I removed the grout around a 4'x5' shower stall and now have a worse case 1/2"deep x 1/2" wide void to fill. Should I use sanded or un-sanded grout? (Have been told that sanded is less waterproof.) What about backfilling void half way with sanded, letting set-up then finishing with un-sanded? What about an addative other than water to the grout to make more waterproof?
Any help will be appreciated!