Roof torching

[trog60]

We have a 1930's semi. The torching in the roof needs repairing. Does anybody know if I need special plaster or will ordinary carlite bonding (undercoat) plaster do the job?

[Evorg Enaj]

Carlite will not do the job - it is not waterproof. The most usual way is a mixture of cement and sand 1:3, not too much water, and if you find it a bit stiff to use add a squirt or two of washing up liquid.