cleaningfireplacegrout
Please see the attached photos. I'm not sure what is even in the grout but it appears stained green-brown with mildew maybe? I used an electric power drill grout brush attachment (see picture) with vinegar to no avail. Do I need to go out and buy a dremel?
Don't re-grout, clean it! Talking with a Home depot guy last year about this and he was amazed I still had to use a brush. He shows me this stuff called oxygen bleach from Ajax. This was literally the easiest method I have ever used. Make a solution with just enough hot water to dissolve it, apply and let it sit for 15-20 min and mop off. That easy. I will never use a tile brush again. Once you get it sparkling white, you can upkeep it my adding a small amount every time you mop and you will have pearly white floors forever.
I used an oscillating multi-tool with a carbide circular blade to grind out the grout. I took it all out, and used a chisel to removed whatever remained. Re-grouting is a grueling task; I could not find anyone to do it.
Sounds like you need to thin that grout. Maybe some latex additive would help. Grout should be pasty but flowing.
When all else fails, I use tongue blades to smooth caulk and grout.
The right consistency grout will not leave bubbles and voids. It will flow and be heavy enough to sink to the bottom.
Best Answer
Have you tried using comet or bleach ?