adjacent rear extensions - leave the gap or build a party wall

Your neighbour is a cretin. As Woody said if you were building the houses today you wouldn't build one wall and then build a separate wall alongside it, you'd have a shared party wall, the extension is no different.

If you are both building an extension at the same time I do not see why you need a party wall surveyor at all, you should both assent to each other's notices. If you are thinking of using the surveyor to draw up a new party wall agreement then try to get a fixed fee quote. It really shouldn't be any more than £500 but sadly their are some absolute sharks out their who just take the ****. I read yesterday about a chap who charges £320/hour!
 
Get a party wall arrangement and built. It will pay you both; no rubbish trap so no build up that will cause damp, more space in the rooms for both parties. Warmer!
 
The boundary between two attached houses is not rocket science - it's smack bang center of the party wall and (most likely) then just square off the house.

I know this is a bit off-topic but the boundary between two attached houses is not always at the centre line of the wall. On my semi it is 20cm over the centre line in my favour, the original post from the 20's is still bolted to the wall, the neighbours many years ago built 35cm from the centre line, plus I have fence posts over the centre line. I think the reason may be that the road is a cul de sac and they angled the back gardens slightly so as to shape the plots in the best manner. I am about half way down the road so a lot could be the same. And looking from above the rectangle of the plot is not quite in parallel with the houses. However in the front the boundary is the centre line but it would look visually odd were it 20 cm over.

Just saying you do have to be a bit careful to check this stuff. The house is not always on the centre of the plot, the side of the houses may not be in parallel with the back gardens. So by building square off the house you may not be following the line of boundary.

I don't mean to put the op off but assuming the centre line is the boundary line might not always be the right approach.

If there is a discrepancy one way forward might be to re-register that section of the boundary with the Land Registry by paying a fee. Then there would be legal certainly and you can build on the centre line.

I am not sure if this has been mentioned but there are foundation benefits in not having gaps between extensions because of the 45 degree line.
 
Last edited:
I know this is a bit off-topic but the boundary between two attached houses is not always at the centre line of the wall. On my semi it is 20cm over the centre line in my favour, the original post from the 20's is still bolted to the wall, the neighbours many years ago built 35cm from the centre line, plus I have fence posts over the centre line. I think the reason may be that the road is a cul de sac and they angled the back gardens slightly so as to shape the plots in the best manner. I am about half way down the road so a lot could be the same. And looking from above the rectangle of the plot is not quite in parallel with the houses. However in the front the boundary is the centre line but it would look visually odd were it 20 cm over.

Just saying you do have to be a bit careful to check this stuff. The house is not always on the centre of the plot, the side of the houses may not be in parallel with the back gardens. So by building square off the house you may not be following the line of boundary.

I don't mean to put the op off but assuming the centre line is the boundary line might not always be the right approach.

If there is a discrepancy one way forward might be to re-register that section of the boundary with the Land Registry by paying a fee. Then there would be legal certainly and you can build on the centre line.

I am not sure if this has been mentioned but there are foundation benefits in not having gaps between extensions because of the 45 degree line.

The boundary between two attached houses is always centre of the party wall. Where the boundary then goes is fact and degree. In the OP's case, it's presumably where the existing fence or whatever is.
 
Legally a boundary is where both parties agree it to be. At the back of the house it doesn't have to be the centre of the party wall. They can also change over time. It is just a point that both parties agree on.

It's for these reasons they are so expensive to resolve if you get into dispute.

I have checked this out and what I have read is that the centre line is clearly a strong indication but not the only factor. Like my neighbours have written to me saying fencing 20 cm over the centre line is on my land. As I said they built 35cm from the centre line so that is another strong indicator. This all happened way before I bought the house.

You said in another thread houses are 'sold as seen'. The deeds said that side was my fencing and it was in the ground 20cm over right up to the house. There was no boundary dispute disclosed to me.

So then why should it not be a boundary in this instance???
 
Last edited:
You said in another thread houses are 'sold as seen'. The deeds said that side was my fencing and it was in the ground 20cm over right up to the house. There was no boundary dispute disclosed to me.

A fence is not a boundary. A boundary is an imaginary line.

The position of a fence, the ownership of it and the maintenance of it are all distinct from the position of a boundary and the obligation to maintain (or secure) the boundary.

I can't comment on why no boundary dispute was disclosed or if one even existed.
 
But if the fencing has been in place since the house was built, and both parties accept it, then it can become the boundary line.

Alternately if the fences get moved and it is not challenged, that can become the boundary line. As I said, if you don't have boundary posts the boundary is a line where two people agree it to be. After all you can agree to change the line of boundary and then re -register it at the land registry.

The thing is this. If you are planning an extension between two houses and you see your neighbours fence well over the centre line and it is their fence line on the deeds you do need to exercise caution because some people get obsessed about it, is it really worth getting into a very expensive dispute?

You say a fence is not a boundary. Say we are neighbours and I have an apple tree I have tended for many years right on my side of the fence. You come round and say 'a fence is not a boundary, the tree is on my land, I wish to cut it down.' How can that be fair???

I am not trying to wind you up but do you have any legal argument for saying 'a boundary between two attached houses is always centre of the party wall.' I am not a solicitor or anything but it is not a legal argument I have come across.
 
If you want the most efficient abd possibly cheaper method can you not get 1 groundwork team in to do the foundation for both projects at the same time?

