Hi, I'm looking for advice on whether a waterproof upstand tape/strip is essential? I've had to remove a cracked resin curbless shower tray. I managed to do so without damaging the wall tiling. I've reinforced the subfloor and have a replacement tray (Merlyn Truestone). Can I get away with placing the new tray down, leaving the tiles as they are, and sealing the edges with silicone or do the edges that meet the tiled walls require an upstand and I therefore am best to remove the lower row of tiles, fit an upstand strip around the tray and then tile over? I was hoping to get away without adding tiling to the job but will do it if necessary! Guidance appreciated 
