I'm trying to plan a tiled hearth. It will be in 146x146mm square tiles on chipboard using flexible wood floor adhesive. These come out to 150x150 when there's a 4 mm gap.
I want them to overhang the top by one tile thickness and lay a layer of tiles round the sides. The question is how much thickness should I allow for the adhesive once it's dried to calculate how big the chipboard panel should ? Is this significant?