AIBU to think that my upstairs neighbour cannot decide to build an extension on my flatroof without my explicit permission?

[BaleOfHay]

London converted terrace. My upstairs neighbour (with whom I share the freehold of the building) has submitted a planning application to build an extension out on to my flat roof. AIBU to think that A) he's a CF, and B) they need my explicit permission for such a build? Surely he can't build on my roof without my permission??

I believe he’d need to secure a ‘flying freehold’, but I don’t know what that would involve.

@Apfelkuchen - apparently not as we co-own the freehold. But he seems convinced he has the right to go ahead and apply to build on the roof. It seems utterly bizarre!

Well he asked for permission, hasn't he, by submitting a planning application?

You just refuse it. I'd think you'd have a pretty strong case, being his direct neighbour, surely?

Report to council and planning.

I think you need proper qualified advice, and quick. Your foundations might not be built to support the weight of his extension, for a start!

There are all sorts of issues here, the foundations, your walls may not be designed for a second floor, your roof and joists would certainly need replacing.
Potentional noise from.above, let alone the intrusion whilst building work done.
It would have to be 'no' from me.

What would happen if he built it and then you decided to knock down your own extension? 😂

I have submitted an objection but can't understand how he has a right to apply to build on my property without my consent.

Anyone can apply for (and receive) planning permission for anywhere. I could apply to build a house in my neighbour's garden, doesn't mean I could legally build it though, even if I was granted PP.

You will need to get legal advice though as it sounds like there is a risk he will start building without proper consents.

Anyone can put in a planning application for work that is not on their property. Someone did this about our garden! Its not illegal, but the homeowner (you) needs to object to the Council's planning department within the time frame - usually three weeks i think - and get urgent legal advice. Apart from structural issues, there could be ones to do with visual appearance.

I'd hope that the planning dept would take my objection seriously?

Are the foundations even deep enough to take another storey?

You can actually apply for planning consent on property that doesn't belong to you. If he's serious and you are joint freeholders you need to check that he doesn't have the right to build on your property.

The planning decision does not need to enforce boundaries or lease conditions. You need legal advice as to how to assert your rights as a joint freeholder and neighbour.

The Council will probably not be primarily concerned with ownership - that is the legal side that you need to get advice on.

With respect, given how serious this is, you should be talking to a solicitor and/or surveyor not asking Mumsnet....

Seek legal councelling.

I have spoken to a surveyor and raised my concerns with him. But I was not formally informed of the planning application and only found out about it because someone else saw it - so I am trying to work out whether it is all a flight of fancy that will be thrown out by planning when I tell them that I do not give permission for him to build on my roof or whether I need to go down a more formal route.

As others have said, planning is not concerned with ownership, the planning authority will not take into account your objection on this basis.

You need to review your lease carefully to determine whether you own the flat roof (sometimes, your lease demise might only go up to the ceiling and the roof is part of the freehold). If it is within your demise, he obviously needs your agreement. If it’s part of the freehold, he needs the freeholder’s agreement - as you own 50% of the freehold you can likely block it but none of this is straightforward and you should see a solicitor.

Also, you still need to live with this person so how about start by having a chat with them?

Well, you don't actually know he has a right yet...

You or more appropriately him would need a structural survey to check the foundations, roof etc. Unless your bit was designed to have a second floor it would be unlikely to be suitable and probably need rebuilt.

Do you own the area of land upon which your extension is built? You need a solicitor to stop them going ahead. You may have legal cover with your house insurance or trade union membership. Strictly speaking he does need your consent to apply for planning permission but in my experience,local authorities ignore this point.

I'd make an appointment with a solicitor now and have them write a letter informing him of the consequences if he starts work. (If it's a flat roof the foundations probably aren't deep enough to support a second floor).

I'd be installing velux, skylight windows in your ceiling asap!

I typed "Can my upstairs neighbour build an extension on my flat roof" into Chat GPT and got a pretty comprehensive reply.