Which way round for T&G

[RickH]

I am cladding horizontal ceiling with t&g softwood.
it has v-profile on both sides, so can be fitted either way up.

The board will want to cup in the direction of downwards facing growth rings, so is it best to fit with growth rings upwards so edges pull tighter against the next board, or growth rings downwards to try and pull edges up when you fix

I recall reading there is a right way for T&G but can't remember.


Simplistic sketch attached

 

[opps]

I may be wrong but I thought that you are supposed to alternate them

@JobAndKnock is probably better able to answer than me

 

[Notch7]

it looks best if the cupping happens so the middle of the board cups and becomes proud but the joints stay tight to the ceiling

Timber shrinks mostly in a tangential direction, so if looking at the end of board the growth rings will try and straighten up as the timber shrinks

 

[RickH]

it looks best if the cupping happens so the middle of the board cups and becomes proud but the joints stay tight to the ceiling

Timber shrinks mostly in a tangential direction, so if looking at the end of board the growth rings will try and straighten up as the timber shrinks

Not sure what tangential direction implies, does that mean cup ‘up’. ?