Hi, I have layed Ardex DPM 1C on a concrete floor. I don't think we mixed it correctly and it won't dry. We have had heaters in the the room and plenty of ventilation but probably 40% of it hasn't dried, probably due to our poor mixing. Im really desperate to get the tiles down for the customer but can't lay them on the tacky DPM surface, or scrape it up as it just smears it around and is impossible to remove. Any advice would be greatly appreciated.