Party walls and boundaries
A neighbour's extension means your gutter now discharges onto their new flat roof. Can the survey decide who must move that gutter?
No. The survey cannot decide who must move that gutter. It can record that your gutter now discharges onto the neighbour's new flat roof, which is a change in where the rain goes. Who has to move the gutter, alter the outlet or accept the water is a boundary and neighbour question, not a condition finding. The inspection has not applied the party wall rules, has not appointed anyone, and has not split the cost or the duty. GOV.UK explains party walls and related work. A home survey does not issue that decision.
Last reviewed 24 October 2026. Written for buyers in England and Wales unless this answer says otherwise. No named surveyor has signed this page. It is general guidance, not a report on your house, and not legal advice.
What is the fuller explanation?
An extension next door can leave an old gutter pointing at a roof that did not used to be there. The water now lands on their flat roof instead of being carried to a downpipe on your side. That is worth describing, because a flat roof is a poor place to receive a neighbour's gutter, and because stains or ponding may follow. Description is not liability. The surveyor was not instructed as a party wall surveyor and did not hear both owners.
Put the discharge in front of your solicitor with the deeds and any permission for the extension. GOV.UK's party wall guidance is about notices and certain work, not about a home survey declaring a winner. Ask the surveyor only what was seen: where the gutter discharges, and whether the flat roof or your eaves look distressed. Leave who must move the gutter to the legal side of the purchase. Do not treat a condition sentence as an order to relocate it.
What should you ask your surveyor?
- Where does the gutter discharge now, relative to the neighbour's flat roof?
- Did you see staining or ponding, or only the altered fall of the water?
- Are you deciding liability, or only recording the discharge?
What are the typical next steps?
- Record that the gutter discharges onto the neighbour's new flat roof.
- Ask the solicitor who must deal with that discharge.
- Do not treat the survey as a decision on moving the gutter.
Costs vary with the building and with who you instruct. Where this page does not cite a published figure, ask the surveyor, a relevant specialist, or your solicitor for a written quote. Do not treat a forum average as the price.
Also asked about this
If your gutter is old, does that prove you must move it?
No. Age is a condition fact about the gutter. It does not decide liability for a discharge onto a roof the neighbour has built. The survey can say the gutter is old and where it empties. It cannot say who must move it.
Can the survey require the neighbour to alter the flat roof?
No. The neighbour is not the client, and the survey does not order work on their extension. It records that your gutter now throws water onto that roof. Any change to their roof or your gutter is outside the inspection.