Hello! Another DIYer who probably got in over their head :)
I'm trying to determine if I'm about to have a problem and if so, how to get ahead of it. My husband and I laid our bathroom floor about 7 months ago (around August/September). The bathroom receives daily use (shower, toilet). I thought we did the necessary research and understood the procedure but these past few weeks I've been hearing "popping" noises from the bathroom during the early morning hours (3-5am). I never really hear it during the day and it will just be one "pop", then a long pause (hard to say how long, I'm usually half-asleep when they happen) followed by another single pop. We've determined it isn't a ghost ;) I'm concerned it might be the tiles slowly popping loose from the cement board, because I feel like some of the tiles are showing more lippage than they used to (my husband disagrees). My husband believes it might be our vanity (??) because it's wood (just a standard builder grade oak vanity I refinished, with the heating vent coming out directly underneath it).
We have a wood subfloor and did the following:
cement board, with thinset (3/4" trowel) and 1 1/4" cement board screws
redgard on the cement board
ceramic plank tiles (6x24)
1/8" space between tiles
We actually left pretty darned large gaps around the perimeter (covered with trim), so I don't think it's the tiles not having enough space to move when the walls breathe. My tiles do not sound hollow, crunchy and do not move when I jump around on them. Pretty much the only reason I'm here is because I feel the lippage seems to be worse and the popping noise (interesting to note: the popping noise actually seems to decrease when the bathroom door is left open at night, exposed to the warm air of the rest of the house).
I am wondering if the winter weather (nights can get very cold here; easily into the 30s) is causing the floor to expand/contract and thus making the tiles come loose from the thinset? My home has a crawlspace underneath it, meaning the subfloor is exposed to the elements to a certain degree. Anyone have any idea what's going on?
And if I do have a problem, is there a fix besides "tear up the floor and start again" (which would be my absolute last resort - but doable if no other choice). Would Fix-A-Floor repair adhesive do the trick?