Chimneys and parapets
White salts on a chimney breast stop at the bedroom ceiling and do not reach the floor. Why is that not the same pattern as rising damp?
Because the salts stop at the ceiling and never reach the floor, which is the wrong direction for rising damp. White salts on a chimney breast, ending at the bedroom ceiling, fit the flue and the stack above, not groundwater climbing from the skirting. The survey has recorded the height the salts reach. It has not diagnosed rising damp, and it has not sampled the deposit. Rising damp marks the bottom of a wall and works upward. A pattern that stops overhead and spares the floor is a chimney pattern. The two should not be given the same name.
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?
Flues carry moisture and combustion deposits. Salts from that path, or from rain entering the stack, come out on the breast and often fade as you come down the house. They are hygroscopic, so they can look damp in humid weather without a leak that day. The bedroom ceiling is a natural stop if the problem is the stack in the roof, not the ground. A rising-damp storey would still be visible at the floor.
Ask the surveyor whether the salts were only on the breast and only above that ceiling line. The next look, if you need one, is at the stack, the flashing and the flue, not at a chemical damp-proof course in the ground floor. Tell the solicitor this is a chimney-breast pattern. Do not let an injector's report reuse the word rising damp for salts that do not reach the floor.
What should you ask your surveyor?
- Do the salts stop at the bedroom ceiling and spare the floor?
- Are they limited to the chimney breast rather than the whole wall?
- Have you kept this separate from rising damp?
What are the typical next steps?
- Read the salts as a chimney-breast pattern from above.
- Do not call salts that miss the floor rising damp.
- Look at the stack and the flue before any damp treatment.
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Also asked about this
If the salts feel damp in summer, has rain got into the flue?
Not proved. Hygroscopic salts draw moisture from the air and feel damp without a leak that day. The survey has not sampled them and has not shown rain entry. The pattern is still not rising damp, because it does not reach the floor.
Does a capped pot clear the breast?
No. A cap changes the flue opening. It does not remove salts already in the plaster, and the survey did not treat a cap as a test. The finding remains salts that stop at the ceiling. No extra conclusion about the chimney-breast salts should be read into the wording.