Roofs and flat roofs
Do Horsham stone slabs, together with the aisle slope, count as evidence on counter battens that may be holding water, or only as a note of what was visible?
Horsham stone slabs on the aisle slope are only a note of what was visible. They do not count as evidence that counter battens are holding water, or that they are clear. The survey saw the slabs as far as it could, and it may have seen battens from the loft. It has not decided how the counter battens are fixed or whether water sits on them. Heavy stone on a low aisle is a covering note. The drainage path behind it was not tested.
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?
Horsham stone is a thick sandstone slab roof. An aisle slope is the lower face over an aisle, often at a shallow pitch where water moves slowly. Counter battens lift the slabs and should leave a path for water to drain. If they are packed or flat, water can sit against the boards. The surveyor cannot see that path from the ground, and a loft view may stop at the ceiling. Naming the slabs records the form of the roof. It does not prove the battens are wet or dry.
Ask the solicitor about leaks over the aisle and about any relaying of the stone. A roofing firm used to stone slabs can look at the counter battens where access exists. The home survey has not lifted a slab and has not said the aisle is holding water. Do not treat the weight or the age of the covering as a test result. The open point is the path behind the slabs, which this visit did not establish.
What should you ask your surveyor?
- How much of the Horsham aisle slope was visible?
- Were any counter battens seen from the loft, or only inferred?
- Does the report stop short of saying those battens are holding water?
What are the typical next steps?
- Read the slabs as a covering note, not a batten test.
- Ask about leaks and any relaying over the aisle.
- Get a stone-roof inspection if the counter battens must be seen.
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 moss on the slabs prove water is trapped on the battens?
Moss shows a damp, shaded surface on the stone that was visible. It does not show the counter battens or prove they are holding water. The visit did not lift a slab. Moss is a prompt to ask about the aisle, not a finding about the timber path underneath.
Is the main slope cleared because only the aisle was mentioned?
No. The question is the aisle slope and the counter battens there. Other slopes were not given a clean result by that note. Ask what was in view elsewhere. A comment on one stone face does not travel across the whole roof.