Terra cotta barrel tile - can be very fragile to walk on so make sure the crew is experienced in walking on these tiles and (silly as it may sound) it's better if they are light-weight. Also, because the top (crest) of the tile is much higher than the valley (trough), rotary surface cleaners aren't used, which means the technician will have to manually use the spray wand (pressure gun) to thoroughly clean all surfaces of the tile thus making this tile type more labor intensive.

Concrete flat tile - usually concrete is a very strong material. It can be cleaned with the rotary surface cleaner but the leading edge (the thickness or height) of the tile needs to be cleaned row by row manually with the spray wand to get the roof appearing completely clean. It is not as labor intensive as the terra cotta barrel tile, but does involve an extra step to do the job right. One added word; white flat tile from the factory can be color through or painted. This means that pressure cleaning an older and moldy roof on the painted variety of tile may expose the light gray concrete of the tile material. The tile is still clean but may have light gray showing through in spots. (Remedy? Often people have these tiles repainted with special roof paint.)

S-type tile - or modified S-type tile is usually concrete, strong and easier to clean than the previous two types. The cleaning technician will complete a well-done job by making sure ridge tiles and tiles along the edge of the roof are cleaned thoroughly