Age and type of house
The 1930s bay has a small flat roof that ponds, and the cavity walls are dry. Why should the bay roof be read on its own?
The bay roof should be read on its own because it is a small flat roof that ponds, and dry cavity walls do not clear that ponding. Water sitting on the flat top is a roof finding at the bay. The main cavities being dry says something about those walls on the day. It does not inspect the flat covering, the outlets or the abutment where the bay meets the house. The survey has not decided the flat top is sound merely because the cavities were dry.
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 1930s bay often carries a little flat roof, or a felted top, over the projecting windows. That covering is a different element from the cavity brick of the main house. Ponding means water is not leaving. It can sit at joints and at the junction with the wall above the bay. Dry cavities elsewhere are easy to misuse as a general pass. They are a wall observation in another place. Keep the bay roof in the roof section.
Ask a roofer to comment on this flat top, the outlets and the upstand, if you need a repair view the survey has not priced and has not designed. Tell your solicitor the bay roof is a separate defect note from the dry cavities. Do not let a buyer or a seller merge them into one comfortable sentence. The home survey has recorded ponding on that small roof. It has not tested the covering by noticing dry walls.
What should you ask your surveyor?
- Where was the water ponding, and how was it supposed to drain?
- Did you see the abutment between the flat top and the main wall?
- Are the dry cavities recorded separately from this bay roof?
What are the typical next steps?
- Read the bay's flat roof as its own element.
- Do not clear the ponding because the cavity walls were dry.
- Ask a roofer about the flat top, the outlets and the upstand.
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 bay ceiling is unstained, can the ponding be ignored?
No. An unstained ceiling means water had not marked that ceiling on the day. Ponding on the flat top can still be attacking the covering and the joints. The survey has not cleared the bay roof. Dry plaster in the bay does not clear the flat covering.
Does a dry cavity prove the bay was built with a cavity too?
No. The dry cavities are the walls that were checked. The bay has its own flat roof. The survey has not used the wall result to describe that roof as sound. Those dry walls do not redescribe the ponding roof.