Roofs and flat roofs
A flat-roof upstand finishes below the coping of the parapet. What path does wind-driven rain then have, if the felt field itself is intact?
Wind-driven rain can pass over the top of that low upstand and down the back of the parapet, even while the felt field itself stays intact. The upstand stops below the coping, so it does not finish under the coping or high enough to close the junction. Water driven at the parapet can get behind the membrane at the wall head. The survey has seen the relative heights. It has not sprayed the detail, opened the coping, or shown that the wall head is dry.
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 flat-roof upstand is the turned-up edge of the covering at a parapet. The usual intention is that the felt is taken up and protected by the coping, so rain on the face is shed outside. If the felt stops below the coping, wind can push water over the top of it and into the masonry. An intact field, away from the wall, says nothing about that edge. The survey recorded the levels and did not test the path with water.
Ask a roofer whether the upstand can be carried up and tucked under the coping, or otherwise weathered, and keep that quote separate from the condition of the main field. Tell the solicitor the report names a path at the parapet, not a failed sheet across the whole roof. The home survey has not opened the coping and has not certified the wall head as dry.
What should you ask your surveyor?
- How far does the upstand finish below the coping, as you saw it?
- Did the felt field look intact while this parapet junction did not?
- Did you see staining on the wall head or the ceiling beside that edge?
What are the typical next steps?
- Treat the low upstand as a rain path at the parapet.
- Ask a roofer about carrying the covering up under the coping.
- Do not read an intact felt field as a sound parapet junction.
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 ceiling under the flat roof is unmarked, is the path closed?
No. A clean ceiling does not show what wind-driven rain does at the parapet. The survey saw the upstand finish below the coping and did not water-test that junction. Staining can take time to appear inside. The field of felt being intact does not cover the gap at the wall head.
Does the coping stone itself make the upstand tall enough?
Only if the covering is taken up into or under it. Here the upstand finishes below the coping, so the stone is not completing the felt. The survey recorded that gap in the detail. It did not measure a drip or certify the coping as a cover to the membrane. The path over the top of the felt remains the point.