Planning an extension is exciting—more space, more value, better living. If your works interact with a neighbour’s land or shared structures, parts of your build will fall under the Party Wall etc. Act 1996. Here’s a clear, practical guide to keep you compliant, neighbourly, and on-programme.
1) When the Act applies to extensions
Adjacent Excavation (Section 6)
If you’ll excavate within 3–6 metres of a neighbouring structure and your excavation will go deeper than their foundations, you must serve a Section 6 Notice. This typically captures:
- New strip/raft foundations for front, rear or side extensions
- Lightwells, underpinning, deep pads, piled solutions
Tip: A Section 6 notice must include drawings/sections showing location and depth. Missing plans = invalid notice.
Building on/near the boundary (Section 1)
If your flank wall will be built up to the boundary line (s.1(5)) or astride the boundary (s.1(2)), serve a Section 1 Notice.
- Astride the boundary requires neighbour consent; without it, you build up to the line on your own land.
Works to a party wall/structure (Section 2)
Where your scheme includes works directly to a party wall/party fence wall/party structure (e.g., tying in, flashing, raising parapets), serve a Section 2 (Party Structure) Notice.
2) Serve valid notices—early
- Minimum lead-times:
- Section 1 & Section 6: serve ≥ 1 month before the notifiable works start
- Section 2: serve ≥ 2 months before the notifiable works start
- Response windows: 14 days for an initial response; if silent, a 10-day reminder follows to appoint a surveyor.
- Method of service: Serve in one of the valid ways (post, by hand, fixing to door, or email only with prior written consent). Wrong service = invalidity and delays.
3) Access rights to build your flank wall (Section 8)
Yes—the Act can grant access to the neighbour’s land where reasonably necessary to carry out notifiable works (e.g., building a flank wall up to the boundary). But access is not a free-for-all:
- It is governed by a Party Wall Award and limited to specific tasks, hours, and durations.
- Expect protective provisions: temporary fencing/hoarding, ground protection, safeguarding planting, making-good duties, indemnities, and a clear access programme.
- Refusal after access is awarded can be enforceable—so plan, communicate and keep the route tidy and safe.
4) Foundation trenches: keep them safe and short-open
Open trenches are a classic risk to your neighbour’s ground and structure. A sensible rule of thumb:
- Do not leave open or unsupported trenches any longer than necessary.
- Aim to pour within ~24–48 hours (project- and soil-dependent) or shore/bracing must be installed.
- Coordinate concrete delivery and inspection slots in advance so you don’t miss the safe window.
5) Make the Award “known” on site
Your Party Wall Award will set out time and manner of the works and risk controls. It often includes:
- Hand tools / non-percussive methods at the party wall face (reduces vibration and cracking)
- Dust and soot control (e.g., covering open vents/flues before works)
- Access protocols, hours, temporary works, debris management
- Tie-in/weatherproofing obligations during envelope alterations
Action: Brief your contractor and subcontractors on the Award. Pin the Award + referenced drawings in the site office. If the build method or drawings change, tell the surveyor(s) before proceeding—material deviations may require supplemental agreement.
6) If damage happens—use the Act’s quick remedy
- Report issues early to the surveyor(s) and neighbour; photograph and video everything.
- You can make good via your contractor or fund the neighbour’s contractor (with reasonable quotes).
- If you can’t agree, the surveyor(s) will determine liability and cost via a further/variation Award.
- Awards are enforceable—proactive engagement is faster and cheaper than stalemate.
7) Pre-start checklist for extensions
- Final architect/engineer drawings frozen; Building Control route set
- All relevant notices validly served (Sections 1/2/6 as applicable)
- Award served (or in agreed-surveyor draft) with final drawings attached
- Access plan agreed (routes, timings, ground protection, reinstatement)
- Pour logistics in place for foundations (delivery slots, inspection windows)
- Contractor briefing held; Award pinned on site
- Neighbour update channel agreed (email/WhatsApp for short notices and weather windows)
8) Common pitfalls (and how to avoid them)
- Invalid notices (wrong owner, wrong section, missing detail) → Have a surveyor serve them; DIY errors reset the clock.
- Late service → You can’t compress statutory periods without neighbour agreement. Serve early.
- Ignoring the Award → Expect complaints, extra surveyor time, and potential injunction risks.
- Leaving trenches open → Programme concrete or shoring—don’t leave stability to luck.
- Design drift after Award → Flag changes promptly to avoid non-compliance.
Simple Survey — clear, fixed pricing (nationwide)
Straightforward fees
- Party Wall Notice service: £25 per adjoining ownership (multi-notice bundles discounted)
- Act administration as Agreed Surveyor (single surveyor): typically £300 fixed-fee (depends on complexity and number of notices/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.
Why Simple Survey
- RICS-qualified building surveyors (real building-pathology expertise)
- Nationwide, fixed-fee model—no surprises
- Calm, neighbour-first administration that keeps projects moving
Affordable Expertise
Planning an extension that triggers the Party Wall Act?
Email your drawings for a free notifiability check and a fixed-fee plan. We’ll serve valid notices, agree a workable Award, and brief your contractor so your build stays safe, lawful, and on track.
Our fees are always fixed. We’re nationwide. We’re both experienced and qualified.