Do I need a party wall agreement for a loft conversion?
Last updated: 19 July 2026
If you live in a terraced or semi-detached house, almost certainly yes — and it's far less scary than it sounds. Here's the whole picture in five minutes.
Why lofts trigger the Act
Nearly every loft conversion rests new steel beams in the wall between you and next door. That wall is a party wall — you each own the bit on your side, and the Act protects you both when either of you works on it. Cutting into it to bear a beam is exactly the kind of work section 2 of the Party Wall etc. Act 1996 covers, and section 2 work needs a party structure notice served on your neighbour at least 2 months before you start.
Raising the party wall for a dormer, inserting a damp-proof course, or removing a chimney breast from the shared wall are section 2 works too. A detached house is the main exception — no shared wall, and unless you're digging near next door's foundations, usually no notice.
"Agreement" is the wrong word — it starts with a notice
You don't need your neighbour's permission to convert your loft. You need to notify them, and they then have three ways to respond. Most consent in writing, and that's the end of it — no surveyors, no cost beyond the stamp.
The clocks that matter
- 2 months — the minimum notice before starting section 2 work (earlier only with your neighbour's written agreement).
- 14 days — your neighbour's window to respond. Silence counts as dissent under section 5, and a dispute formally exists — that's normal and manageable, not a catastrophe.
- 12 months — how long a served notice stays valid. Work must begin within it, or you serve again.
What it costs
Serving the notice yourself is free. If your neighbour consents, that's usually the total. If they dissent, surveyors are appointed and a loft typically runs around £1,575 with a single agreed surveyor — and the building owner (you) normally pays both sides' reasonable fees. The full numbers are on our costs page.
The mistakes that invalidate notices
Most DIY notices fail on paperwork, not law. The usual suspects:
- Not naming all owners — couples: both names; serving the tenant instead of the owner; missing the freeholder of a flat.
- A start date inside the 2-month notice period.
- Unsigned, undated, or citing the wrong section of the Act.
Where to start
The free checker tells you in about 90 seconds whether your loft needs a notice and which one. If it does, the £39 pack gives you ready-to-serve notices based on the government's official templates, your neighbour's reply forms, and a serving checklist that catches the mistakes above.