Extension against neighbours extension

[jojothefirst]

Plan to do everything properly if and when we decide to do this project but just trying to get my head around this at this stage..
Looking into building a single storey side return extension to make kitchen bigger and incorporate 2 outside buildings.
Our neighbours extension forms the border of our property's so my thought was to tie into there extension.
Spoke them about this and creating a party wall award but they have refused on the grounds it will affect them being able to sell there house and could cause damp problems.
If i go down the route of getting surveyors in are they likely to go in my favour?

Alternatively, is there a way to build a single skin wall on my land next to there extension and insulate the gap in between.

Any input appriciated.

 

[mrgobby]

If it’s their extension wall and within the boundary on their land then it’s their wall on their land and I can’t see your chances being very high

 

[^woody^]

You have the right to create a new party wall astride the boundary, but not to use their existing wall on their side of the boundary.

You would have to knock the wall down, build a new one and pay for the lot of it.

Or build a completely new wall on your side of the boundary and this will need to meet the standards of an external wall and maintain a gap between the neighbours wall

 

[johnny2007]

Explain to them that the alternative to using their wall to tie yours is to leave a 4 inch gap which will attract leaves , birds (alive and dead), mammals (alive and dead cats mainly), rodents and inevitably dampness.
Instead, i have never seen damp on a party wall.
I say 4 inch gap assuming they built on the boundary.
Of course, if they've left a larger gap (as they're supposed to), there would be a bigger gap but same problems.

 

[garyo]

In these circumstances can you build 10mm away?

 

[johnny2007]

If you are within your boundary yes.
Especially if it's permitted development.
Speak to them and make them reason.
A small gap between extensions is trouble for everyone.

 

[garyo]

My view is that if they've built right up to the boundary then it's only fair that you can too.

Have you looked at their roof verge detail (assuming it's a monopitch roof) and established whether they're overhanging you, or whether they're actually 50mm set back to accommodate their dry verge or whatevers going on up there?

 

[Edddd]

Maybe you could get an initial consultation with a surveyor? There is a presumption that the party wall process should enable work to take place, so the surveyors would probably reach a binding agreement that would allow you to proceed without the problematic gap. Unfortunately it could be quite expensive if that involves demolishing and rebuilding the existing wall.