Listed buildings and conservation areas
A plastic casement has been cut into a stone mullion window on a listed cottage. Can the survey regularise that opening?
No. The survey cannot regularise a plastic casement cut into a stone mullion on a listed cottage. It can record the plastic frame, the cut stone and what has been lost of the mullion pattern. Regularising an opening is a consent process. Historic England explains that listing covers the whole building. The survey does not grant consent, and a condition note does not become listed building consent because the opening was photographed.
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?
A stone mullion window is part of the listed fabric, not a lining that can be swapped without record. Cutting a plastic casement into it changes the window and the stone around it. The survey can describe the plastic, the cut and the junction it could see. It cannot undo the opening, approve it, or file the paperwork that might regularise it. Those steps sit with the council and the solicitor, not in the inspection.
Ask the solicitor to search for listed building consent for the plastic casement, and to say what is missing if none is found. The survey does not grant consent and will not start that application. A specialist in listed windows can describe the stone and the plastic if you need a scheme later. Do not tell a lender the opening has been regularised by the home survey. It has not.
What should you ask your surveyor?
- Did you describe the plastic casement and the cut stone without regularising them?
- Have you left listed building consent with the solicitor and the council?
- What of the mullion pattern was still visible, and what had been cut away?
What are the typical next steps?
- Treat the plastic casement as recorded, not regularised.
- Ask the solicitor to search for listed building consent.
- Do not read the survey as consent for the altered mullion.
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 the plastic frame does not leak, is the alteration accepted?
No. A dry frame is a weather note about the day of the visit. It is not listed building consent. Historic England explains that listing covers the whole building, and the survey does not grant consent for the cut mullion.
Can the surveyor recommend a stone repair that counts as consent?
A repair comment would still be advice, not consent. The survey cannot regularise the opening. Consent, if it is needed and if it can be obtained, is a separate process the inspection has not carried out. Historic England explains that listing covers the whole building, which the survey does not regrade.