Problem is that hardwood gains moisture way faster than it can lose it. So if you left it ou there it could take months to accliamate.

Oh I see. Yeah I brought them all in the house now.

They were outside in the garage for 3 days. I hope that wasn't too long.

Also everyone I speak to says I can just install it over my 5/8" OSB flooring with no plywood underneath. My joists are 14" apart.

If you got 14" of clear space that means 16" oc. Guidelines state OSB needs to be 3/4" thick for your situation. What I've done before is install a 3/8 plywood underlayment over the 5/8" OSB.

Your joists are 16" OC. That means, from center line to center line, it is 16". there is approx. 14 " between the joists. But the spacing would be referred to as 16" OC. Your OSB subfloors are most likely 3/4", not 5/8". Look for the stamp on the surface. It may say 23/32. If the subfloors are in good condition and flat, then you can install the wood flooring over those floors without additional plywood, IF your wood flooring is a 3/4" solid nail down floor. You need to lay the new wood flooring perpendicular or at 45 degress ( an angle ) to the floor joists direction. You should not lay the floors parallel to the joists without additional plywood or blocking between the joist bays.

i`ve got 20m2 of junkers oak stored in my garage right now, before install i`ll leave it in the house for a couple of months and then check the moisture readings. i know its going to be bad news.

Hey thanks.

I took a look and the only numbers I could find (or read) were

Grant Wafer Board
Boca No 83-30.

The house is a Brick home about 2500sq ft. It was build in 1984. The whole neighborhood was built by the same home builders. There are two large steal load bearing beams in the basement. It's a pretty solid well built house it seems.

When I measure the thickness of the flooring, it seems to measure exactly 5/8 rather than 3/4. I would really like NOT to have to put another layer of plywood on the floor.

It's funny because every single person I spoke to said it would be fine and not to worry about it. This was also including a 20 year installer who said that he's never had 1 single complaint. He said that the most important thing is making sure the sub floor is screwed flat to the joists before the install. I kept saying that 'people on the internet' said I have to put more plywood on the floor and everyone said no don't worry about it.

That's why I'm confused.. I dont want to have squeaking floors down the road, but I sure would like to do anything possible to avoid adding more wood to the floors as it's a huge bother for me to lay this stuff down. The ceilings feel low enough as they are.

You're house built in 1984 is typical of my area.... many have 5/8" OSB subfloors. We're just giving you the guidelines that NOFMA and the NWFA recommend for laying over 5/8 OSB at 16OC. You're free to do whatever you want to, but I would caution you to re-nail it securely and go perpendicular to the joist and use staples spaced about 5-6" apart.... stay off the ends about 2".

I get paid to install, so no, I could not proceed unless it's dealt with.

I do not think I have ever seen 5/8" OSB. Of course the 7/16" commonly used for roof sheeting and walls. And the full 3/4" T&G used for subflooring, but not 5/8". And not as early as 1984. The earliest OSB was commonly used here on the west coast was the late 80's. Prior to that, it was plywood.

Where i live it was common practice in the 80's. I don't remember if it was early or mid 80's. Back then i was an outside salesman for a lumber yard. The trac build contractors used that frequently (here), then they switched over to 3/4" OSB or plywood, then in the mid 90's they all switched over to using 3/4" AdvanTech. I left in '95

Before we really confuse the OP, lets look at his last post, the sub-floor is "waferboard" not OSB. I personally wouldn't trust this a base for my expensive hardwood.
OP: add plywood to stiffen up the sub-floor and increase nail holding power. This extra work now will go a long way towards future satisfaction.

I get you Dennis, but neither 5/8 waferboard or OSB meets the industry minimums as a single layer subfloor ,16"OC. Only 5/8 plywood meets the minimum.

far be it from to confuse people ...

have a great day

Technically, for 16" o.c. single layer sub, NWFA states either 5/8" ply OR 23/32 OSB are acceptable. But definitely not waferboard.

That is correct. But 23/32" is more like 3/4" OSB than the 5/8" OSB the OP stated he has. Yes, the ONLY 5/8" product accepted by NOFMA/NWFA for a single layer 5/8" wood subfloor is T&G plywood. There is a sticky re: wood subfloor types and the NOFMA approved ones I wrote a few yrs. back. It's in the top of this section.

I've read the specification before and keep bringing it up to the flooring installers that have been a long time in the business. They keep telling me that I don't need any additional wood. These are not migrant workers. These are long time flooring people in the business with their pride and reputation that tell me I don't need it as long as the sub-floor is fastened tightly to the joists.

Here in Canada we have very cold winters. The homes are all built very similar using a lot of the same materials. A lot of neighborhoods are cookie cutter and built by the same home builders so locally the installers know what to expect when I tell them the year of my home and the 'type'. They keep saying it's fine.

I realize that in parts of the US, many installer only install of 3/4 plywood and the homes can come stock with that. I wish that was true up here.

I just don't know what to do.

Also my furnace humidifier can not get the house humidity up to 45%. 25-30% is the maximum it will go so that didn't work out either. At one point last week the house was at 0 so that's better than nothing I guess.

I have all the hardwood in the packaging laying around the house right now and guess I'll have to wait until the indoor humidity goes up naturally this spring/summer.

I sure hope the floors don't creek though after the wood is installed.

Humidifier/s