Its silly to dig 1 foundation, then do another right next to it a bit later on.
 
do you have any legal argument for saying 'a boundary between two attached houses is always centre of the party wall.' I am not a solicitor or anything but it is not a legal argument I have come across.

Yes. Established law

The boundary between the physical houses is the centre of the party wall.

This imaginary line runs through to where it meets the external face of the front and rear house wall.

Then, this imaginary line shoots off at whatever angle is defined by the deeds. It would commonly be at 90° to the external wall, but not necessarily so.

The placing of a fence or wall or row of daffs will not determine the boundary but may well define it for the sake of convenience.

If a garden boundary line is in dispute or undefined, then it can/will be determined either by mutual agreement, or by determination of its "most probable" position by a suitably qualified surveyor. The surveyor will use his judgement to determine the most probable line from the external house wall to the end of the garden.

Moving of a fence will not define a boundary in itself. If such a fence is moved for the specific purpose of obtaining another's land (not just by mistake), and this excludes the other person from his piece of land and this is done for a specific period of time, then that will give the person the right to claim the piece land and move the boundary. But it's no longer automatic and can be challenged by the original land owner.

I wont be able to cut your apple tree down just because I say its on my land. I would need to prove where the boundary is. However, I could make sure that I have a damn big wasp's nest near to the tree.

When you build on or near the boundary, the common sense thing to do is just tell the neighbour that you will be building next to or on the fence line and ask them if they have a problem with that and if they have a problem with your understanding of where the boundary is. It ain't difficult.
 
Established Law. Are you able to be more specific? Do you know of any actual cases???

It would be most welcome if these angles were specified in the deeds but sadly they are not. You can't even rely on plot measurements in deeds because the building might not be central on the plot. Surveyors always evaluate by what is physically on the ground.

The thing about determining a boundary is it is a risky process as the surveyor could make a basic error that will bind both parties. It is better to agree the boundary beforehand and have the surveyor plot it.

The reality is if your neighbour moves a fence onto your land it is not a straightforward process to defend it. Possession is nine tenths of the law.

Re the apple tree - you have said the boundary projects from the centre line at an angle proscribed in the deeds. Therefore you have proved the boundary line to yourself and can cut the tree down should it be inside 'your' boundary.

Re building near or on the boundary - when does common sense ever come into it??? You have this fixation the boundary is at the centreline and heads off at an angle proscribed by the deeds. But when I bought this house my fence was 20cm over that centreline and has been like that for forty years!!! Pull that fence up and I'll have you for criminal damage.

I hope you can see how difficult it is if your neighbour is difficult.
 
Thanks everyone for the discussion

Footsoldier, Woody - fortunately our plots are rectangular and as far as I can tell the fence does go from the middle of the wall between houses, so no issue here.

However, our neighbours do not want to share the wall. They have checked and asked around and the advise they've got is - don't go into it, it is more trouble than benefit. So it is agreed now between us that we will build separately. They are ready to go to such an "extreme" as even build the foundations on their side only, effectively setting the extension wall back from the boundary line as far as 20 cm.

However, from my point of view - the question how we build as close to the boundary line as possible is still very much relevant (the whole house=plot is only about 5 meters wide, so loosing 20 cm stepping back, then 30 cm thickness of the wall = half a meter looks like a bad option to me).

Questions we have related to this situation:
- How big should be the gap between extensions? I've read about 15 cm in some sources, but one of the architects in our bureau has told us on Friday that we can build as close as we would like, say an inch, and then just cap this small gap with some flashings on top to prevent ingress of water into that gap
- Can we build joint foundations? Does it require party wall agreement? (and as in the common separation wall situation - who's responsibility it will be in the unlikely event of say subsidence?)
- Can they build part of the foundation and then we kind of "stitch to it" when building the "continuation" of foundation to our side - this question arises because we have glass conservatory on our side, and extending foundations fully to our side will require its demolition, which will probably not happen until we actually start the works few months later then our neighbours.
- Is there a way to build some kind of "specialist" foundation that will not protrude sideways from underneath the wall at all? This will potentially be the simplest - they will build whatever they want not getting to our side, and I will build on our side separately something which will allow us to get as close to the boundary line as possible

Thanks,
D
 
well, now I am fuming... just got a call from my wife that our neighbour came about to say that they do want a proper gap, of whatever width it should be foot or so.. Insanity I think, loosing so much valuable space... I don't want to fight with them, but it is sad situation
 
Your neighbour has absolutely no right to dictate what you do on your side of the boundary. You are perfectly entitled to build right up to the boundary and project your foundation over the boundary if necessary by serving a line of junction notice and there is not a damn thing your neighbour can do to interfere.
 
It's really crazy not to agree a proper party wall, but I guess there's no reasoning with some people.
 
Your neighbour has absolutely no right to dictate what you do on your side of the boundary. You are perfectly entitled to build right up to the boundary and project your foundation over the boundary if necessary by serving a line of junction notice and there is not a damn thing your neighbour can do to interfere.

Yes, indeed. But the problem is now that they build first, so
(1) they can as well to go with their foundations to my side and then what? Can I use their foundations (i.e. extend them further to my side) to build my own and to build a wall on top of these joint foundations
(2) I will need to take care I do not undermine their foundations when I am building mine
(3) they now will be able to build and properly render outside of their wall, and if afterwards I build too close I will not be able to render it, and if the gap is not so small that we can cover it with flashings then elements will be getting in...

nasty..
 
Back
Top