Builders sometimes say you can "just build astride the boundary." Under Section 1 of the Party Wall etc. Act 1996, that's only true with your neighbour's consent - otherwise you have a different, still-workable route that doesn't need their agreement.
There are two different routes, and they're easy to mix up. Section 1(2) covers wanting to build a wall astride the boundary - but this needs your neighbour's consent under Section 1(3), and if that consent isn't given within 14 days, Section 1(4) means you can only build wholly on your own land instead. Section 1(5) is the separate route for building wholly on your own land from the start - no consent needed, just one month's notice.
Only with your neighbour's consent. Section 1(2) lets you serve notice of your desire to build astride the boundary, but Section 1(3) requires your neighbour to actually consent before it can be built half on each owner's land, with costs shared proportionally. Without that consent, you can't build astride.
Under Section 1(4), if your neighbour doesn't serve notice consenting within 14 days of your Section 1(2) notice, you can only build the wall wholly on your own land, at your own expense - not astride the boundary. This isn't a dead end; it's simply a different, still-available route.
Yes. Section 1(5) lets you build a wall wholly on your own land, right up to the boundary, without needing consent. You still need to serve one month's notice, but your neighbour can't block it the way they can an astride wall under Section 1(2).
Yes, but only if you're building wholly on your own land under Section 1(4) or 1(5) - this right doesn't apply to an astride wall. Section 1(6) lets you place necessary projecting footings under the neighbour's land, but only in the window starting one month after your notice was served and ending twelve months after that.
Yes, where you're building wholly on your own land under Section 1(4) or 1(5). Section 1(7) requires you to compensate your neighbour for any damage caused by building the wall itself, or by placing projecting footings under Section 1(6).
Section 1 applies where the land on both sides of the boundary is either unbuilt on at the line of junction, or only has a basic boundary wall there already - not a party fence wall or the external wall of a building. If there's already a proper party wall or building on the boundary, you're likely looking at Section 2 instead, not Section 1.
Every boundary is different. Rather than guess which route applies to your wall, describe your actual project to the Notice Checker and get an immediate, plain-English indication of what applies.
Try the Notice CheckerThis page is general information about the Party Wall etc. Act 1996, not professional advice about your specific project. Whether a notice is required, and what it must contain, should always be confirmed directly with a qualified Party Wall Surveyor before any works begin or any notice is served.