Im going to put down this product to replace carpeting in the house including the kitchen which has a vinyl product over a 1/4" luan type underlay over the original OSB which is in good shape. Mannnington states in its install instructions its OK to go directly over OSB and I have seen it elsewhere in posts. I also have seen some of the flooring experts claim its a mortal sin to not add underlay but if Mannington OK's it why would some flooring people not be OK with it? Its not a huge area and no runs are over the 30' length.

So long as my OSB is in good condition and the joints are flat to within the spec why would I need to add another layer of underlay?

I just want to ask the experts if this is the real world experience or not? My goal is to have the most of the house except the bathrooms and master bedroom, at this point, with this product on the floor with no level changes or need for transitions.

I really do NOT want to have to go thru and put down a layer of underlay in the biggest area of the great room and dinning room where its just carpet over OSB and replace the underlay in the kitchen since the vinyl is glued to the existing underlay.

Im planning on just pulling up the 1/4 inch underlay and vinyl in the kitchen and doing the whole house. Not a big house. The original flooring is under the cabinets but its about the same height as just the AduraMax.

I need to add that there is a second layer of underlay and vinyl over the existing kitchen which isnt a big deal other than when it was put in the door jambs were trimmed and Im sure after putting the AduraMax in on the OSB there will be a gap at the bottom which will require me to replace jambs on at least two door less wall passageways which isnt a big deal. I will gladly deal with that to keep the flooring continuous with no transitions.