I have a group of wall tiles coming off the wall. They don't separate from each other, just come off together - when I knock with a finger I hear dull sound meaning there's already a hollow behind the tiles and I also see that the top row clearly comes off the wall.
Normally I would separate the tiles, clean them, reattach them to the wall and seal the seams, but that's more work than I'd like to do right now. I'd rather try to glue them onto the wall without separating. I picked holes in the seams and I plan to inject PVA glue behind the tiles and then press the whole group of tiles onto the wall (I'll put a wide board and insert a bar between the board and the opposite wall).
The question is how do I inject glue behind the tiles? The holes I picked are something like two millimeters in diameter. I thought of using a medical syringe, but I guess its needle has a too small hole and glue is not just flixible enough to be forced through such small holes. Any other ideas?