can i lay 3/4 inch naildown wood on a press wood subfloor

By "press board" do you mean Oriented Strand Board (OSB) (pressed wood chips), or do you mean flakeboard (sawdust pressed into sheets) ???

If Flakeboard, then no, that is not an approved subfloor for hardwood flooring (except for floating wood floors), and in fact, I believe the only approved floor covering is stretched carpet or other floating floor systems, over that subfloor.

If OSB, then it really depends on the type of OSB Structure Panel Subfloor that it is.

OSB - Oriented Strand Board, has different grades.

Bruce/Armstrong, a well known 3/4" natural hardwood strip/plank manufactuer, states the following:

"... Structural panels/underlayment must be installed sealed side down. When used as a subfloor allow 1/8½ (3.2 mm)

expansion space between each panel. If spacing is inadequate cut in with circular saw. Do not cut in expansion

space on tongue and groove panels."

and, they go on further ...

"• Oriented Strand Board (OSB): Conforming to US Voluntary Product Standard PS2 or Canadian performance

standard CAN/CSA 0325-0-92 construction sheathing. Check underside of panel for codes. When used as a

subfloor the panels must be tongue and groove and installed sealed side down. Minimum thickness to be 23/32½

(18.3 mm) thick when used as a subfloor or 3/8½ (9.5 mm) as underlayment. Some board manufacturers recommendations vary."

Please be aware that if it not of sufficient quality, the manufacturer warrenty may be voided.

Have your local instalaltion professional check this out before the isntalaltion and make sure to mention it specifically to him, then check with the manufacturer of the product you choose to make sure.

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