Party wall and flats: party structures, floors and leaseholders

Flats are where people are most often caught out by the Party Wall Act. Many assume it only applies to houses, or that the freeholder’s licence covers everything. Neither is right. In a converted house or purpose-built block you may have neighbours on both sides, above and below, plus a freeholder, and each of them may be an “owner” entitled to notice.

How the Act applies to flats

Section 20 defines a party structure as “a party wall and also a floor partition or other structure separating buildings or parts of buildings approached solely by separate staircases or separate entrances”. Self-contained flats almost always meet that test, so the floor between a ground-floor and first-floor flat, and the walls between side-by-side flats, are party structures.

The section 2 rights then apply to them exactly as they do to a party wall between houses. Typical flat works that are notifiable include:

• Cutting into a separating wall or floor (s.2(2)(f)), for example forming beam pockets or cutting into floor joists that are shared structure.
• Removing a chimney breast from a party wall (s.2(2)(g)). See chimney breast removal.
• Thickening or underpinning a party structure (s.2(2)(a)), including some heavy acoustic upgrades fixed into the structure.
• Raising a party wall for a roof extension or new storey (s.2(2)(a)).
• Exposing a party structure previously enclosed (s.2(2)(n)), subject to adequate weathering.

Not everything is notifiable. Replacing floor finishes, re-plastering, fitting kitchens, minor fixings such as shelves, and minor chases for sockets and wiring are not notifiable. Likewise, roof works such as adding rooflights may not need notice at all: only work that goes into the party wall or party structure itself is relevant. The question is whether you are doing something the Act lists to the party structure itself.

Who counts as an owner

Under section 20 “owner” includes a person in receipt of, or entitled to receive, rents or profits of the land, and a person in possession other than as a tenant from year to year or for a lesser term. In practice that means:

• The freeholder of the building (including a residents’ management company that owns the freehold).
• Any long leaseholder of an affected flat, generally a lease of more than a year.
• Someone who has contracted to buy an interest in the flat.

A short-term tenant on an assured shorthold tenancy is an occupier, not an owner, although they are an “adjoining occupier” with rights to compensation under section 7 and notice of entry under section 8. See landlords, tenants and councils.

As a leaseholder doing work, you are the “building owner”. If you are a leaseholder whose neighbour is doing work, both you and your freeholder may be adjoining owners, and either can consent or dissent.

The lease and the Act work side by side

• The lease controls what you are allowed to alter at all. Most leases prohibit structural alterations without the landlord’s licence, and many reserve the structure, including floors, joists and main walls, to the freeholder.
• The Act controls how notifiable work is done relative to the adjoining owners, and resolves disputes about it.

A licence for alterations from the freeholder does not replace party wall notices to the other leaseholders, and a Party Wall Award does not give you a right your lease forbids. Get both in place. If the freeholder owns the structure being cut into, the freeholder is also an adjoining owner for that work.

Vertical neighbours: floors and ceilings

Party structures between flats run horizontally as well as vertically. Common issues are:

• Downstairs ceilings. Work to joists or floor voids above can crack the ceiling below. Schedules of Condition of the flat below are essential.
• Sound insulation. Replacing carpet with hard flooring is a lease matter, not a party wall matter, but fixing acoustic systems into shared joists may be.
• Services. Pipes and cables for the flat below often run in the floor void; the Award can deal with protection and reinstatement.
• Fire separation. Separating floors provide fire separation. Building control will check, and surveyors will want it reinstated.

Roof and loft extensions on flats

A top-floor leaseholder extending into the roof, or a freeholder adding a storey, will normally need notices to the adjoining houses (raising party walls), to the flats below (cutting into party structures), and possibly section 6 notices if new foundations are needed for steel columns. These projects usually involve several adjoining owners and benefit from surveyors on all sides.

Common problems

• Missing owners. Serving the freeholder but not the leaseholders, or vice versa. Check the title register for each flat at HM Land Registry.
• Assuming the managing agent can consent. A managing agent can only consent on behalf of the freeholder if properly authorised.
• Lease breaches. Starting work with party wall consent but no licence can lead to forfeiture proceedings under the lease.
• Overlooking the flat below because it is not “next door”.

Checklist for flat owners planning work

• Read your lease and apply for a licence for alterations early.
• Identify every owner: freeholder, leaseholders on each side, above and below.
• Check which items of work affect a party structure.
• Serve section 3 notices two months ahead (and section 6 if relevant).
• Arrange Schedules of Condition of adjoining flats, including ceilings below.
• Get building regulations approval for structural and fire-separation work.

Worked example (illustrative)

Illustrative only. Not a real case.

A leaseholder of a first-floor flat in a converted Victorian house wants to remove the wall between kitchen and living room and insert a steel beam bearing into the party wall with the house next door. The freeholder is a company owned by the two leaseholders. Notices are needed for the owners of the house next door (cutting into the party wall for the bearing) and for the freeholder and the ground-floor leaseholder (cutting into the floor structure to fix the new posts). The leaseholder also obtains a licence for alterations under the lease. Next door consents with a Schedule of Condition; the ground-floor leaseholder dissents and appoints a surveyor, who agrees a method to protect their ceiling. One Award is made for that dispute and the work proceeds.

At a glance

Costs with us

Domestic extensions and loft conversions. Fixed fees, invoiced on completion; we take enquiries only, with no online payment. If your neighbour appoints their own surveyor, the building owner normally pays that surveyor’s reasonable fees as well (s.10(13)), and those are set by that surveyor, not by us.

Practical tips for flat owners receiving notice

• Check whether you, your freeholder, or both have been served. If only one has, point it out.
• If your ceiling is below the works, ask for it to be recorded closely in the Schedule of Condition.
• Tell your own tenants, if you let the flat, and arrange access.
• Remember that the building owner normally pays your surveyor’s reasonable fees if you appoint one (s.10(13)), and that you can ask for the cost of making good to be paid to you instead of repairs being done (s.11(8)).

Sources and further reading

• Party Wall etc. Act 1996, section 2: Repair etc. of party wall: rights of owner (legislation.gov.uk)
• Party Wall etc. Act 1996, section 3: Party structure notices (legislation.gov.uk)
• Party Wall etc. Act 1996, section 7: Compensation etc. (legislation.gov.uk)
• Party Wall etc. Act 1996, section 8: Rights of entry (legislation.gov.uk)
• Party Wall etc. Act 1996, section 10: Resolution of disputes (legislation.gov.uk)
• Party Wall etc. Act 1996, section 20: Interpretation (legislation.gov.uk)
• The Party Wall etc. Act 1996: explanatory booklet (GOV.UK)

This guide is general information on the law in England and Wales, written from our surveyors’ practical experience. It is not legal advice; for a specific dispute, take advice on your own facts.

Sources: Party Wall etc. Act 1996 (legislation.gov.uk) · The Party Wall etc. Act 1996: explanatory booklet (GOV.UK). Last reviewed 27 October 2026. General guidance on the law in England and Wales, not legal advice.