White Residue On Slate Roof

BChester

Hello,
I'm a Paint contractor in Los Angeles and have a question regarding slate/terracota roofs. Many properties along the coast have a white residue buildup on the roof. The roof is very fragile, so I'm asking for advice on how to clean and walk on the roof without damaging it. I figuered pressure washing with some type of solvent, and some burlap bags filled with styrofoam packing for walking. Any suggestions?

Thanks

Grumpy

Slate and terracotta are two different things all together. Slate is a natural stone mined out of the earth while terracotta (AKA Clay) is a manufactured product.

If these houses are located on the coast I can only guess it is a salt build up on the roofs.

To walk on the roofs I do not suggest. If it is necessary, then you should use a chicken ladder so you never actually place a foot onto the roof. Also consider a harness incase you slip off a ladder since a slate roof will be extremely extremly extremly slick if wet. I have to be honest your idea of bags fill with styrofoam made me laugh.