Under Section 11(11) of the Party Wall etc. Act 1996, if an Adjoining Owner later makes use of work that was originally built and paid for solely by the Building Owner, the Adjoining Owner must pay a due (fair) proportion of the cost of that work. Crucially, the Act values that contribution at current-day prices—i.e., what it would cost at the time of subsequent use, not what it cost years ago.
Statutory anchor (s.11(11)): where later use is made of work paid for by one owner, the other pays a due proportion, calculated by reference to the cost if done at the time of that later use.
When does a “making use” (often called enclosure) payment apply?
- When the second owner’s new works rely upon, tie into, or build off a wall or structure previously constructed and funded by the neighbour.
- This commonly arises with rear/side extensions, loft conversions (e.g., steel bearings or raised party walls), and basements.
Important nuance: An enclosure payment can arise whether the earlier wall was:
- built astride the boundary as a party wall, or
- built up to the boundary wholly on the builder’s land (the second owner later “encloses” upon it).
In both cases, once the second owner makes use of that wall, a contribution becomes due.
How is the payment worked out?
Surveyors will assess a fair share (often thought of as ~50%, but it’s not automatically half: it’s what’s reasonable in the circumstances) of the current-day cost of the relevant wall/element being “made use of”. Typical cost heads include:
- Excavation for foundations supporting the wall/element
- Removal and cart-away of spoil
- Concrete to form foundations
- Masonry structure (brick/block), including ties, insulation, DPC/DPM, cavity trays, lintels, bearings, and associated labour
- Any structural steel or reinforcement integral to that wall/element where the subsequent works derive support/benefit
The contribution usually excludes finishes and items that are not integral to the structure being made use of.
Where is it recorded?
The amount (or the method of calculating it) is typically set out in the Party Wall Award for the second owner’s project, so both sides have a clear, enforceable record. If timing or exact sums aren’t yet fixed, the Award may include a mechanism for later valuation at the point of use.
Practical example
- Owner A built a flank wall for their rear extension five years ago at their sole cost.
- Owner B now proposes a matching rear extension and ties into/uses that existing wall for support and enclosure.
- The surveyors value the relevant wall today at, say, £12,000.
- After considering scope of reliance (full vs partial height/length, structural benefit) and what’s reasonable, the due proportion might be set at, for example, 50% = £6,000 (illustrative only—the percentage is case-specific).
Common misconceptions
- “It’s always 50%.” Not necessarily. The Act requires a due proportion, reflecting benefit and reliance, not a fixed split.
- “It only applies to party walls astride the boundary.” Incorrect. Later enclosure on a wall built up to the line (on one owner’s land) can also trigger payment when use is made.
- “We use the original invoice values.” No—the Act points to current-day cost at the time of subsequent use.
Why it’s actually a saving
For the second builder, using an existing compliant wall typically means:
- Lower build cost (less excavation, concrete, masonry to build from scratch)
- Simpler site logistics
- Potentially more internal width where design permits
The enclosure payment is, in effect, paying your fair share of a wall you no longer have to build.
Need a clean, fair valuation—or wording for your Award?
Email team@simplesurvey.co.uk. Simple Survey are the lowest-cost party wall surveyors across England & Wales. We’ll:
- confirm whether Section 11(11) applies,
- agree a due proportion on current-day costs, and
- draft clear Award wording so both parties know exactly where they stand.