Damp Proofing Injection on a Party Wall: Do I Need a Surveyor?
Often, yes. Inserting a damp proof course into a party wall is listed work under Section 2 of the Party Wall etc. Act 1996, so a notice is normally required. Whether a surveyor is then needed depends on your neighbour's response.
What the Act says about damp proofing
Inserting a damp proof course in a party wall is one of the kinds of work to an existing party wall for which notice must be given. Chemical injection involves drilling into the wall, and it may affect the neighbour's side of the same wall.
Who needs a surveyor
You do not have to appoint a surveyor when you serve the notice. A surveyor is needed only if a dispute arises. That happens if your neighbour dissents or does not reply within 14 days. If they consent in writing, no award is needed, though consent has limits and should be recorded clearly.
Grey areas
Some jobs described as damp proofing do not affect the party wall, for example a tanking membrane on your own side, or surface treatment that does not alter the structure. Where the work falls between clearly notifiable and clearly not, it is uncertain, so take professional advice.
What to ask your contractor
Ask whether they propose to drill the party wall itself or only your own walls. Ask whether the treatment could push moisture or salts across to the neighbour's side. A reputable contractor should be able to explain this in writing.
Timing
Serve notice at least two months before the work begins. Do not let the contractor start on a booked date if the notice period has not run.
Damp work also raises a practical point. Injected treatments should be carried out to a stated method, and you should keep the guarantee and specification. If the neighbour later reports damp on their side, you will want a clear record of what was done and when.
Frequently asked questions
Is a damp survey covered by the Act?
A survey that only looks and does not alter the wall is not work to the wall. Drilling or coring is different.
Does my neighbour need to pay?
No. The building owner normally pays reasonable costs where the work is for their benefit.
Can I skip the notice if the wall is only slightly damp?
No. The size of the damp problem does not change the rule.
Related guides
- Understanding Section 2 of the Party Wall Act: Existing Party Walls
- Party Wall Notices, Awards, and Agreements Explained
- When Do You Need a Party Wall Surveyor?
- Schedule of Condition: Why You Need One Before Building
Last updated: . This page is general information about the Party Wall etc. Act 1996 (England and Wales). It is not legal advice. Every property and dispute is different, so take advice from a party wall surveyor or a solicitor before you act.