An underlayment is a thin layer of material sandwiched between two other materials.
Floor with low spot wood.
Mix the compound as directed on the package then pour it onto the low spots in the floor.
Fill cracks or major voids with wood putty or a self leveling compound.
It s used to help insulate absorb sound and reduce wear on your floor.
Use a trowel to spread the material then allow it to dry before proceeding.
Use builder s felt or shingles stapled to the floor to fill small low spots if you.
3 set a long straightedge tool or a straight piece of 2 by 4 inch lumber.
Use a mixture designed for wood subfloors.
Use deck screws or ring shank nails set into the floor joists to secure loose or squeaking pieces of wood subfloor material.