A routine home buyers survey of the roof and parapet walls revealed missing coping at the apex of the pitched roof parapet on this London house.
Coping (coping stones or coping units) are typically non porous caps that protect exposed masonry such as garden or parapet walls from the elements. They prevent moisture absorption and help channel water into a desirable run off.
They also tend to overhang the surface of the wall to prevent damp.
On closer inspection exposed horizontal surfaces of vertical mortar joints underneath the coping have deteriorated. Deterioration will occur where the mortar is left exposed to the elements for protracted periods of time – particularly if over particularly cold winters.
The constant freezing and thawing of water trapped in cracks and porous parts of the mortar will accelerate deterioration.
Ultimately this can lead to unstable masonry meaning a hazard beneath as well as potential issues with damp.
This property requires urgent attention.
The problem can be fixed by removing the affected bricks and mortar and rebuilding, a process that is not prohibitively expensive in itself.
However the inaccessibility of the problem will necessitate scaffolding (possibly a tower scaffold) which will add significantly to the cost.