Pitched roof maintenance.
General roof maintenance. When this house was built the tiles were given a very short head lap. At the ridge line the gap between the two top course of tiles is too wide. The roof should have had at least two more course of tiles on each side. The mortar was a very weak mix with not much cement in it which has caused it to fail prematurely. We have made our usual mortar which is a mix of 3 parts sand to 1 part cement. Then plenty of bedding mortar has been laid to ensure that the ridge tiles adhere properly.
Previous roofers have tried to repair a large tear in the lead on the valley using a thin coat of hot bitumen tar. Being very brittle in it’s nature this has cracked with the tear as the lead has continued to sag due to excess moisture on the board underneath. Broken slates have made things worse. we have replaced the damaged slates & re-fixed any that were loose or had slipped. Then, after fully drying out the valley, we applied a solvent based glass fibre reinforced acrylic membrane in conjunction with glass fibre chopped strand mat to give the repair lasting strength.
When this extension was built the under felt was left too short from the gutter with no eaves trays to support it. The head lap on the tiles was also far too short at about one inch which has allowed rain to be blown in by the wind & run down the under felt. we have installed felt support trays to prevent the water from pooling at the bottom of the felt & getting into the building behind the fascia. They will also deliver the water into the gutter & not behind it down the wooden fascia.
A combination of multiple problems on this roof has led to a serious damp problem inside the property.