Roofs and flat roofs
Why might a roof valley be the part a ground-level inspection sees least well?
A valley is the internal gutter where two slopes meet. It often sits out of sight from the pavement, behind a ridge or above a wing. A surveyor who cannot see it should say so. An unseen valley is not a valley that has passed.
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?
Valleys carry more water than the open slope, and a split lead valley or a blocked tiled valley can wet the ceilings below while the slates on either side still look even. From the ground, binoculars help only if the line of sight is clear. From the loft, daylight or staining under the valley is a clue, but stored goods and insulation may hide it. The RICS inspection is visual and stops where access is unsafe.
If the report says the valley was not inspected, that is an NI or a limitation, not a rating 1. Chasing a roofer up to look, or agreeing a drone or a ladder in the terms, is a further step. It is not included just because you paid for a Level 2. Costs vary. Ask what access they need.
What should you ask your surveyor?
- Which valleys did you see, and which did you not?
- Was there staining in the rooms or the loft under the unseen valley?
- What access would a further look need, and is that inside this instruction?
What are the typical next steps?
- Do not read a silent valley as a sound one.
- If the purchase depends on it, agree a further inspection that names the valley before exchange.
- Keep furniture and loft boards in mind: the seller may need to clear a hatch for that second visit.
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 tiled valley better than a lead one?
Neither is automatically better. Both fail in ways you cannot judge from a brochure. The question is whether this one was seen, and what it was doing.
Can moss in a valley be left?
Moss can hold water and block the channel. The survey has not measured that. A roofer who can see the valley should say whether it is holding water or only sitting on the surface.