Grout cleaning is one of the more difficult challenges we face.
Article in Cleaning and Maintenance Management this month laid it out step by step with some discussion of the tradeoffs in using different procedures.
Guy who wrote it is describing cleaning the very high volume restrooms at the Orioles’ Camden Yard.
Salient points are:
1) Use a grout specific cleaner – he uses a hydrogen peroxide formulation (as do we) but there are others.
2) Dwell time is important !
3) Pressure washers and or cylindrical brush cleaners are recommended.
4) Use a grout specific floor sealer / impregnator – normal vinyl or concrete seals are not as effective.
5) Two applications of sealer.
6) At least 48 hours “curing time” before wet mopping the floors again.