I cleaned this patio. The owner says it’s not travertine, but sandstone, that it’s 2 years old & was sealed right after installation. I surface cleaned after pretreating, standard operating procedure. The problem is there are dark spots, and discoloration along with rust spots in areas where patio furniture was over it. Some of the dark spots where there was a carpet actually look a little green. I doubt it’s algae because my pretreatment is strong 2-3%. I did pressure clean it but they want it sealed and there’s no way I can seal over those areas. The main pic w/the pool has a shot of where the carpet was (lower right)
There are spots all over that thing. I doubt that if it was sealed it was sealed correctly or with the right product. It is either that or the homeowners aren’t aware of how old it is. Sandstone is an extremely porous stone. I have stone at my house that I emptied a gallon of that thompson water seal junk in as an experiment. It leaked out the bottom/sides eventually.
Sandstone comes in pinks, greys, browns, etc, but it always seems that the hardest sandstone is grey, but that grey isn’t all that hard it is actually a pretty soft stone. The reason I mention this is to be careful with the pressure if your working on a tough area.
I actually put wider tips on the SC for this one. But what I am not understanding is the grey areas where the patio furniture was and the darker discoloration where the rug was. I want to seal this patio but I told the customer to let the sun hit some of the darker areas, maybe to lighten it up. I have some oxylic and some rust aid on the way. I have F9 concrete cleaner as well but of course it’s not concrete.
First off, I really don’t think it’s sandstone. Usually with it, you’ll have different sedimentation veins and colors running thru it due to how it’s formed. Go google some pics.
Both are somewhat similar though. You did fine on your surface cleaning, will not hurt if done right like you did. Sandstone is harder but less dense than Travertine or limestone.
It could be a porcelain paver also.
I would call Eaco Chem Tuesday and send them pics and as Brock said post pics on F9 page or message Craig Harrison
The stone up top is is a porous limestone we call shell stone that is white white with little bits of shell in it. Any moisture under it likes to wick up through it and cause coloration issues. Some cleaners are afraid of SH on it for some reason so many use the chlorine free bleach on it… I sell a similar stone and we get complaints all the time about coloration. the top pick looks like that is where the grill was or some seats and sunscreen like was mentioned above, maybe grease shadows. THe other rusty spots are likely cause from moisture pockets underneath. Try ox to spot treat them, low dose. I sell this stuff and i avoid cleaning because of all the complaints. Clients put down a white stone and wonder why it gets dirty.
Maybe the client said shellstone and I heard sandstone. That makes sense. I was thinking to try the Oxalic on those larger areas, to brush it in. And I have some Rust Aid for the rust spots. The one thing that all of the discoloration areas had in common was that they were covered by furniture, or a grill, or a rug etc. etc, and did not get any time in the sun. The client expected them to be perfect after pressure cleaning.
Here’s a couple Afters of those problem areas. I tried some F9 then tried some Oxalic and even some Rust Aid on some areas. In the end I ended up pressure washing it with a nozzle. Most of it started to come off I’d say I got about 80% or more pretty good. I think I would be alright if I had hot water and better use of the F9 products. I think they are made to be used with hot water and pressure. I don’t think you can just brush the stuff on there and think it’s going to work.
