New builds and warranties
A steel lintel in a new porch has no galvanising the surveyor could see and rust is starting. What corrosion protection is missing from that lintel?
The missing corrosion protection is galvanising on the steel lintel. No galvanising was visible, and rust is already starting on a lintel in a new porch. Bare steel in an outer wall will go on corroding once rust has begun. The survey has recorded the missing coating and the early rust. It has not measured how far the rust has eaten, and it has not opened a warranty claim. NHBC describes Buildmark as a 10-year warranty and insurance product. The survey does not open a claim.
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?
Galvanising is the zinc layer that protects a steel lintel while the wall weathers. A new porch lintel with no coating the surveyor could see, and with rust already on it, is a materials defect, not a scuff in the paint. Covering the colour later would hide the stain and would not put back a coating that was not there. The survey did not cut the steel and did not measure a remaining thickness. It recorded the surface it could see.
Raise the rusting lintel with the developer as a building defect, not as chipped decoration. Ask the solicitor how Buildmark sits against it. NHBC describes Buildmark as a 10-year warranty and insurance product. The survey does not open a claim, and a sentence in the report is not that claim. Do not let the item be closed by paint alone. Ask, in writing, what protection the lintel will actually be given.
What should you ask your surveyor?
- Was any galvanising visible on the porch lintel?
- Is rust already starting on that bare steel?
- Has the survey left any Buildmark claim unopened?
What are the typical next steps?
- Treat the missing galvanising as the corrosion protection that is absent.
- Raise the rusting lintel with the developer as a building defect.
- Do not treat the survey as the opening of a Buildmark claim.
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 lintel is painted next week, has the galvanising been provided?
No. Paint is not galvanising. The surveyor could see no galvanising, and rust had already started. A later coat may hide the colour. It does not replace the missing zinc protection, and it does not become a test of the steel. NHBC describes Buildmark as a 10-year warranty and insurance product. The survey does not open a claim.
Does rust on day one mean the porch is unsafe to stand under?
The survey has not said that. It has said the galvanising was not visible and rust is starting. That is a corrosion note on a new lintel, not a calculated structural failure. Nobody has measured the remaining steel. Do not ignore it because the porch is still standing, and do not invent a collapse the report has not described.