When projects get bigger, the Party Wall etc. Act 1996 expects more structure, more safeguards—and, usually, more professionals involved.
At Simple Survey, we keep the process simple and clear, even on high-stakes schemes. Below we outline the types of works the Act typically treats as “major”, why they carry higher risk, and how to navigate the likely outcomes (including dissent, two-surveyor appointments, advising engineers, Security for Expenses, and movement monitoring).
What the Act considers “major” and why
1) Basement conversions
Basements almost always trigger Section 6 (adjacent excavation) and often underpinning. You’re excavating close to neighbouring foundations and altering how loads transfer—so risk, perception of risk, and complexity all spike. Adjoining Owners frequently dissent to Notices here (perfectly reasonable), leading to either an Agreed Surveyor or two-surveyor route. Expect requests for:
- Advising engineer input to review sequencing, temporary works and waterproofing interfaces.
- Security for Expenses (s.12) to protect against non-completion or foreseeable making-good.
- Movement/condition monitoring (crack gauges, level pins, vibration thresholds) to prove stability through the works.
2) Deep excavations
Lightwells, piled foundations and deep pads are classic Section 6 cases. Even if the footprint is modest, depth and proximity drive risk. Anticipate engineer-to-engineer dialogue on temporary works and excavation staging, and a heightened likelihood of dissent leading to formal Awards.
3) Extensive works to party walls or party structures
Large-scale alterations under Section 2—substantial chimney breast removals, major load transfers (lofts with steel frames), thickening/raising works—can materially affect a shared structure. Awards typically lock in controlled methods (e.g., non-percussive/hand tools at the party wall to reduce vibration) and set tolerances, sequencing, and interface details to protect both sides.
4) Underpinning
Underpinning is a structural risk-transfer exercise; it often appears in basement schemes and sometimes in extensions with deeper foundations than the neighbour’s. Under Section 2 and Section 6, surveyors will expect engineered method statements, temporary works, and, in many cases, Security for Expenses given the consequence of incomplete or poorly sequenced works.
Why risk drives procedure
When the perceived risk goes up, Adjoining Owners are more likely to dissent to a Notice. That isn’t “anti-build”—it’s simply the Act doing its job: moving matters into a statutory dispute-resolution track so independent surveyor(s) can test the design, prescribe method and timing, and set protections in a binding Party Wall Award.
On major works, it’s also common to see:
- Two-surveyor route (each owner appoints their own surveyor) for added independence.
- Third surveyor named (as a safety valve) if two surveyors can’t agree specific points.
- Advising engineer engaged by the surveyor(s) to review the technical risk.
- Monitoring regimes included in the Award (e.g., trigger levels, stop-work thresholds, reporting cycles).
- Security for Expenses sums agreed/awarded, held and released in stages as risk reduces.
Handled well, these controls de-risk your build and reassure neighbours, keeping construction moving.
How Simple Survey keeps “major” projects smooth
Front-load clarity
We confirm what’s notifiable, which sections apply (1, 2, 6), and what drawings/calcs are needed (Section 6 requires plans/sections with depths).
Engineer-to-engineer dialogue
Where an advising engineer is appropriate, we organise sensible, focused reviews—aimed at buildable refinements, not “design by committee.”
Proportionate protections
Awards that mandate hand tools at the shared fabric, define vibration limits, set access protocols (Section 8) and practical working windows—enough control to protect, not so much that your contractor can’t build.
Security for Expenses—fair and workable
We’ll help owners agree a realistic sum (or determine it where agreement isn’t possible), with clear release points linked to programme milestones.
Neighbour communication
Major schemes benefit from calm, consistent explanation. We keep Adjoining Owners informed without inflaming, reducing the chance of spiralling fees.
Pricing that stays predictable—even on big jobs
- 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)
You’ll get a fixed, written proposal before we start—no meter-running surprises.
Ready to de-risk your “major” works?
If you’re planning a basement conversion, deep excavation/lightwell, extensive works to a party wall/structure, or underpinning, bring us in early. We’ll set the right notices, the right protections, and the right professional inputs—so you can build confidently and compliantly.
Email: team@simplesurvey.co.uk
Attach any drawings or engineer’s notes you have—even preliminary ones. We’ll confirm what’s notifiable, serve valid Notices, and steer you to a robust, buildable Party Wall Award at market-leading fixed fees.