We have an arizona buff stone patio. It's 9 years old. It still has that white "leaching" going on. Can we make that stop? Can we power wash it? Should we seal it? if so, what is the best sealant? Thank you! Stacey / Denver CO
The mineral deposits appear because water is leaching up through the surface, carrying minerals with it. A stiff bristle brush takes a lot of it off. Some people put white vinegar in a sprayer and treat the whole patio that way. Vinegar is the tried and tried way of removing minerals. Rinse off with water when done. This is an annual or semi annual chore.
Actually stopping it is another matter. Sealants probably will reduce it quite a bit, since they will stop water leaching up through the stone. I can’t recommend a specific sealant — there are many good brands, just ask at the local home center. Your choice will depend in part on the look you want (high gloss vs. low gloss, for example). Sealants usually need to be reapplied every couple or few years.
Beyond this, make sure rain water drains away from the patio, and do anything else you can think of that will keep the patio as dry as possible.