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AIBU?

Share your dilemmas and get honest opinions from other Mumsnetters.

AIBU with my neighbour about our boundary

156 replies

ThisPinkCrow · 17/03/2025 20:26

Hi all,

We have just bought a house in London and are new homeowners. My adjacent neighbour has also bought their house at the same time as me and has begun doing works to it.

My neighbour wants to install EWI and a French drain along their main wall that is only accessible via my side access. I am seeking advice about what people would do in my position because it's not clear to me. Strangely, I can't find any examples of my situation on the internet. I would have thought this is not an uncommon thing. I want someone to tell me YABU/YANBU or if I'm missing anything really obvious here.... thank you to anyone who reads this.

The neighbours house is extended at the rear on the first and ground floor while mine is not extended at all. Both of our houses have damp issues on the ground floor. The neighbours wall is solid up to point of their extension, the extension has a cavity wall above and below. Among other things such as a French drain, as part of a multi-pronged effort to tackle this damp, my neighbour wants to install exterior wall insulation of ~ 10 cm thickness on all the sides of their house. I want to state at the offset I want my neighbours to be able to put insulation on and improve their wall. At the same time, I don't want to agree without being fully informed and regret it later.

The side wall of the main living area of their house borders the full length of my side access. My side access is only accessible to me by my gate. My side access leads straight to my garage at the very back of my garden. Their main wall is stepped out ~ 10cm in places for the two chimney breasts, before it recesses back into the main wall. At the top their roof soffits go another ~10cm beyond the chimneys, and then the roof gutters another ~ 10cm, so overall the furthest part of their structure projects give or take ~30cm from the main rendered wall.

The titles of our properties indicate an approximate straight line boundary along the wall, which then joins the garden fences and the driveway hedge/brick.

The neighbour suggested initially that the boundary follows a straight parallel line from the chimney breasts, so the gap sandwiched between their chimney breasts is their land, which means they can insulate and they just need permission for access and nothing more.

My view was that logically the boundary between our plots would follow exactly the shape of the main fixed structure which is the foundational wall, so along the main recessed wall, then following chimney breast 1, back to the main wall, following chimney breast 2, back to the main wall until it meets the garden fence which aligns with the main recessed wall exactly.

I thought that this is the boundary because the corners of their main wall precisely align with the edges of fences / connecting boundary features that separate our properties at the front drive and at the back garden. This is also the case for other properties with chimneyed walls along the same road. There is also a side access garage extension on the same road which has been built right up to the other house's wall since forever, including fully wrapping around the chimney breasts of their neighbours wall. Not that I would dream of doing this or that it would be approved these days but it seems indicative of where a technical boundary is. There is also a more recent side extension on the same road that looks like it stops not far from the adjacent properties roof structure, but my assumption there is that this was stopping some distance short of the main boundary which is the wall.

The insulation they proposed to put on would not go further than their current chimney breast depth, so in effect their wall would become straight as the parts of the main wall would be brought outwards, with insulation, to the chimney breasts which would be re-rendered but uninsulated (insulated internally) - so that the minimum width of my current side access (2.3 metres), which is set by the protrusion of the chimney breasts, is unchanged. The total area here that would be used by the insulation along this small strip that goes along their wall is only about 1.2 metres squared (12 metres length of their wall x 0.1 metres width).

I said OK to most of this, if that strip is technically my land then they can have that. Additionally I said that they can put the drain adjacent to their newly insulated wall provided that we agree the drain isn't changing the boundary, which we would both then agree follows the shape of their now insulated main wall.

The one material amendment I suggested is a ~ 2m length gap of uninsulated render at the end of their rear extension on the ground floor (which is ahead of the end of my unextended house) - because their extension has a cavity wall and the damp issues are not significant there and something can be done internally. If I wanted to do a rear extension and extend this rear extension out to the side, I would prefer to have all the space I can get even if it's just 10cm. I felt like this was a reasonable compromise where we both got enough of what we wanted - they got 90% of the insulation and the drain, I did not have the most usable width removed from my side access if I wanted to bring vehicles through. Then we would do a normal boundary agreement between ourselves and register this with HMLR which is very cheap and easy to do.

After hearing this the neighbour has paid a lot of money for a surveyor to do a determined boundary report to clarify the boundary. I said I would accept the outcome if the report explained why my thinking was incorrect, then they would seek to register the determined boundary with HMLR.

The report caveats that this is the surveyors opinion because they do not have the original plans, but the surveyor says that it's most logical that the boundary at the wall goes up to the end of my neighbours roof gutters. So my thinking is wrong, and the neighbours thinking that their boundary extends from their chimney breasts in a straight line is also wrong.

