Damp and moisture meters
What should you ask if mould is only behind a wardrobe on an outside wall?
Ask whether the surveyor could see the wall, or only the furniture, and do not treat that mould as proof the damp-proof course has failed. Cold outside walls grow mould where air cannot move, which is a condensation pattern. A leak or penetrating damp can sit in the same place. The home survey should say which clues it actually saw.
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?
Government damp and mould guidance is about cause and health risk, written for rented housing. It does not tell a buyer that mould behind a cupboard is rising damp, and it does not set a repair price. A pin meter on a cold, salty or recently washed wall can read high without naming the source. The Property Care Association still wants the building looked at, not only the furniture.
Move nothing on a viewing that is not yours. If the seller will pull the wardrobe out, look for a tide, a crack, or a stain that continues beyond the furniture. Mould that stops at the cupboard outline is a ventilation clue. Mould with a leak from above is not. There is no RICS price for a new wardrobe or a new damp course.
What should you ask your surveyor?
- Could you see the wall, or was the furniture hard against it?
- Is the mould only in that outline, or across the wall?
- Are you describing condensation, penetrating damp, or something you could not separate?
What are the typical next steps?
- Ask the seller to pull the furniture out before you price a repair.
- Do not buy a chemical damp course because a cupboard was mouldy.
- If someone in the house is affected by mould, treat that as a health reason to find the cause, not as a rating by itself.
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 an outside wall always grow mould behind furniture?
No. It is a common place for condensation. It is not a rule, and it is not a diagnosis.
Is black mould the same as wet rot?
No. Mould is a surface growth. Wet rot is decay in timber. The survey should not use one name for both.