Remove Rust Stains from Concrete
LESLIE: Cleaning is on Rita’s mind from Georgia. What’s dirty? How can we help you?
RITA: Hi. I have a retaining wall that has a drainage pipe that comes through it. And unfortunately, the pipe is rusty so every time it rains, our cement platform gets stained with rust. And I’ve cleaned it once already with a power washer but, I mean, I don’t want to constantly do that because I’m going to eat away all the cement. (chuckling) I was wondering if there’s some kind of a sealant that I could put on the cement that would prevent the staining.
TOM: Probably not, because the concrete is so hydroscopic; it absorbs moisture so easily, so readily, that I don’t think you’re going to be able to make it completely impervious to that rust-stained water that’s leaking down there. What you might want to try for regular maintenance is something called TSP – trisodium phosphate. It’s available at home centers. It’s usually in the painting aisle. It’s a powder. It comes in a small box; very concentrated. And if you mix that up …
LESLIE: And you make a paste of it.
TOM: Yeah, a little bit of a paste of it. You can put it on the rust stain; it usually lifts it off. So, Rita, unless you can figure out a way to remove that pipe and eliminate the problem, I’m afraid you’re going to be stuck with it. Because I’m not aware of any type of cement sealant that’s going to be so good that it will stop that rust from showing through the surface. I guess, probably, nothing short of paint; maybe an epoxy paint. But then again, once you paint, you have to repaint.
Rita, thanks so much for calling us at 1-888-MONEY-PIT.