My reading of this is that all the land projected downwards from the edge of the neighbours roof gutter is theirs. Basically it's saying they own ~ 25-30 cm of my side access on the ground and all the airspace above it. The report doesn't references other houses locally or on the street, other than to say they also have projecting roof gutters, nor does it explain how the current garden and drive would be visibly offset from the roof edge were this the true boundary, it more seems to assert the conclusion based on the surveyor's experience.

If this is the true boundary then the neighbour does not need my permission to do improvement works to their wall (the insulation and the drains come within this 30 cm strip) they only need permission for access, permission which I would obviously grant if I believed the surveyor is right.

My view was that the gutters and soffits at the top could be classed as a minor trespass at most, or in effect they may be allowed to overhang the boundary because it's not bothering anyone. I was never remotely concerned or bothered about this overhang until I read their surveyor's report. This was not mentioned when I was purchasing my house but I don't blame anyone for that. I don't care about the overhang as long as the downpipes, which come down adjacent to their chimney breasts along their wall, don't discharge on my side and they do not, it doesn't cause any harm to me and if they wanted to maintain that they'd always be given access immediately.

If I accept the edge of the gutters as the boundary, this means my side access can be narrowed another 20cm by the present neighbours or (more likely) future owners if they ever choose to do so and I have no say in the matter. If I also choose to put minimal 10 cm insulation on my wall on my side of the side access (which is currently uninsulated just like the neighbours is), then in the worst scenario the minimum width along my side access at the pinch point could be reduced to less than 2 metres, and I can't really accept that if I want the option to bring vehicles through in future.

I am not really sure what happens next at this point. I just read the report and I've messaged my neighbour to tell them I don't feel like the outcomes are well explained and that if they believe the outcome, that they own ~30cm of pathway in what I perceive to be my side access, and seek to register this boundary I would have to dispute it reluctantly. I've also asked them to forward my details to the surveyor to get in touch with me so they can be better explained to me in case I'm just not getting it.

I'm still on good terms with the neighbour from my perspective, like I'm trying to be difficult, and we're still communicating with each other without any problem, and I don't have any problem with them either. but obviously this is starting to seem like it's about to go off the rails.

So.... AIBU to my neighbour here? Am I just crazy and this is what the boundary really is? If the situation was reversed and I just bought their house and they had bought mine, I do not believe I would assume that I owned part of their side access because my house's roof soffits and gutters slightly overhanged onto their side.

However, if I wanted to insulate my side wall and add a drain to reduce damp, I think I would be completely normal to want those changes and to hope that the neighbour wants to try to work with me to allow them, and to arrive at some compromise which isn't perfect but works well enough, while maintaining an agreement about the existing boundary.... that's what I've tried to do. I've not said no to anything that impacts their ability to tackle their main damp problem that they've asked of me until this point.

But if they want me to accept a determined boundary is somewhere massively different than where I thought it was in order, and then register it, in order to then tackle their damp then I'm not sure how that doesn't lead to solicitors and lots of money going up in flames. I wouldn't be bothered at all if the side access was another 20 - 30cm wider at its narrowest either but it's not and vehicles seem to only get bigger with time, equally I would be worried about what accepting this proposed boundary would do to my house value.

Thank you to anyone who made it to the end of this long post.. I tried to shorten it but it's still lengthy.

OP posts:
Thread gallery
11
Nowvoyager99 · 17/03/2025 20:27

All that text and no fucking diagram!

Are you new?

ThisPinkCrow · 17/03/2025 20:28

Nowvoyager99 · 17/03/2025 20:27

All that text and no fucking diagram!

Are you new?

I am completely new, it's my first post here... I will try to draw a diagram if that helps. Not sure how I would do it but watch this space.

Thank you for the reply and suggestion.

OP posts:
Mingenious · 17/03/2025 20:29

It that your dissertation submission?

AgathaMystery · 17/03/2025 20:30

Nowvoyager99 · 17/03/2025 20:27

All that text and no fucking diagram!

Are you new?

This. Come on. We need the schematics.

CountryQueen · 17/03/2025 20:32

Blimey. Nobody is going to read all of that

bellabasset · 17/03/2025 20:32

You get a surveyor to look at it and have a formal party wall agreement in place. The neighbours fund it.

skilpadde · 17/03/2025 20:33

So much text; I lost the will to live half way through. Maybe a consultation with an architect would help?

Edited to add:
Ooh, @bellabasset suggested a surveyor… yes, do that. You need an expert, someone you’re paying in exchange for the life story on your house.

ThisPinkCrow · 17/03/2025 20:34

Ok I've read the feedback, it's my first post ever here, I will cut it down and resubmit.

