Hello to all,
I have a bit of a situation that I need to make a decision and since I'm not an expert in hardwood, I wanted to ask the experts here in this forum to help me with my decision.
Our house construction is going to start very soon (through a builder of course) and I have recently found out that the floor joists based on general plan are laid front to back of the house. Now with hardwood flooring perpendicular to the joists (left to right), we are left with a layout that we do not want as we want our hardwood direction front to back of the house because of important design aspects. After speaking with the builder, we have two options:
1- To accept the hardwood installation's default direction being left to right which we don't want.
2- Sign a waiver and have the hardwood floor run with the joists.

The builder is using a 7/8" OSB subfloor and our selected hardwood is a 5" x 3/4" Engineered hardwood.
Our house has a nice hallway going towards the kitchen and patio door. The house will be hardwood throughout the main floor (including kitchen) and the flow of the hardwood-if installed left to right, will kill the look of the house arcitecturally speaking. But this is what we are getting if we don't sign the waiver.
So now, and before signing the waiver, my question essentially is, with that 7/8" subfloor and the 5" x 3/4" Engineered hardwood, are we safe to run the hardwood with the floor joists instead of going perpendicular (sagging,etc)?
Knowing the kitchen is also hardwood, having bulky and heavy items such as the fridge, etc. would that be an issue?
We did ask the builder to add an additional plywood on top which they refused.
Any comment and suggestion is very much appreciated!
Cheers

Thinking out loud here. I wonder how dated that specification is? Does it refer more to joist systems that are 24 inch on center? Reason is I rarely hear complaints because of separation caused by running parallel to the joists.

Inspectors free to prove me wrong.

Five inch engineered? That means three boards spanning (almost) over two joists (providing Shah has a 16" OC system)

At least 7/8" is more rigid than 3/4" albeit not much but maybe a difference?

Stephen: You're the guy that digs into everything imaginable. What's your take?

The subfloor is OSB (Chipboard). So does it make sense to say that it is less resistant compared to a plywood?
Also- since the kitchen will be all harwood, isn't OSB less resistant to damp and wetness compared to plywood?
wouldn't it make sense to have plywood (7/8") installed instead of OSB?

Well Ken there's guys here that are more familiar with wood substrates than I. Just from what I hear and have experienced is, if OSB gets really wet prior to the walls and ceiling going up it is prone to losing it's fastener holding efficiency.

I've even seen it severely damaged here in the desert southwest. Lots of misinformation out there from the manufacturers. I know experienced hardwood guys won't go directly over it.

And no, it is not less resistant to moisture than plywood. If I were you I would fire my builder if he won't put ply over top of it. Using plywood from the get go is always better than OSB.

If I could post a picture from my pc I have a stunning picture of how OSB swells up when it gets wet and does not return to it's original form. Thus, the loss of holding efficiency.

Thank you Stephen,
Well I had already brought this issue up with the builder...they are not adding a layer of ply on top of the OSB even if I pay the delta. I wonder if it has anything to do with measurements such as the floor height (in relation to the tile floor sections), door heights, etc. due to floor rise?!
I may have a shot at "either-or". Plywood or OSB. So what would be the choice here?
By the way, are we basically concluding that the 7/8" OSB together with the 5" x 3/4" harwood are not good enough to run with the joists?
Thx

If it were me I would go with the 3/4 ply or 23/32 is what it truly is. I'm thinking that 1/8 of an inch difference is not going to make OSB any more structurally better than plywood.
Whats your floor joist spacing again

I'm not sure what the spacing is, but I will ask and get back to you.
I also checked and the builder will not replace the OSB with plywood. So I'm stuck with the 7/8" OSB. Now, the only 2 options I have is either accept the direction they are laying which is wrong or sign a waiver and go with my own direction and run with the joists. what do you think?
On another note, in my current house, I see that our floor joists are approx. 1 ft apart (basement ceiling...as it is unfinished). the OSB is 5/8". Now, the joist directions are not all in the same direction. Some areas are front to back, others left to right. Interestingly enough though, out of the 3 sections in my house that have hardwood flooring, there is one section that runs with the joist, the other 2 are perpendicular. The parallel one, is nice and solid...no sqeaks whatsoever, the other two that are perpendicular to their joists, are all noise and sqeak! Is there an explanation to this paradox?!

Yes, http://www.floorexpert.com/armstrong/fp ... enDocument

http://www.paslode.com/uploadedFiles/El ... 011%2011(2).pdf

So I've been informed that the joist spacing is 24" !!! (The house is 4,010 sq ft- which is by the way total sq footage both floors)
Is this normal???
So what's your take? Can I run with the joists or can't?

Is that normal? Sure it is if your builder is cheap.
CHAPTER 4
WOOD SUBFLOOR GUIDELINES
NOTE: Always follow the wood flooring manufacturer’s recommendation for a proper
subfloor.
3. Truss/joist systems spaced over more than 19.2” (488mm) o/c up to a maximum of 24”
(610mm) require nominal 7/8” T&G CD EXPOSURE 1 Plywood subfloor panels,
(Exposure 1), 4’ X 8' sheets, glued and mechanically fastened, or nominal 1” OSB
Exposure 1 subfloor panels, 4’ x 8’ sheets, glued and mechanically fastened — or two
layers of subflooring. Or brace between truss/joists in accordance with the truss/joist
When possible, check the back
of the subfloor panel for
American Plywood Association
(APA) rating.
Chapter 4 – Wood Subfloor Guidelines
Copyright 2007 National Wood Flooring Association REVISED 3 APRIL 2008
manufacturer’s recommendations and with local building codes. Some truss/joist
systems cannot be cross-braced and still maintain stability.

http://forums.redflagdeals.com/archive/ ... 72341.html


http://www.google.com/url?sa=t&rct=j&q= ... p5J71kgdKQ

This is great advice .OSB is cheaper than plywood so many builders opt for OSB. But like Stephen said, it will not hold as well as plywood. I would definitely opt for 3/4" ply over 7/8" OSB.

Plywood simply has superior holding power and can handle moisture.