Out here cleaning the windows on this 30,000 sq ft monster. I go to the back, and there are some “stone” guys spraying outdoor bleach from a spray bottle onto the staining areas of the stone, and using a small hand held brush. It isn’t cleaning anything at all. Says there isn’t much you can do to remove and prevent the patina of the limestone. Says they installed it all, but since it’s a high profile account, they want to take care of the “cleaning” part, too.
Does limestone patina? Isn’t there a better and more efficient way to clean this and keep it clean?
What you show is not patina. Patina is the change that occurs to the surface of the stone as time and exposure tighten the surface that was created during fabrication.
What you show is staining. Typically caused by airborne pollutants that react with the stone itself. It shows itself in this unattractive manner because it is being fed and aggravated by water that is allowed to run over the face by improper architectural detail specifications and/or construction details.
You are correct to question the crews methods, knowledge and efforts. There is typically nothing good about salt water on the soft limestone that you picture.
Sure, give me their number and the best time to call.
Is this the big job with tight deadlines? Perhaps another time would be better to discuss this with the client with just a mention at this time. From what I can tell from the one pic that you posted, this staining is addressable but will only get worse with continued wet/heat cycles. It may not always get worse appearing so much as deeper set and increasingly difficult to remove.
This is what I like to call “restoration grade cleaning”.
Probably not. I assume that this stone surface is not polished but more of a sandpaper type feel? Wand marks are really just accelerated wear. You can’t undo that. The only thing that you could do would be to abuse the surrounding surface so it was all abused somewhat evenly. Not a good plan.
I know that you are on site with a focus on other things, but if it took a while for these to come to your attention, it is possible that the owner is not aware of them or perhaps not bothered by them. I would document the abused areas well but would not make an issue of them unless necessary.
Talking to the guy who is scrubbing the limestone with a brush and spray bottle of bleach. Apparently those wand marks are fresh. The guy who hired the guy I’ve been chatting with, tore it up last week, and now hasn’t been seen since. Unfortunate.