Shiplap Cladding Gaps - help !

[MenBehavingBadly]

So I was very proud of my new shed - for about a week

And then I noticed that gaps were opening up between the shiplap presumably as the wood dried out - my bad for not leaving the wood long enough to dry out before fitting

I installed it with 1.5mm gap but some of the gaps are now 6mm and I'm guessing these will leak (and may get bigger)

I'm pretty much resigned to moving the boards around and closing the gaps up - luckily I screwed the boards on so easy to remove - on 3 sides at least

So couple of questions

1) Shall I leave it a few more weeks so it dries further - then refit with a 2mm gap maybe - or do I need to wait longer ?

2) Is it worth putting some breathable waterproof membrane on under the cladding ? Its "only" a shed but I do want it waterproof - any suggestions for what to use ?

Funny the old shed I replaced was a cheapo kit build and that never leaked - until the felt on the roof rotted

Thanks

 

[Koolpc]

I would leave them much longer.

 

[Koolpc]

Good info here:

 

[MenBehavingBadly]

That makes me glad I screwed them in

 

[freddiemercurystwin]

If you want waterproof cladding you need a breathable membrane on the outside face of the studs, then vertical battens, then the cladding. Any old cheap breather membrane off ebay will do for a shed.