Roofs and flat roofs
Lead on a bay roof has split at a drip and the timber roll looks intact. What movement of the deck was not measured under that split?
The movement of the deck under that split was not measured at all. The lead on the bay roof has split at a drip, and the timber roll beside it still looks intact, so the survey can describe a crack at the joint and a roll that has not obviously failed. It cannot say how far the boards moved, whether they are still moving, or whether the split is only the lead tiring in its bay. No dimension of that movement was taken on the day.
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?
Lead splits when temperature change fatigues it, or when the deck under it shrinks, springs or opens. A drip is a joint between bays. An intact timber roll means that wood edge still looks continuous. It does not measure the boarding between the rolls, and it does not show whether the deck dipped where the lead let go. The survey did not lift the lead or record a movement.
A leadworker can say whether the bay wants a new piece dressed at the drip, and whether the boards under the split need fastening or repair before new lead goes down. Tell the solicitor the survey names an unmeasured deck movement, not a cause already proved. Do not read the intact roll as a sound deck. The home survey did not open the lead and did not test the boards.
What should you ask your surveyor?
- Where is the split in relation to the drip, and how long did it appear?
- What of the timber roll still looked intact beside that split?
- Did you measure any movement of the deck, or was that left unmeasured?
What are the typical next steps?
- Treat deck movement under the split as unmeasured.
- Ask a leadworker to see the drip and the boards beneath it.
- Do not read an intact timber roll as a still deck.
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
If the roll looks weathered but whole, is the deck steady?
No. The roll is the timber edge the lead dresses over. The survey saw that roll looking intact and the lead split at the drip. It did not measure the boards between the rolls. A whole roll can sit beside a deck that has moved at the joint. Steady boards were not shown.
Does a split at a drip always mean the lead bay was too long?
Not always, and this visit did not decide that. A long bay can fatigue, and so can a deck that moves. The survey saw the split and did not measure the deck under it. It did not gauge the bay against a design rule and it did not choose a single cause. Both remain possible until the lead is opened.