Damp and moisture meters
Is chipboard that has swollen after a washing-machine leak a form of rising damp?
No. Swollen chipboard after a washing-machine leak is water from the machine, the hose or the waste. It is a local soaking of the floor deck. It is not rising damp, even when the damage is at floor level and a meter reads high on that spot.
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?
Washing-machine hoses, inlet valves and standpipes fail in cupboards and utility rooms. Chipboard and some timber decks swell, lose their surface and stay humped after they dry. The damage maps the flood: in front of the machine, along the kickboard, sometimes into a neighbouring room at the same level. Rising damp is a theory about walls and ground moisture. It does not swell a patch of chipboard under an appliance and leave the rest of the floor flat. A surveyor can see the swelling if it is not hidden by the machine.
The machine may still be in place. The survey does not pull appliances out as standard and does not test the hose. Fitted coverings stay down. If the deck is concealed, the report should say so rather than invent a ground-moisture problem. The Property Care Association's homeowner advice links decay to moisture, so once the leak is stopped you still look at whether the deck has stayed soft. Replacing a damp-proof course does not replace a swollen sheet. Ask a carpenter or a plumber about that cupboard, matching which part actually failed.
What should you ask your surveyor?
- Is the swelling limited to the area around the machine?
- Could you see the hose and the waste, or only the humped floor?
- Are the walls beside it stained, or is this only the deck?
What are the typical next steps?
- Do not call swollen chipboard under a washing machine rising damp.
- Ask when the leak happened and whether the deck was replaced or only dried.
- If the machine hid the worst of it, arrange to see that floor before you rely on it.
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
Does dried-out chipboard regain its strength?
Often it does not. A flat, stained sheet can still be weak. The survey cannot load-test it.
Is a dishwasher the same pattern?
Yes. A leak from a dishwasher is still a plumbing flood of the deck, not rising damp.