Roof tiles and mortar joints should be checked every other year at a minimum. Repointing simple mortar cracks can prevent leaking roofs and expensive reroofing jobs. Pay extra attention to ridge tiles since they are exposed to weathering from all sides and may exhibit cracks in the mortar joints before other tiles on the roof. If cracks are discovered in the mortar between ridge tiles, the options are repoint the joints or rebed the ridge tile.
If the cracks are small and the tile seems firmly bedded, repointing the mortar is an acceptable option. If the cracks in the mortar are as wide as the mortar joint and the ridge tile seems to have some movement, it is a better idea to rebed the whole tile instead of repointing. If you repoint a tile that is no longer firmly bedded, the repair will not last very long and the crack will quickly reoccur.
The most important thing to remember when repointing is safety. When working on the roof, be sure to tie off to a sturdy structure. As well as considering your own safety on the roof, it is advisable to set up a roped off area on the ground where falling objects may land. Repointing ridge tiles is the same process as repointing brick or block work. Once you are secured, use a metal spike to rake out mortar in joints you determine need repointing. Dampen the joint, apply mortar, and use a pointing trowel to smooth jointbetween the ridge tiles.
Unfortunately, sometimes the needs to be rebedded instead of repointed which requires a little more work. Again, be sure to use all safety precautions while working on the roof. Use a hammer and chisel to remove the mortar as well as the ridge tile. Use the hammer and chisel to remove the mortar from the bed on the roof and mortar from the bottom of the ridge tile. Once the ridge tile is off, replacing the ridge iron is a good idea especially if there is any evidence of rust. Remove any organic matter such as moss or mold and use a fungicide to ensure the area is clean. Then soak the in water while mixing mortar. Mix a stiff mortar in a ratio of 3:1 (sharp sand: cement). Dampen the roof and tile as you work. Mortar each side of the ridge tile and use a trowel to lay a bed of mortar on the roof. Place on the mortar bed and press down. Remove any mortar that squishes out between joints. Ensure the joint gaps are filled and smooth joints with pointing trowel.
The integrity of the roof protects your biggest investment from damages resulting from weather. Checking and repointing roof before cracks allow water to penetrate into the house are simple ways to save money.