Damp and moisture meters
Can a slipped stepped flashing where a roof slope meets a wall let rain in, with no valley involved?
Yes. Stepped flashing is the series of steps, often lead, let into the joints where a slope meets a wall, and if those steps have slipped out, rain running down the slope enters the wall head. No valley is required. From the ground you may see a gap, and you may still miss some of the steps.
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?
A valley is the internal gutter where two slopes meet. A stepped flashing is a different detail: the wall alongside one slope, such as a chimney side, a parapet, or the cheek of an abutment. Each step should be wedged into a mortar joint. When the steps slide down, a gap opens above them and water follows the slope into the masonry. Inside, the stain is on that wall, often near the ceiling, which is then misread as rising damp or as a tile failure. The tiles can look even because they are not the piece that slipped.
A ground-level inspection sees some flashings and not others, depending on height and angle. The survey does not lift the steps and does not guarantee the secret gutter behind them. If the report names a slipped stepped flashing, keep the repair on those steps. Do not convert it into a valley replacement, and do not inject the base of the wall for a stain at the top. Ask which length was seen and which was only suspected from the stain indoors.
What should you ask your surveyor?
- Which length of stepped flashing has slipped, and was it seen or only inferred?
- Is there a valley anywhere in this defect, or is this only the slope-to-wall junction?
- Does the internal stain sit high on that wall?
What are the typical next steps?
- Do not commission a valley repair for a slipped stepped flashing.
- Do not treat the high stain as rising damp.
- If the steps were above eye level and not clearly seen, leave that limit in the decision.
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
Is a straight apron flashing the same as a stepped one?
No. An apron is a single sheet, often at the front of a chimney or a window. Stepped flashing climbs the slope in joints. Say which has moved.
Can mortar over the steps hide a slip?
A thick smear of mortar can cover a step that is no longer in the joint. The survey may only see the smear.