wrote in message
ps.com...
I have been installing hardwood for customers for a few months and
things have been going well but seems I met my first challenge. When I
installed 4" wide 3/4" thick mahagony flooring there is excessive
height difference, maybe upto 1/10 of an inch in rare cases, between
adjoining boards.

I investigated and found this is due to the chipboard (3/4" OSB) floor
being very rough. Even though there is 1/5" thick plywood on top of the
OSB the problem persists. To correct the problem do I sand the OSB
floor or smooth it with floor leveling compound?
Or is there another solution?

When I put down a Pergo floor a few years ago there was a requirement for
the floor to be no more than 1/8" (or something like that) out over 6 feet.
I had a place or two where there was a valley and used Jif-Set with vinyl
sealer to level it. I found it to be not quite as self-leveling as
described and used a bull float for additional leveling.

todd