We've remodeled our bathroom and re-tiled the shower(below grade, concrete block shower stall).Concrete blocks laid 30 yrs ago weren't straight, so we did our best to remedy that with tile mortar. Last step is installing the pivot shower door, and due to the tiled wall area where the door frame will fit not being level, we're not sure how to proceed. Portions of the tiled wall are off level (ranging from 1/16" to 1/4" variance from being flush). So, the left side of shower door frame will fit flush against tiled wall at the top, but that leaves a 1/4" gap at the bottom portion of the shower door frame (from bottom sill to about 18" up).That gap is going to cause huge water seepage problems into the outer bathroom area. We very briefly considered filling with caulk, but it's just too large an area: the caulk would seep into the recessed area of the door frame which is about 1/4" deep, 1" wide x 18" high. A wood shim would retain moisture and rot. We're wondering if Great Stuff foam insulation (in aerosol can) might sufficiently fill in this large gap. We could then use caulk to fill in the 1/4" gap between the door frame and tiled wall, and the caulk would also cover the foam insulation so it's not visible. We have to watch what we use to fill this gap, high moisture content in this below grade bath creates mildew conditions pretty quickly. Any thoughts/suggestions greatly appreciated!