Hi Guys....newbie here, great forum wish I would have found it a long time ago.

Anyways I am in the middle of prepping my next hardwood flooring project and have a question. The plan is to lay 3/4" Maple in my bedrooms.

I noticed that the subfloor is 5/8" OSB which is not one of the recomended subfloorings as per NORMA (or whatever that group is which I read in one of the articles).

What should I be putting down as as an underlayment before the flooring goes down? Glue and screw 3/8 plywood or something else?

Thanks in advance guys!

Dave

the 3/8 to 1/2" plywood would be just fine.

Forgive me if this is a bit of a stupid question, but the plywood, does it have to be a certain type and should it be T&G?

Best Regards,
DK

Don't have to be Tongue & groove . Actually you should leave a 1/8" gap at the joints for expansion . I like to bring it in the house and stand it up around the walls a few days before i install it . I also staple from the middle of the sheet out to the edges . There are some overly qualified Pros on here , So don't be afraid to ask questions .

Thanks guys

Nick...why do you stand it up around the walls for a few days to install it...I thought laying it flat would be better. Just curious.

Thanks again!
Dave

Lets it acclimate on both sides . faster .
Do you know about floor flatness guidelines . Moisture readings , Nailing pattern for the size of wood you are installing ?
What type of flooring is in the hallway to the bedrooms ?

Hi Nick re your questions

RE Floor Flatness- its fairly flat, there arnt any dips that I could find and any high spots in the original subfloor (OSB) I sanded them down flat

Moisture readings-> I figured it would/should be the same sort of acclimatization instructions as the hardwood as listed on the package before install. (dont have it yet but figured I would follow the same guidelines for the plywood going down).

Nailing/screwing pattern--> I was going to use the guidelines I found online here think it was every 4-6" on the perimeter and 6-8" apart infield...I will 2x check that before I actually get going.

The flooring going in is 3/4" Solid hard maple all upstairs in the hallway and bedrooms (was originally carpet over OSB subfloor).

Thanks,
DK

I use a 6' level i picked up at harbor Freight for $20.00 . Does the same job for flatness as the $100.00 one . Flatness has to be no more the 1/8 " in 6' , or 3/16 " in 10' .
MC of sub floor has to be within 4 % of wood strip flooring less then 3 " wide ,
and 2 % for flooring 3 " or wider .
If you give us the RH and temp of the room we can tell you what the MC of the wood should be at .
You can pick up a electronic hygrometer/thermometer at the rat shack for $20.00 . set it on the floor for 1/2 hr . post the readings .
How wide is the wood flooring ? Nailing patterns vary .

These are all the things I would have never thought of which would probably make a good difference in the long run.

The flooring will be 3 and 1/4" wide.

Thanks,
DK

You can use a 1 1/2 " to 2 " staple . I prefer Two .
1 to 3 " on the ends , and 6 to 8 " down the board .