Need help with drywall/construction dust on tile and grout.

[curt johnson]

There is about 1500 square feet of ceramic tile and grout in a home. Grout is supposed to be charcol gray in color. For past 8 months customer has literally been remodelling home. Today I tried to clean with my favorite alkiline cleaner and turbo......some areas came up ok. Most though have tons of white residue still in grout lines. It doesn't seem to help when I scrub with grout brush either. Any ideas on how to get this clean?

 

[Bob Hauser]

acid

 

[curt johnson]

I tried an acid in several test areas. One area it worked ok, The other couple it didn't budge.

 

[Old Coastie]

Viper Renew should do it. Let it dwell, agitate and repeat. The gypsum powder will give way eventually.

Do sections. Use a soft floor brush, like you'd use on a car.​

 

[GeneMiller]

I'm guessing it must have some paint. Drywall mud and dust will just come out with water. I had a huge job that was similar and I didn't notice all the paint drops under all the dust. Turns out the painter sprayed the ceiling without drop cloths. Freaking night mare for me. Took 3 times longer than it should of. I added citrus solve which made my eyes burn from the volume I used.