High quality roofing tiles are durable, and most will last over a century. It is rare to have problems with anything on a large scale unless the roof tiles were installed incorrectly or the tiles are of low quality. And, while you will spend more initially on a tile roof, over time they can be very cost-effective.
Moss and algae won’t eat through a tile roof very quickly, certainly not as easily as with a wood shake roof. And most of the time, tile roof repair is not as urgent in nature as it is for other materials. Because tile roofs are expensive to install, it is much better to repair the tiles than replace the roof.
The most common two problems with tile roofs are cracked or broken tiles and debris buildup.
As with all roof maintenance, keep overhanging trees cut back to reduce shade and debris. This will slow the development of moss and algae and reduce buildup of debris. To inhibit moss growth you can fit a copper wire net to the ridgeline. Water running over the copper will reduce the amount of moss that grows below it. (If you collect rainwater for drinking, do not use this method.)
Build up of moss and debris in the slots between the tiles can cause water to back up under the tiles. When this happens, it can be difficult to determine the source of a leak. Tiles hang on long strips of wood that run horizontally, so water that gets behind the tiles can follow the boards and cause a leak in another area. Valley sections of the roof are particularly prone to this problem, and should be cleaned every year.
Pressure washing is the most safe and effective way to clean moss and algae.
Fixing and Replacing Broken Tiles
Tiles can break or become damaged by extreme weather conditions such as high winds or large hail, improper installation or from being walked on. When working on the roof, work on planks or a roof ladder. If you walk directly on the tiles, they will break.
If your roof starts shedding undamaged tiles for no apparent reason, it could be that the installer used cheap galvanized nails instead of copper or stainless steel. In this case, relaying all the tiles with the proper nails is the only solution.
Some tiles can be repaired with silicon sealant or adhesive.
To replace a tile, pry up the tile just above the broken one. Break the damaged tile into smaller pieces and carefully remove them. Pry out nails. Spread a small amount of roofing cement along the underside of the replacement and slide it into place. For a single tile replacement, just the adhesive will be sufficient. Press all tiles down snugly.
Matching tile on an older roof can be challenging. Roof tile suppliers that carry a large inventory of salvaged roof tile can be your best option. If you can’t find a match, you can take tiles from a less visible part of the roof and fill that spot with the closest match you find. Use the matching tile on the more visible areas. You can also have custom tiles made, but this is expensive and getting an exact match is not guaranteed.
Fixing Metal Flashings
If you have metal flashings that need repair, often you can lift the tiles just around the flashings, replace them and return the tiles. You may also find and replace broken tiles at this time. Whether you do the work yourself or hire a roofer, care is needed when working on a tile roof or you will cause more damage than you repair.