Can I build upto the line of junction on a mid terrace property?

Hi

General question. I hope it's in the right area.

I will be getting a 6m x 6m single storey rear extension done on my mid terrace property. Atm I have no rear extension. Both of my neighbours on each side have 3m extensions built. My friend has recently done a 6m extension and he said Building control asked him to leave a gap between his neighbours extension and his newly built one which has left me confused as I've seen extensions where there are no gaps.

My question is:

1) Can I build my extension walls right upto the line of junction(boundary line) to maximise space and avoid any gaps?

2) why would a building inspector stop me from doing this and is it building control issue or neighbour issue?

3) As I want to build my own wall upto the boundary line do I just need to get an agreement with my neighbour that I'll be excavating near his wall?

I'm just worried that I don't want building control to make an issue of this. Also, for a rear extension is a full pland submission to LABC advisable over a building notice?

I would appreciate advice from tradesmen who have experience in this.

Roger,

If your extension requires planning permission then the council can enforce certain criteria on you but that wouldn't necessarily mean leaving a gap. (In my opinion leaving a gap is worse). If you are building on permitted development which I guess you are trying to do at 6m then you just need to serve the correct party wall notices, I think it's letter 4 for building a up to the line, you'll also need the first one if you are attaching in any way to the neighbor's property (even waterproofing etc if you want to be strict) and the 3/6m one for digging foundations near by. You can combine them into one letter. They can agree, or insist on a surveyor which adds cost, but the final design comes down to you and your architect and to some extent the building inspector but they shouldnt have a problem with it as long as the plan is sound (and planning department if you are outside of permitted development). Clearly if you end up causing any damage or negative consequences to their property then you are liable, but then that's what insurance is for.

Building regs will always apply but again they don't normally force you to leave a gap or not.

As far as building regs approval is concerned a Full Plans Submission is always better than a Building Notice apart from the simplest of jobs.

Thank you both for your replies. . I was worried that I'll lose far too much space if a unnecessary gap was left so glad you guys cleared that doubt.

To confirm I applied for prior approval and neighbours did not object so it comes under permitted development.

My follow up questions are:

1) do building control request for any party wall agreement documentation or is this just between me and the neighbour and nothing to do with building control?

2) I'm planning to build my flank wall solely on my land and not astride the junction so won't I just need to give them notice about excavating near their properties?

Any recommendation links for tenplates?

Roger

Building Control have no knowledge of or interest in PWAs. They exist simply to allow you to carry out work which your neighbours might otherwise prevent, and (as the courts have held) to some extent protect you from spurious claims of damage.

The three issues for building on a boundary or next to another property are fire spread, passage of sound, and prevention of damp. Deal with those (via suitable design) and building control can't say jack.

If its not astride or joining then you should be ok with the letter for wholly on your land and the 3/6m letter. If you are close to your neighbour's wall you may need to cut into it for waterproofing depending on what our architect has planned....which would be party structure notice, strictly.

If you are leaving a gap then you'll want at least a minimum space to clean and maintain yours and their wall in the future.

Templates are on the gov.com website: https://www.gov.uk/guidance/party-wall-etc-act-1996-guidance#example-letters

Which letters you send don't really differ much except the waiting time, which can be waived anyway if your neighbour agrees. An agreed surveyor can be helpful for both parties....stops them blaming your works for existing cracks as much as it protects them from any damage caused by your building. But nobody likes paying the extra money!

Don't forget if you build up to the boundary no part of the extension should overhang the boundary (except the foundations) without the neighbour's permission. So you need to be careful with any roof eaves or verge etc.