been charged £240 for 12 bags of mapei grey keraflex s1 adhesive from my tiler for 30 metres of tiling + some dips of up to 10mm to level up to....started off with 6 bags then needed another 6 he said..he did show me the 10mm dip..how much coverage does 1 x 20kg bag cover just seems dear for 30 metres of tiling.. he only uses this he says..which if its as good as what he says it is & that hes never had a tile come loose using it maybe its worth paying for top quality addy it just seems really expensive thats all + how much would grey bal grout cost to do the grouting cheers