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.
Once of the major considerations in repointing ridge tiles 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 joint between the ridge tiles
The integrity of the roof protects your biggest investment from damages resulting from weather. Checking and repointing roof ridge tiles before cracks allow water to penetrate into the house are simple ways to save money.