T&G which way up?

[JohnD]

I am putting down some flooring ply.

the groove is not quite in the middle, one surface has a thicker lip than the other.

Is it best layed with the thick lip up or down?

Also, the last board will be about 20mm from the wall, with pipe obstructions. Will it be easier to put it in with the tongue going into the penultimate board's groove, or a groove if I lay each preceding board with the tongue facing out?

 

[masona]

John can you take a photo as some plywood T&G have difference tongue

Normally it's the thickness bottom of the groove or the longest which support the tongue more

 

[noseall]

writing side down.

 

[JohnD]

no writing

but on further examination it looks like the ply is symmetrical

sorry

It would not fit into the existing chipboard flooring, which is not symmetrical, but I intend to pull it up across the whole width of the room so it doesn't matter.

i will have a square-edged joint part way along the length of the room, I will place this over a sistered pair of joists so old chipboard and new ply both have a full bearing. I hope to do the other end of the room another time (it is the dining end of a k/d, and there is a half-height partial partition). the kitchen end is about 3150 long so i can't get both cut ends under a unit and at the partition and I can't move the partition because it aligns to steps.

so far I have found two pairs of sistered joists, don't know why, but, annoyingly, the joist spacing seems to have been maintained so that a 2440 board cannot not stand on a joist at each end. the old floor was built hoping the T&G would support the short ends (it didn't) which is why I am replacing with ply. I will cut it to place one square end just under the edge of the end kitchen units, which is OK, and one on a sistered joist which is the best i can manage. My joinery is inexpert so I will probably have a visible gap at the cut which I will try to fill in some way before putting down vinyl.