Hi all, I have a room with old plastic/vinyl tiles on top of concrete floor. I want to put laminate on top of those but there is a 2 foot wide, 10mm deep dip in the floor that goes across the whole room. I used MAPEI 3240 to fill it but within 2 days cracks started appearing and it was lifting from the edges. The vinyl tiles underneath are solid. I didn't use a primer because the tiles are not likely to absorb any moisture. Where did I go wrong? Are there any other products that can stick better to those tiles without cracking? Thanks.