Was asked to quote cleaning what I would call a decent amount of concrete (compared to what I’m used to). I was next door doing the neighbor’s house when I was flagged down so I was able to take photos and do a small test spot with about a 4% mix out of a pump up sprayer. I don’t have concerns with the driveway, brick work, or the slab on the back of the house, but along the side of the house the client has this odd stain that is on multiple levels on concrete that lightened when sprayed with my mix but in some areas turned brown. It looks kinda like mildew but it wasn’t sold on it being that so I tested it and I’m glad I did since it didn’t disappear and instead left a brown stain. I also have what looks like a cream layer that is flaking apart. And I’be already spoke to the customer about the discoloration from where a piece of plastic wrap was on the concrete while it was drying. Any suggestions or advice for this awkward stain?
The next to last pic appears to be from the masons using plastic to cover the concrete while it cured and the plastic bunched up. I have seen the inverse of this where the lines indicate where the plastic was off the concrete, normally shows when wet.
Looks like HO got the screws put to them. all that brickwork and concrete. I don’t know what the rest of that mess is. guess is accelerant and tarps and bad timing, things going sideways.
Well, IMO if the grey stain turned brown it’s probably organic and will mostly come off with a couple applications and surface cleaner, especially hot water.
Looks a lot like the mud went off fast on a hot day when it was poured or the customer uses an awful lot of salt.
Down here in South Carolina we use salt on our margarita glasses, not for concrete. 
You try any degreaser on it? Owner not have any idea where it came from? Of course looking at drive, customer could give a crap what it looks like. That’s ridiculous.
Lol your right its putting earings on a pig.
Grease turns brown with bleach sometimes, but definitely when someones tried to clean grease with muratic acid.
That didn’t help much i know.
Rick, I didn’t try any degreaser. To be honest, I haven’t ventured into grease/oil stain removal yet in my small business. The only thing I have in my super small arsenal of chemicals that might**be considered a degreaser would be a small amount of oxalic (F-8). Other than that, I could certainly pick up some Purple Power or ZEP product at a local box store to try out but I haven’t ordered anything specific to target this type of staining.
That’s good to know. The guy was asking me if I did acid washing as he made it seem that after a brick wall is laid it has to be acid washed. His daughter supposedly needs a brick wall acid washed- that’s why that came up. I told him that I like to keep my business as close to a one-trick pony as possible and that I don’t venture into acid washing.
I go here to find information on different things that I am unsure of:
I also talk to some masons I know. I buy them beer and they talk. I am pretty sure, but not 100 percent that those masons used and accelerant on that concrete and your not fixing it. Go see a local mason, make a contact for referring work to or patching mistakes, and get their .02.
My next adventure is putting up some diamond mesh, a scratch coat, and some lick and stick stonework around my foundation. This stuff isn’t rocket science, you don’t have to attend MIT to do it, but pros know tips and tricks.
That’s really just to remove excess mortar dust and small bits of mortar that squeezed out of the joint. It doesn’t have to be acid washed afterwards but it definitely makes a brick wall look nice and tidy.
This. Plus some people acid wash before staining/sealing to clean/break the surface tension of cement or other stuff. It is kind of like wood cleaning: Dampen, apply acid, neutralize (ammonia or arm and hammer), rinse. I’ve done it, but I’m no pro. Lines up nicely with PW to be honest.
If that stain turned brown after applying mix it’s probably just mildew. Hit it with 6%, let dwell, and wash with some pressure. All my mildew covered driveways turn brown when I pre-treat.
Oxalic isn’t a degreaser. Oxalic or, other acids, are used on rust or mineral type stains. Degreasers are for oil, grease, etc.
Yep. My degreaser will turn concrete orange if it’s not saturated beforehand but, yes, if it turns brown after applying SH that means the SH is doing something and that tells me it is likely organic.
Thank you everyone. I submitted a bid and heard back from the customer who would like me to schedule in August. I’ll try to remember to update then.
