Shared roof lines, party walls and slipped slates
Terraced roofs run in a continuous line, with brick party walls rising between houses. Where those walls meet the roof, lead or cement flashings seal the joint, and over time they crack, lift or pull away. Slates can also slip when the old nails rust, which often happens quietly across a whole slope.
Because neighbours share the same roof line, a failure on one house can lead to damp on the next. Work to a party wall or a shared gutter can fall under the Party Wall Act, so talking to the next-door owner early is sensible. We check the joins and valleys first, then the main slopes.





