Subsidence, settlement and heave
What should you ask if a floor slopes but the walls are not cracked?
Ask whether the slope is in the floor structure or in the whole room. Joists can sag, a sleeper wall can settle, or packing can have crushed, while the masonry is still where it was. A slope alone is not subsidence. Subsidence needs the ground and the foundations, which a sloping floorboard does not prove.
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?
Old timber floors are rarely level. A surveyor notes a fall and whether doors have been eased. They do not usually take levels on a grid unless the instruction was a Level 3 and they chose to. Without cracks in the walls, the ABI description of subsidence is a poor fit. Deflection of joists and beetle or rot at the ends are timber questions.
The Property Care Association links timber damage to moisture. If the floor is soft as well as sloping, ask about the ends of the joists and the ventilation under them. If it is merely out of level and the boards are firm, do not commission underpinning. A carpenter can say whether the floor needs sistering. There is no national price. Ask them to see the floor.
What should you ask your surveyor?
- Is the fall in one room’s floor, or are the walls and openings out of square too?
- Are the boards firm, or soft at the walls?
- Did you see under the floor at all?
What are the typical next steps?
- Do not pack furniture and call the floor repaired.
- If there are no wall cracks, say so when you ask for quotes, so nobody prices foundations.
- If the boards are soft, look at ventilation and moisture before you buy new carpets.
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
Can a Level 2 measure the slope?
It can say the floor is not level. A full set of levels is not the ordinary Level 2. Ask if you need numbers.
Does a sloping floor fail a mortgage?
Lenders set their own criteria. The survey does not speak for them. Show them the sentence if they ask.