Damp and moisture meters
Render on a coastal house is fretting and salt sits in the pores. Why is that a materials note and not evidence the foundations have heaved?
That is a materials note about the render, not evidence the foundations have heaved. Render on a coastal house is fretting, and salt sits in the pores, which is what salt crystallisation does to a coating in sea air. The survey has described the face of the wall. It has not tested the soil, has not seen the footings, and has not reported heave from salt in the render. The coating is the subject of this note.
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?
Fretting is the surface breaking down, often where salts crystallise as the wall dries. On a coast the salts are a familiar reason for a coating to powder or blister. Heave would be the ground lifting the structure, read from cracks and distortion, and confirmed only by investigation this visit did not do. Salt in pores explains a materials problem in the render. It does not lift a foundation, and the survey has not said the footings have moved.
Ask a renderer or a builder who works on coastal coatings about the fretting, and keep that as a coating repair unless movement is actually described elsewhere. Tell the solicitor this note is salt and render, not heave. Do not open a subsidence or heave claim on the strength of pores in the coating. If the walls are cracked in a movement pattern, that will be a different sentence from this one.
What should you ask your surveyor?
- Is the fretting and salt a note about the render rather than the footings?
- Have you left heave unclaimed from this coastal coating?
- Was the soil left untested?
What are the typical next steps?
- Treat salt fretting as a render materials note.
- Do not rewrite coastal render damage as heave.
- Ask a coating contractor if the fretting is to be repaired.
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 render sounds hollow, have the foundations heaved?
Hollow render is a coating parting from the wall. It is still a materials note. The survey has not reported heave, has not tested the soil, and has not seen the footings move because the face is friable. Friable face is not movement.
Does salt at the base prove rising damp from the footings?
Salt low on a coastal wall often arrives with sea air and rain, not only from the ground. The survey has not used this fretting as evidence of heave. A materials note about pores is not a foundation diagnosis. Pores are not footings.