Changed your design mid-build? Swapped to deeper foundations, added steel into the party wall, or decided to raise the flank wall after all? If the scope of your works changes in a way that brings in new rights under the Party Wall etc. Act 1996 (or materially alters what you originally notified), you’re duty-bound to serve fresh Party Wall notice(s) that match the revised works—even if construction has already begun.
Below is a clear, no-nonsense guide to what happens next, what your neighbour can do, and how to keep your programme moving with minimal pain.
When a new notice is required
You must re-notify if the variation means you will now:
- Cut into, raise, underpin or otherwise work on a party structure (Section 2) where this wasn’t in the first notice;
- Excavate within 3m/6m to a lower level than your neighbour’s foundations (Section 6) and that wasn’t previously covered;
- Build on/astride the boundary (Section 1) where the original proposal didn’t include that; or
- Materially change the manner, depth or structural effect of the previously-notified works (e.g., switching from shallow trenches to piled foundations; adding new steels into the party wall; changing the line of junction strategy).
If in doubt, assume the safer route: serve a new notice that accurately reflects the revised drawings and method.
Can works continue while you re-notify?
Practically, you should pause any new “notifiable” elements until the notice period has run or the neighbour formally waives it in writing. Continuing with notifiable work without proper notice risks an injunction, delay, and extra cost. Non-notifiable parts of the project can often continue, but speak to your party wall surveyor so you don’t stray back into notifiable territory by accident.
Your neighbour’s rights after you re-serve
Even if your Adjoining Owner previously consented, the new notice resets their options. They can:
- Consent again to the revised works;
- Dissent and appoint an Agreed Surveyor (one impartial surveyor for both owners); or
- Dissent and appoint their own surveyor, triggering the two-surveyor route.
That means a neighbour who originally consented can now switch to dissent if the changes increase risk or impact. That’s normal—and the Act is designed for exactly this scenario.
Will a new Party Wall Award be required?
If there’s a dissent (or you already had surveyors involved), the surveyor(s) will likely need to issue a further award (or a variation award) covering:
- The revised scope and drawings;
- Updated time and manner conditions for the specific works (e.g., sequence of excavation, hand-tooling for beam pockets, temporary supports);
- Any temporary protection and access arrangements;
- Costs/fees allocation arising from the variation; and
- Any other matters incidental to the revised dispute.
Think of it as regularising the new plan—so everyone knows what’s happening, when, and how.
Fees and who pays
Generally, the Building Owner funds the reasonable costs of administering the Act (including the Adjoining Owner’s surveyor if appointed). When changes occur after start on site, expect:
- Additional surveyor time to review revisions and issue a new/variation award;
- Possible engineering input if the change alters risk;
- Programme impacts—which you can minimise by notifying early and providing clear drawings/method statements.
The quicker you formalise the change, the cheaper and smoother it is for everyone.
Practical tips to keep momentum
- Notify early. As soon as the design changes, tell your surveyor. Don’t let site run ahead of the paperwork.
- Be specific. Provide marked-up drawings, sections, and a brief method statement for the new elements.
- Offer sensible mitigations. Staging excavations, using hand tools for wall chases, or alternative temporary works often reassures neighbours and speeds agreement.
- Keep dialogue open. A short call between surveyors (or a courteous note from you) can prevent misunderstandings and preserve goodwill.
Common pitfalls to avoid
- “It’s only a small tweak.” Small tweaks can change the legal category of work. If it affects a party structure, the boundary, or foundation depths, it’s not a tweak under the Act.
- Assuming old consent covers new risks. It doesn’t. New notice, new choice.
- Waiting until the neighbour complains. By then you may face an injunction. Get ahead of it.
Bottom line
Changing course mid-project is normal. The Party Wall Act expects it and provides a clean mechanism: serve a new, accurate notice and, where required, secure a fresh or varied award before pressing on with the newly notifiable parts. Do that promptly and you’ll protect your programme, your relationship with your neighbour, and your budget.
Need the new notice (and award) turned around quickly?
We’ll review your revised drawings, confirm exactly what must be re-noticed, serve compliant notices, and—if there’s a dissent—agree the variation award fast and fairly.
Simple Survey — RICS Party Wall Surveyors
- Party Wall Notice service: £25 per adjoining ownership (multi-notice bundles discounted)
- Agreed Surveyor administration: typically £300 fixed fee (depends on complexity/number of owners)
- Two-surveyor route (we act for the Building Owner): fixed-fee proposals from £325 for our side (we work to keep your neighbour’s surveyor’s hourly fees reasonable and contained)
Email team@simplesurvey.co.uk for a quick, clear plan to regularise your change and keep your build on track.