Can hardwoods be installed over a subfloor covered in black mastic?
I recently purchased a house built in 1964. Most rooms have 9x9s under the carpet which I will assume contain asbestos. The previous owner removed the 9x9s from one of the rooms, exposing the black mastic covered plywood subfloor. For the purposes of my question, I'm assuming the black mastic has asbestos as well.
If I cannot install directly over the black mastic, does the subfloor need to be replaced?
Maybe I shouldn't say this...but I've done this after laying down wax paper over the mastic. It's not the ideal way and I'm sure others will chime in and say I'm a hack but this job was done 2 years ago in a rental unit with no problems to date.
Assume this is asbestos impregnated. Remove any of the loose tiles and fill the voids with either a self leveler compound or spread a comparable floor filler in its place. Rent a hammer nailer, buy plenty of nails and set the nails through the tongue about every 8" - 10". You ought to snap chalk lines along the joists(below the subfloor) to insure that you catch something solid every 16". Be sure to leave a 1/2" space between all sides of the walls and floor boards for expansion/contraction. Pound the boards together before each nail that you set with the BFH/big fabulous(rubber) hammer, which is usually supplied by the rental place. The last row of boards will need to have nails predrilled and set through the top of each board. The base board and shoe molding then get installed over these after you sand the floor. Unless the flooring you have choosen is a prefinished type.