I have got ponding on my existing roof. Do I need to replace the roof?
Not unless it is leaking, or showing other signs of deterioration. If and when you do have it replaced, you should tell the contractor so that he can check the cause of the ponding, and itemise the cost of dealing with it in his estimate. I have just had my roof replaced, and it is still ponding (where it did before). Unless the contractor was told about the ponding he is unlikely to have quoted for changing the falls, which would have meant removing the decking, placing firring pieces (wedge-shaped timber strips) upon the joists, and re-fixing the old deck or a brand new one, prior to installing the new waterproofing system. This could have doubled the cost of the works. It may be that the decking had deteriorated and sagged between the joists, in which case it should ideally have been replaced. See Householders Guide to Flat Roofing pages 5, 6 & 7. I have just had my roof replaced, and it is now ponding (when it did not before). If the contractor has simply followed your instructions
