party Wall act which imposes certain restrictions if you dig or otherwise potentially interfere with an ajoining property within a metre of the boundary. Your neighbour might agree to the work but if you go ahead without agreement they can force you to stop and you would be liable if there was any damage to their property.

weeg

Assuming you are in England or Wales, the Party Wall Act applies, and your neighbour should probably have sought your agreement before building their extension - this means they can't really kick up a fuss about your foundations, but you will have to agree the details with them prior to starting work.

It's generally considered a very bad idea to tie seperate sets of foundations together. It's just trouble, so don't go there.

MJMum

Party Wall act

Not to mention, if you go ahead without your neighbour's permission, they can hold you nicely to ransom if you want to sell the property (which you won't be able to without the right piece of paper from them). So do it right from the start, even if that means you have to have a slightly smaller extension.

courtjester

I imagine that this will be subject to building control (regs), so you might want to contact the BC officer at your local authority and get them to come and see you before you embark on any works - they will need to see the bottom of the trench before foundation works are put in.

Are you confident with the engineering design of these foundations as regards depth and relationship to themain house foundations. Also, do you know where the drains are?