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  • OSB Subfloor Prep

    Posted by Brian on June 28, 2021 at 1:39 pm


    I’m installing Mannington Adura Max plank (I bought it before finding out that Joe seems to like this product) throughout the main level of our bi-level house (main level is the upstairs for us). The subfloor is OSB. I have a couple of slight dips to deal with and a couple of high spots. I have a bit of a laundry list of questions:

    1) Adura Max installation guidelines indicate it is acceptable to install floating directly over OSB. Is this advisable? Have any of you done it with success? The internet seems to think the movement of the flooring over the OSB will degrade the attached pad and cause premature failure of floor?

    2) Can I sand down the OSB in the high spots? The most would be about 1/8- to 1/4-inch.

    3) Joe uses an Ardex Feather Finish product that he basically screeds over the floor in dips. He suggests Henry’s 549 as a suitable alternative you can buy at Home Depot. Can I use this product directly on OSB to fill dips and other imperfections? Do I need to prime the OSB first to prevent the product from making the OSB swell?

    4) Is a four foot level long enough to gauge floor flatness? Mannington calls for ” flat to within 3/16″ in 10′ and 1/32″ in 12′ “, but that seems pretty excessive and nearly impossible without floor leveler?

    5) This is probably a stupid question. How do I actually find a straight enough 2×4 (or some other product) to use as a screed?

    Additional details if helpful:

    -House was built in 1986

    -Joists are 2×8, 16 on center

    -Central air/Heat

    -Northern Michigan location

    Thank you and sorry for the long post!!


    Brian replied 2 years, 3 months ago 2 Members · 2 Replies
  • 2 Replies