Installed an additional Questech bathroom shelf on a tiled wall. Tried a tube of glue/sealant but it was too slow to set and held the shelf for 30 minutes. Easily removed from wall and order Devcon 5 Minute Epoxy. It has a blue dye that disappears when mixed properly. Nice gesture. This epoxy cures in 5 minutes, so have everything ready in advance [tape, plastic mixing bowl - I use old, clean deli bowls, mixing and applicator sticks, spirit level, etc.]. Don't land on surfaces you don't want to. Apply the mixed epoxy to the edge of the shelf and smooth it out. Pushed him 5 inches hard against the wall. I felt he was tight. I pressed for another 5 minutes. Stick it on the wall and leave it for 24 hours before placing items on it. Devcon was perfect for attaching an item to a vertical surface. Comes with caps to seal vials for reuse.