Party Wall Notices

A party wall notice guide for homeowners doing works to their homes including extensions, loft conversions and new builds

If you’re planning an extension or loft conversion, understanding when a party wall notice is required can save time, cost, and neighbour disputes. This guide explains when a party wall notice is needed, why the depth of foundations matters (the 3-metre and 6-metre rules), how to avoid the common delays and disputes, and what you can realistically do yourself.

Quick summary

• What it is: A legal notice under the Party Wall etc. Act 1996 telling neighbours about works that affect a shared wall/boundary or involve excavations close to their foundations.

• When it’s needed : works to a party wall, building on the line of junction, and excavations within 3m (or sometimes 6m) if the new excavation goes deeper than the neighbour’s foundations (Section 6).

• Who pays: normally the building owner (the person doing the work) pays the surveyors’ fees and reasonable costs.

What is a party wall notice?

A party wall notice is a formal written notice from the building owner to the adjoining owner explaining proposed works that might affect a shared wall, boundary or the foundations of a neighbour’s building. It’s not the same as planning permission or building control — it’s a separate legal process that protects both properties and sets out how the work will be done (or that a surveyor will decide). The Act applies across England & Wales.

Exactly when you need to serve one

There are three common triggers that matter to most homeowners:

1. Works to a party wall / party structure (Section 2 / Section 3)
   Examples: cutting into a shared wall to insert a steel for a loft conversion, raising or underpinning a party wall, inserting a damp-proof course across a party wall. This generally requires two months’ notice.
2. Building on the line of junction (Section 1)
   Example: building a new wall on the boundary line or projecting foundations up to the line of junction. This type of notice normally requires one month’s notice. 
3. Adjacent excavations — the 3-metre and 6-metre rules (Section 6)
   The Act applies when both of the following are true:
   • your excavation will be within 3 metres of any part of a neighbouring building or structure and will go deeper than the bottom (base) of the neighbour’s foundations; or
   • your excavation is between 3 and 6 metres away but will meet a plane drawn downwards at 45° from the bottom of the neighbour’s foundations (so a shallower excavation further away can still be caught).

In short: it’s about proximity + relative depth — not proximity alone. That’s why a new basement, deep strip foundations, piling works or underpinned extensions are often caught by Section 6.

Why foundation depth matters — and how to prove it

You often won’t know the exact depth of your neighbour’s foundations just by looking. That’s why:

• experienced surveyors and structural engineers will make reasoned assumptions based on the age/type of the building;

or

• your team may carry out trial pits (small hand-dug test excavations) to expose and measure the neighbour’s foundation level before final design and notice — especially for basements, deep footings or tight boundaries. Trial pits are a common, practical way to remove doubt and avoid late changes. Finalising your foundation design before serving an excavation (Section 6) notice removes most of the risk of having to re-serve or amend notices later.

Serving a Party Wall Notice: Timing and Best Practice

• Party structure notices (work on a party wall): serve at least two months before you start.
• Line of junction & adjacent excavation notices: typically at least one month before start.
• Notices expire: a valid notice will lapse after 12 months if you haven’t started the relevant works, so don’t serve notices unnecessarily early — but don’t serve too late either. If the neighbour gives written assent you can proceed (but keep records). If they don’t reply, the Act treats that as dissent and the dispute-resolution process begins.

What happens after you serve notice

• The neighbour has 14 days to respond (they can consent, dissent, or suggest a counter-notice). If they dissent (or don’t reply), party wall surveyors will be appointed and a Party Wall Award (a legally binding schedule describing how the work will proceed and who pays what) will be prepared. Appointing surveyors is the normal route where there’s disagreement.

Costs and who pays

• Practical rule: the building owner (the person doing the work) typically pays the reasonable fees for the party wall process — this usually includes the adjoining owner’s surveyor fees where those are necessary.

Pros & cons

Pros

• Legally protects you and your neighbour; reduces risk of expensive damage claims later.
• Sets out method statements, working hours, access arrangements and a schedule of condition.
• A properly drafted Award makes it much easier to exchange contracts if you sell later.

Cons

• Time and cost
• If neighbours dissent, there may be a 4–12 week (or longer) delay while surveyors prepare an Award.
• Mistakes in notices (wrong wording, missing drawings) can invalidate them and cause delays.

What you can do yourself — and when to use a surveyor

You can do yourself

• You can prepare and serve your own notice using standard templates (the gov.uk booklet includes examples). If your neighbour is cooperative and the works are straightforward (e.g. minor internal works that are genuinely non-party), this can be faster and cheaper. GOV.UK+1

When to bring professionals in

• Any work involving excavations close to neighbours, basements, underpinning, piling, or cutting into party walls for structural steel — get a structural engineer and a party wall surveyor involved early. Finalise your foundation design before serving notices to avoid re-serving or disputes. Surveyors also prepare the schedule of condition to protect you and the neighbour and help resolve technical disagreements.

Practical checklist for homeowners (our recommended sequence)

1. Early conversation: tell your neighbour informally what you plan and show the drawings. (Neighbourliness avoids many problems.)
2. Structural design: commission your structural engineer and finalise foundation proposals — do this before serving Section 6 notices.
3. Assess Section 6 risk: if foundations are close, check whether the excavation will be deeper than the neighbour’s foundations or intersect the 45° plane from their foundation base. If uncertain, assume it may apply and seek professional advice.
4. Decide on DIY or surveyor-prepared notice: You could use gov.uk templates if you wish, or use an experienced party wall surveyor for anything technical or contentious.
5. Serve the notice with clear drawings & start date (allowing the statutory notice period).
6. If award required, let the surveyors prepare it — don’t start work until the Award is in place unless you have the neighbour’s signed consent.

Common pitfalls — and how to avoid them

• Serving too early or with incomplete drawings → notice may lapse or be defective. Finalise structural details first.
• Underestimating trial pits — without them you may guess neighbour foundation depth incorrectly; a late requirement for deeper foundation can force a re-notice. Commission trial pits or agree a methodology with the surveyor/engineer.
• Starting before the Award → can be blocked, expose you to liability and make disputes worse. Don’t start without consent or a final Award.

Our approach

We advise clients to finalise foundation design with their structural engineer before serving Section 6 notices. We also work with reputable, independent party wall surveyors who prepare robust notices and Awards, negotiate on your behalf, and produce a schedule of condition to protect you. That combined approach reduces delays, avoids unnecessary cost and keeps projects on schedule.

Contact us today if you wish to discuss your project.