This roof is made up of concrete slabs of different levels,"to explain" the house is a council type property the roof I am attempting to seal,were the old outbuildings detached from the house, the last owners attached a roof from the house to the out buildings and is now used as a store but leaking, because of the different levels whats the best solution to stop this leaking

Keith Guy, December 2007

You could try using some self adhesive flashing tape that you stick down over the leaking seams - Flashband and Aquaseal are popular makes,available from B&Q or Wickes.

John, December 2007