T&G flooring issues....

[NM_Shooter]

So I am looking at the Advantech T&G, which looks nice, but the smaller overall surface sizing has me a little concerned.  It appears that the deck area (non tongue size)is 47.5".  But what about the length

Is there a T&G connection for the length, or do you just line that up on the floor joist and be done with it?

I guess I could deal with the narrower width in two ways:

1)  Make cabin narrower by 2.5"

2)  leave cabin at 24 wide, center the advantech, and put in filler strips of similar material under the base plates.

Don... the guy at Hunter said that it was 3/4", but I didn't see that as a mill offering.  Maybe it was actually 7/8" ?  I'll check.

What do you folks think about option #2 above?

-f-

[MountainDon]

I believe there is no T&G jointing on the 4 ft ends, only along the 8 ft sides. With the panels placed with the long dimension perpendicular to the joists those 4 ft ends would fall across joists, whereas the long ides bridge from joist to joist.

With my 15 ft width I'll simply trim the last sheet off to fit exact. It just means my scraps will be a little narrower. I didn't have a use for them for sure anyhow.

[ScottA]

The product measures 47 1/2" x 95 7/8" net not counting the tongue. You are suposed to leave a 1/8" gap on all sides so you lose nothing on the long dimension and 3/8" on the short side. Tongue and groove are along the long side. Short side is a square edge. I'd just narrow the cabin to allow for the difference. I don't think it's worth the trouble to add a strip on the sides. This product will stand up to alot of rain as I have it in my cabin and it's been rained on atleast a dozen times. Some slight swelling has occured at the edges but it's very minor and should be easily taken care of with a belt sander.

[John_C]

Years ago when I built my place which is 24' wide, this is what I did.

The AdvanTech runs perpendicular to the floor joists. The 8' lengths end on the mid point of the joists, no problem.

I ripped about a 2" piece off the groove side of the first sheet and cut that strip into 1' lengths.

I laid the now 45-1/2" sheet flush with one side of the floor glued and nailed it down,  Do not nail the last 1' of the tongue side until the next sheet is down and the tongue-groove brought up snug.  That is where the cut off piece comes in handy. The tongue - groove fit was VERY tight.  Put a 1' piece of the cut off groove end over the tongue of sheet 2 to protect the tongue and use an appropriate heavy hammer to tap smash it together with sheet 1.  Again do not nail the last 1' of sheet 2 until you get sheet 3 down. If you nail to the edge it makes it a bit harder to get the sheets together.

After sheet 6 you will need a ~ 5" piece to cover the 14' width.  1/2" for each of the six sheets + the 2" you cut off sheet 1.  Just cut a 5" strip off the groove end of sheet 7  to fill that space.

The now 42-1/2" wide sheet 7 is used to start the next row of sub floor.  Basically you will need just 1 extra sheet unless the floor is quite large.  If the sheets go together easily you can forget about the 2" piece for "tapping blocks" but I remember "tapping" mine with a 12 lb. sledge.

As always YMMV.  Since I'm planning on doing this again soon I'm open to suggestion for a better method.

Added:  As Scott said the joints are not brought up tight.  Mine, however required considerable persuasion to get close.  That was 20 years ago, tolerances may be different today.

[Redoverfarm]

The odd finished size for me was not really a problem as my total length was 40'. I just added what was required at the end. My major concern was the time it took to build the log walls and flue construction to get the rafters in place. My floor set for several months with rain and snow.  Even after the roof was on the windows and doors were not set and rain poured in on the floor as well.  The advantex worked as it was designed to in that the water just pooled on the top and evaporated.  The only thing I did notice was that the top did get a little grainy but this will be taken care of with the finished floor. On the other demension of width of 16' the little that I did add was under the sill log (8") and it was attached to the rim joist and was not really a problem.

[Willy]

Personaly I would spend a little extra & buy a few more sheets and rip some off to split them allmost in haft. This way you woulld have no breakes in the floor under the plates for a stronger floor and wall system. The point of putting the plywood under the walls is to tie it all together. Having a strip of plywood does not tie the sole plate to the floor in a real strong way like a 2-4 ft wide sheet would. Start off with a 30 inch wide 8 ft long peice and use the full sheets after that. When you get to the other side cut off the extra plywood and depending on how you lay it out it should be around 2 ft or so left over to do something with. Mark

[Redoverfarm]

Mark I usually nailed my plate to the rim joist and floor joist so the subfloor did very little in the way of structural anchoring.  That is with stick framing. With the log plates it didn't make any difference.

[Willy]

Mark I usually nailed my plate to the rim joist and floor joist so the subfloor did very little in the way of structural anchoring.  That is with stick framing. With the log plates it didn't make any difference.

Dosen't the plywood floor help hold the rim joist from being pulled away/off also?I know in balloon framing they put the plywood down after the wall is built. Mark

[MountainDon]

I've thought about this a bit more and Mark may have a valid point about the rim joist. I don't know for sure. 

Perhaps the best solution, while maintaining the best possible strength, would be to narrow the cabin the 2.5 inches. The worst thing you'd then run into would be having to trim a couple of exterior sheathing panels.

[John_C]

If it's an issue just cut 16" or so off the first sheet of sub flooring.  You will get lots of overlap all around and still only need one additional sheet in a modest size cabin.  Changing the width to avoid a few plywood cuts might come back to bite you.  If you have comprehensive scaled plans virtually every width based dimension would have to be reevaluated.  Foundation, ceiling joists, rafter lengths all would change.  There might be places where a code stairway, code hallway and min U shaped kitchen fill the width. 

The bottom plates are nailed to the rim joists and floor joists. Unlike higher up there isn't a lot of outward force to resolve there. 

[Willy]

If it's an issue just cut 16" or so off the first sheet of sub flooring.  You will get lots of overlap all around and still only need one additional sheet in a modest size cabin.  Changing the width to avoid a few plywood cuts might come back to bite you.  If you have comprehensive scaled plans virtually every width based dimension would have to be reevaluated.  Foundation, ceiling joists, rafter lengths all would change.  There might be places where a code stairway, code hallway and min U shaped kitchen fill the width. 

The bottom plates are nailed to the rim joists and floor joists. Unlike higher up there isn't a lot of outward force to resolve there. 

That what I was tring to say in my post above to take care of this problem if needed. On my cabin even if I wasted the extra plywood it is only $33.00 worth of plywood to deal with 24 ft of length. I am sure the extra could be used some where on a cabin later. Mark

[MountainDon]

Frank's plans are in flux, self drawn. He has no code concerns. Like me he hates material waste.