We recently remodeled our bathroom using tile to replace the former vinyl floors. For reasons of timing and indecision, the baseboard was not completed at the time. We have now decided to just use ceramic tile similar to the floor tiles as the baseboard. Since it's been about 5 months since the rest of the bathroom was completed, I no longer have any mortar/mastic left for adhering the tile baseboard to the wall.
My question is, since this is mostly just decoration for the room (not structural or weight bearing), is it really necessary to use proper mortar to attach the tiles? I know I'll need to put grout between them still, but I'm wondering if I could get away with a couple tubes of construction adhesive rather than going through all the effort of mixing and applying mortar again.