moisture barrier on or under battens?

[happyolly]

Hi,
We've built a workshop from Xella, Ytong blocks (7n/m I think).
It will be clad with shiplap or featheredge weather boarding.
We're using 25mm deep battens to nail the weather board to and have decided against any further insulation.

Where should the moisture barrier go please.
Between the blocks and the battens or the weather board and the battens?

I'm fairly sure it's the former to allow air to circulate round the back of the boards and the battens to dry them out if they get wet but my dad's convinced he's read otherwise.

Thanks

 

[s60tsy]

id do membrane/batten/board

 

[Blagard]

Maybe you should point your dad to this as just one of many examples s60tsy is correct


http://www.highcastle.co.uk/construction/our-prefabricated-timber-frame-panel-system-specification/

 

[happyolly]

I don't know how important it is to the discussion but we will be using breathable membrane that we have left over from doing the roof.

Some of the stuff I've seen on the net appears to distinguish between a vapour barrier and a breathable membrane.

 

[geraldthehamster]

Some of the stuff I've seen on the net appears to distinguish between a vapour barrier and a breathable membrane.

That's because they are two different things.

A vapour barrier goes on the warm side of any insulation to prevent moisture in warm air condensing on cold material.

A vapour barrier goes where has already been said, to enable moisture that penetrates from any direction to get out again.

Cheers
Richard