Hi wondering if anyone can help ive tiled the passage, i bought some 12mm ply and screwed it down to the floorboards i then tiled directly onto the ply with ceramic 333/333 using mapei flexible adhesive i checked this morning and some have set and others havent ive had to pull them back up and the adhesive is like moist sand so ive scraped it off mixed up some more and re layed them is this the correct way of going about it the adhesive is taking ages to dry ive had the the front door open all day to help dry it quicker i hope it sets overnight as its becoming a headache now thanks