My bathtub has a gap between the tile and the tube on the faucet end, it’s about 1/8 inch. My problem is that when I caulk it, the caulk eventually pushes through the gap because there is nothing but space between the tile and the tub, no backing. What can I do to keep the caulking from pushing through the gap. water comes through the gap and now I have to replace the celing drywall on the first floor. HELP