www.ultimatehandyman.co.uk

Hi, First post on these forums so apologies for any lapses in etiquette.

Bathroom window above bath/shower has developed a thin crack along the top of the tiles on grout line. Top three tiles have slight movement at the top of tiles. I'm guessing some water has made its way back there causing the issue. My question is how serious 'could' this be? I appreciate without being there taking a look advice is difficult. I am just wondering if it could be an option to inject/force into the gap some new adhesive/grout, push back on the tiles and wait for it to re-stick.

Tiling was done prior to us moving in so I cannot comment on how bathroom renovation was done/what is behind.

Additionally I believe we do have some spare tiles under the bath if it helps solutions.
Many thanks.

I can only take an educated guess at the cause, but regardless the tiles are moving, which probably means there is an issue with the adhesive.

Get a grout rake and remove grout around the problem areas. a stripping knife or similar can then be used to "peel" away the loose tiles, with care you shouldn't break any.

Once off take some pics of the wall , soak the tiles in a bucket of water. (edit.. does the adhesive wipe off after a few hours ?)

My best guess is that a pre-mixed adhesive has been used. no good for wet areas.

that job looks like a diy effort.the thin ripping of tile in the inside corner and bringing the wall tile up with the flat sill tiles.
the sill tiles or a length of edging trim should come over the wall tiles.
you might be best to take off any suspect tile on the wall or the sill. in fact, it will probly work out best removing all the sill tiles and the five wall tiles below and then posting photos of what you find.
i've seen this kind of stuff lots of times and its best practice to go for the root of it. your proposal wont work.
thing is if you have kiddies then its obviously dangerous to risk any large tile falling off when theyr in the bath.