OP posts:
Nowvoyager99 · 17/03/2025 20:34

ThisPinkCrow · 17/03/2025 20:28

I am completely new, it's my first post here... I will try to draw a diagram if that helps. Not sure how I would do it but watch this space.

Thank you for the reply and suggestion.

Edited

Fair enough.

We LOVE a diagram.

Thanks in advance.

Foodylicious · 17/03/2025 20:36

If you have just bought, can you go back to your solicitor? and tell them it doesn't seem clear that they entirely established the property boundaries before your purchase.
Not sure how much they will help (for free) but it might be that you need someone to look at the boundaries for YOUR property.
You can then see how these do/don't match up.

BadSil · 17/03/2025 20:37

Don't take it personally @ThisPinkCrow . It's just that any parking thread or neighbour dispute must come with a diagram. It's Mumsnet law.

BobbyBiscuits · 17/03/2025 20:39

Diagram please. It's impossible to guage anything you've said in meaningful terms without it.

ThisPinkCrow · 17/03/2025 20:40

BadSil · 17/03/2025 20:37

Don't take it personally @ThisPinkCrow . It's just that any parking thread or neighbour dispute must come with a diagram. It's Mumsnet law.

I don't take it personally, it is a long post. I tried to shorten it. I think it's fair to ask for a diagram instead of expecting most strangers to read that much, not that surprised by the responses! I did think of doing a diagram but also felt that text would be easier actually in my case, but evidently it is not. Making the diagram in Powerpoint / trying to now..

OP posts:
parietal · 17/03/2025 20:44

You’ve written very clearly but a diagram would still help.

definitely get your own surveyor and look carefully at the land registry for any information on the precise property boundaries.

CatsWhiskerz · 17/03/2025 20:48

Yes, you need a surveyor to accurately decide boundaries. Not read the whole post as it's too long so will catch up with the concise version and diagram

LoveWine123 · 17/03/2025 20:50

I’m sorry, I lost it on the 4th paragraph and there were a thousand more to go. It’s very difficult to picture what you are trying to explain.

ThisPinkCrow · 17/03/2025 20:53

LoveWine123 · 17/03/2025 20:50

I’m sorry, I lost it on the 4th paragraph and there were a thousand more to go. It’s very difficult to picture what you are trying to explain.

I understand, I am creating the diagram! Sorry!

OP posts:
PaintDecisions · 17/03/2025 20:57

Is there a TL:DR? Executive summary?

stayathomegardener · 17/03/2025 21:01

Welcome to Mumsnet!
Any boundary issues and it's a standard reply to insist on a diagram so the first response is actually quite funny.

Look out for penguin bollards on parking threads and ' have you thought about cancelling the cheque' when posters miss the obvious.

Anyway back to your dilemma, I couldn't concede this easily given it could scupper any future plans you may have or a sale.

I think you need the neighbours to pay for an objective party wall survey.

You may also actually have legal cover on your house insurance which would be perfect in dealing with this one step removed from your neighbours.

Mandoidi · 17/03/2025 21:01

I think that might be the longest post ever on Mumsnet! ❤

Anyway I'm here for the diagram because I am interested in understanding your issue. I don't have any knowledge to be able to help though

Frostynoman · 17/03/2025 21:02

You need to get your own surveyor here - the other surveyor is not acting for you, they are acting for your neighbour - you need representation.

Find your boundary info from your conveyancing bits - they should have a copy from the land registery. You can also buy the plan for your neighbours house for a few £ to see where their boundary lies.

Insulating a damp property with modern insulation is only going to trap the moisture in - it will not solve the issue. A French drain is a good way forward (unless it is taking your land, which is not).

Don’t hand over land to your neighbours in the hope they’ll let you build right up to their extension - they’re already being cheeky about taking your boundary, I wouldn’t have much faith that they’d allow you what you want in the future.

VJHB · 17/03/2025 21:06

I thought their boundary would be in line with their furthest point on their house. In your paperwork TP1 when you bought your house there should be more information to do with covenants to do with the land and what access they might have.

FOJN · 17/03/2025 21:06

I'm quite a patient and diligent reader of long posts but you have defeated me.

Contact your conveyancing solicitor for advice about the boundary. MN will not know because there are general rules but they can vary.

AffableApple · 17/03/2025 21:07

I'm probably wrong, but I seem to have got the impression from other posts about work being done in the past on MN, that the neighbour has to pay for a surveyor or lawyer or someone to act on your behalf? They want the work done, not you...

MissBridgetJones · 17/03/2025 21:14

I'm eagerly awaiting the all important diagram....

If you have just purchased do
You have the land registry plans to hand? (Not that you should post them here!)

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