leveler

In the middle of renovating a very old home and putting down rigid LVP. I have used floor leveler, grinder, sanding to get most of the problems areas level. But this little hallway alcove has me baffled. It has 4 entry ways into different rooms and all are pretty level, but right in the...

From YouTube ive seen, leveler gets applied to the entire room (on concrete slab). In what circumstances can leveler be applied to a fraction of the room? Also, how long should I wait before the moisture content stabilizes before engineered floor can be installed? Thanks!