Kiln dried larch decking spacing

[tomincognito]

Will soon be laying larch decking boards, but I'm having trouble committing to an appropriately sized gap. They're kiln dried so I don't imagine they'll move as much as PT, and I've heard larch is fairly stable... Installing now when it's warm and dry, what's the minimum gap you can get away with to account for contraction and expansion? 28 x 145mm, 13-19% moisture. Cheers!

 

[big-all]

you remove spacers so just use plastic or ply and remove
5-6mm but remember iff you have a start and finnish edge you may have to go as high as 7 and as low as 4 but 4 is not ideal iff fully dry timber and 7 not ideal iff very wet