Fix/redo grout between ceramic tile and wood laminate before putting down threshold (transition)?

Question

I want to put a floor threshold between a bathroom (ceramic tile) and hallway (wood laminate). I bought, cut, and stained a wood threshold (transition) to fit the door frame, so I would like to use that one if possible.

The grout between the laminate and tile (put in by previous owner probably within the past couple of years) is cracked along part of its length, missing a 1/4" by about 2" chunk in the middle, and separated from the laminate along the rest of its length. I.e., it's not attaching any part of the laminate to the tile.

Do I need to fix the grout before putting the threshold on top of it? If so, does it need to be a good bond, or is it enough to just fill in the gap without doing it over? (I am planning to use Liquid Nails adhesive or the like to bond and hopefully seal the threshold to the floor surface on both sides of the grout bead.)

Answer 1

I don't see any reason to redo the grout unless the gap would be large enough to leave your transition unsupported in the center enough that it could crack if stepped on, which doesn't sound like the case. I would however clean out the old grout. If you don't it will undoubtedly continue to crack and crumble and you'd be surprised at how annoying a sound it can make when someone steps on or near it and the floor flexes. Personally, I'd try cleaning it out thoroughly and caulking the gap. I'd also suggest silicone caulk over Liquid Nails for "gluing" it down as well.