I recently had my roof tiled with redland plain tiles, the roof is boarded and has 2 dormer which have warm roofs on them. the roof has breather felt on boards and lathes down rafters then tiled, also has a chimney that has been taken down to below the roof, the boards ar permantly wet and when it rains the water drips off the rafters and the wall where the chimney is soaked. 7 vent tiles have been installed and appear to have helped but still a lot of water. also the ceiling is partly down and still has to be put up and insulated.