Damp and moisture meters
The soffit of a steel beam shows condensation and the wall below is dry. Why is that a cold-bridge note and not moisture from the ground?
It is a cold-bridge note because the wet face is the steel soffit, which chills room air until moisture drops out on the metal, and the wall below is dry. Moisture from the ground would show low on the masonry, and that wall was dry. The survey has recorded condensation on the beam. It has not called it rising damp, and it has not proved a leak from above. Steel carrying cold into a warm room is the mechanism that fits what was seen.
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 steel beam is a good conductor. Where it passes through a cold zone and its soffit is exposed in a heated room, the metal sits below the dew point and beads. That bead is on the soffit, not climbing the wall. A dry wall beneath argues against reading the bead as water drawn from the ground. The survey did not open the floor above the beam and did not test a damp-proof course that the pattern does not suggest. The pattern suggests a cold bridge.
Deal with the note as ventilation and surface temperature: how the room is heated and aired, and whether the soffit is insulated, which the survey has not designed. Tell the solicitor it is not a ground-moisture finding. Do not commission a chemical damp-proof treatment for a dry wall because a beam is sweating. If staining spreads into the wall later, that would be a different pattern and a reason to look again. It is not the pattern written here.
What should you ask your surveyor?
- Why is the wet soffit a cold bridge rather than moisture from the ground?
- What did the dry wall below add to that reading?
- Did you test for a leak above the beam, or stop at the condensation you saw?
What are the typical next steps?
- Read the beading as condensation on a cold steel soffit.
- Do not treat the dry wall as rising damp.
- Ask about insulation and ventilation rather than a ground treatment.
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 beam is boxed in later, has the cold bridge gone?
Boxing hides the soffit. It does not, by itself, warm the steel, and the survey has not designed a lining. The note remains condensation on a cold bridge, with a dry wall below, not moisture from the ground. A box can even hide the bead without changing the metal. That would be later work, not a finding that the ground was wet.
Does a tide mark somewhere else in the room rewrite this soffit?
Only if that mark was part of this finding, which it was not. This note is the soffit wet and the wall below dry. Another mark would be its own sentence. Do not import it to turn a cold bridge into ground moisture. The survey has not made that link.