3/4 Tongue & Groove plywood or T&G OSB

[Lineman North Florida]

No tongue and groove sub flooring that I'm aware of is going to give you 4x8 once slid together. That measurement is for the outer edge of the sheet including the tongue. Once you slide it together, it will be half an inch short, which adds up with every sheet.

Most floor joists are on 24 inch centers. Going with 19.2 inches will give you a lot more strength with minimal expense. But if it's a small cabin, 16 inches is even better. 19.2 is marked on every steel tape with a red diamond for framing.

As mentioned, Advantech is the best sub flooring out there. It's the same price as the plywood, which makes it a no brainer.

Eddie, I'm getting a little closer to laying the floor and have went with everyone's advice and decided to go with the 25/32 Advantech tongue and groove, my question is if I read you right when I slide these sheets together I will lose about a 1/2" of width coverage on every sheet, and since my building is 20' wide after laying 5 sheets I will lose about 2&1/2" which will put me cutting a narrow strip at one edge which won't matter as it will be under my sole plate of my outside wall. Is this right? Charlie.

 

[RedNeckRacin]

Eddie, I'm getting a little closer to laying the floor and have went with everyone's advice and decided to go with the 25/32 Advantech tongue and groove, my question is if I read you right when I slide these sheets together I will lose about a 1/2" of width coverage on every sheet, and since my building is 20' wide after laying 5 sheets I will lose about 2&1/2" which will put me cutting a narrow strip at one edge which won't matter as it will be under my sole plate of my outside wall. Is this right? Charlie.

That is correct.

 

[Welshman]

Eddie, I'm getting a little closer to laying the floor and have went with everyone's advice and decided to go with the 25/32 Advantech tongue and groove, my question is if I read you right when I slide these sheets together I will lose about a 1/2" of width coverage on every sheet, and since my building is 20' wide after laying 5 sheets I will lose about 2&1/2" which will put me cutting a narrow strip at one edge which won't matter as it will be under my sole plate of my outside wall. Is this right? Charlie.

Just make sure to maintain the specified gap.

 

[/pine]

I am not familiar with the brand named in the above posts...but full net coverage (48") T&G sub flooring is available at many building supplies...other products will net at 47 5/8"

 

[zmountaineer]

Another vote for advantech. When we built our house last year my builder charged an additional $900 for advantech over osb subfloor. I had no clue what it was but he told me that if I was laying hardwood floors by myself then I wanted the advantech bc it would not warp. It was money well spent.

 

[crazyal]

The best way to lay Advantec is start in one corner with a partial sheet and lay it down ending on the floor joist. Do it the 8' way and when you get to the end of your floor joist take the cut off to start the next row. it will stagger out your joints. With a 20 x 40 floor plan you will come up a little short (I'm assuming) on the 20' way but if you want to save a few bucks you can use a table saw to make the groove in the sheet you had to rip down to fill in that last little bit. Also use something like PL400 adhesive to glue it down as well as nailing it.

 

[Lineman North Florida]

The best way to lay Advantec is start in one corner with a partial sheet and lay it down ending on the floor joist. Do it the 8' way and when you get to the end of your floor joist take the cut off to start the next row. it will stagger out your joints. With a 20 x 40 floor plan you will come up a little short (I'm assuming) on the 20' way but if you want to save a few bucks you can use a table saw to make the groove in the sheet you had to rip down to fill in that last little bit. Also use something like PL400 adhesive to glue it down as well as nailing it.

Every 8' I doubled the floor joist so I would be able to land each sheet on a full 1"1/2 joist so I'm probably going to lay full sheets, as far as what I will lose on the 20' width, if I have it figured right I will lose about 2" 1/2 inches , so I thought I would just rip pieces that width and glue and screw it down, I probably won't worry about the groove as this piece will be under my bottom plate which will be 3" 1/2 inches wide, I am going to try to do it this weekend so hopefully it will work out.

 

[buckeyefarmer]

Re: 3/4 Tongue & Groove plywood or T&G OSB

Every 8' I doubled the floor joist so I would be able to land each sheet on a full 1"1/2 joist so I'm probably going to lay full sheets, as far as what I will lose on the 20' width, if I have it figured right I will lose about 2" 1/2 inches , so I thought I would just rip pieces that width and glue and screw it down, I probably won't worry about the groove as this piece will be under my bottom plate which will be 3" 1/2 inches wide, I am going to try to do it this weekend so hopefully it will work out.

Next row Sheets should be staggered, to cover 1/2 each of previous rows. Doubling every 8' throws everything off. If i had a builder do that to me, id fire him immediately. If i saw it in a house i was looking to buy, i wouldnt buy it, I would wonder what else is framed wrong...

 

[buckeyefarmer]

Eddie, I'm getting a little closer to laying the floor and have went with everyone's advice and decided to go with the 25/32 Advantech tongue and groove, my question is if I read you right when I slide these sheets together I will lose about a 1/2" of width coverage on every sheet, and since my building is 20' wide after laying 5 sheets I will lose about 2&1/2" which will put me cutting a narrow strip at one edge which won't matter as it will be under my sole plate of my outside wall. Is this right? Charlie.

That happened on my house using t&g plywood. If i had to do again, id start 1st row with 1/2 sheets, and finish last row with partial shee, to avoid narrow sheet.

 

[4570Man]

3/4 Tongue & Groove plywood or T&G OSB

Next row Sheets should be staggered, to cover 1/2 each of previous rows. Doubling every 8' throws everything off. If i had a builder do that to me, id fire him immediately. If i saw it in a house i was looking to buy, i wouldnt buy it, I would wonder what else is framed wrong...

It would certainly make layout harder than necessary but I don't see any other reason why it shouldn't be done. I do think he's wrong to line the seams up all the way across. He should have used a full sheet beside the 4 foot piece he started with you wouldn't think of laying a block wall with inline joints. Although it's probably less important on a plywood floor.