Clay (Terracotta) Roof Tiles are a naturally moist material. Because of that, they attract moss and lichen over a period of time. The tile will retain more moisture over time as more moss and lichen develop, causing the tile to become soft.
Cleaning terracotta tiles annually or bi-annually is excellent maintenance practice.
If possible, hot water should be sprayed onto the tiles which should then be scrubbed gently using hot water and neutral pH soap. S Never use abrasive powders or powdered detergents on terracotta.
But for more serious cleaning jobs and for terracotta roof restoration you need to follow some steps.
1/ First of wall, remove all broken tiles and try to replace them using a similar age and type tile.
2/ It’s always a good idea to have a range of appropriate products on hand at home for cleaning terracotta tiles. Apply an environment friendly product to all moss and lichen soiled areas.
3/ Power wash the tiles with a trisodium phosphate (TSP) cleaning solution, using a garden sprayer. This cleaning solution will remove dirt and debris from the tiles.
4/ Also, clean all surrounding gutters and wash down all external walls and paths affected by roof grime.
5/ Remove all rusted valley irons and replace them with new one.
6/ Repair and air blow clean the entire roof area.
7/ Lay drop cloths on the ground around the roof. Cover anything you don’t want to get paint.
8/ Since terracotta’s porous surface will absorb paint and alter its tone, it is mandatory to lay down primer before coloring clay roof tiles. Prime the roof with masonry primer, using a nylon paintbrush for textured roofs and tight spots and a foam roller for large flat areas. Alternately, use a paint sprayer to distribute an even coat of primer over the tiles. Allow the primer to dry overnight.
9/ Apply a second coat of primer and similar let the primer dry overnight.
10/ Apply two or three layers of latex paint. Let each layer of coat dry prior applying a new one.
11/ Do a final inspection and perform any necessary rectifications.