I know some brands do not have tub or shower surrounds and would assume that the wallcovering is supposedly sufficient. However.....not being one to gamble on having a nasty looking wall, I'd suggest a trip to Lowe's or HD and invest. Can't imagine how that wallcovering is going to hold up using bathroom cleaner to remove soap film or spots. If the tub/shower has a lip that goes up the wall an inch or two, you wouldn't need to caulk that....just the top and side edges. Ours in our ROO and also our TT were left uncaulked to allow for moisture that may creep in to drain out.