Why parapets fail
A parapet is the short wall that rises above the roof line, at the edge of a flat roof or along a gable or party wall. It is exposed to wind and rain on both faces and from above, and so is more vulnerable than an ordinary wall. Missing or cracked copings, no damp proof course and failed flashings let water in, and freeze-thaw cycles then loosen the masonry.
Warning signs
- Leaning or bowing sections of wall
- Open mortar joints and loose bricks
- Damp staining on ceilings and walls below the parapet
- Cracked, displaced or missing coping stones
- Vegetation growing from the wall top
- Failed lead flashing or roof abutments
A loose parapet is a safety hazard to anyone below, especially next to footpaths. If a parapet appears unstable, keep the area beneath clear until it has been inspected.
Repair or rebuild
Where only the pointing and copings are defective, repair is possible. If the wall is leaning, badly cracked or the masonry is saturated, rebuilding is generally the sounder option. The work usually involves scaffolding, carefully taking down the wall to a sound level, then rebuilding with matching bricks or stone, a damp proof course, and new copings with a drip projecting beyond the face of the wall. Flashings and roof abutments are renewed to tie in with the new wall, see lead flashing replacement.
Local buildings
Terraces in Newcastle, Gosforth and Tynemouth often have parapets along party walls and front elevations, and the coast adds salt and strong wind. Many are in conservation areas, where matching materials and detailing is important. We would normally recommend lime mortar for traditional buildings, see lime mortar repointing. Where the wall carries stone cornices, see cornice repairs.
Shared walls and permissions
Where a parapet sits on a party wall, the Party Wall etc. Act 1996 may apply, see GOV.UK. Rebuilding on a conservation area or listed building may need consent; the Planning Portal explains the process.
Frequently asked questions
Is a leaning parapet dangerous?
It can be, since it may fall in strong winds. Keep people away from below and arrange for it to be inspected and made safe as soon as possible.
Do parapet copings really matter?
Yes. Copings keep water out of the top of the wall. Without them, or with cracked ones, rain soaks in from above and the wall deteriorates quickly.
