Membrane for shed

[Jupiter01]

I want to use a breathable mebrane to wrap plywood (mounted on timber studs), before I put my final shiplap layer on to this membrane. I would leave a void between the membrane and shiplap but don’t have the space, unfortunately.

Is this the recommended order of things?

And what brand of membrane do you recommend for this purpose?

Thanks in advance.

 

[Deluks]

You need the space. You'd be better off putting battens over the membrane and using the ply internally.

Any breather membrane for roof or wall will suffice. The spec isn't as critical as it would be on a pitched roof.

 

[freddiemercurystwin]

If you don't use battens to create a void, the breather membrane may be compromised and fail. They don't have to be very big.

 

[Jupiter01]

If you don't use battens to create a void, the breather membrane may be compromised and fail. They don't have to be very big.

Some more background: this is a lean-to tool shed which is approximately 50cm deep and 4 metres wide. Having the timber studs internally, gives me some extra space for storage. The shed I am replacing has shiplap mounted on timber battens. I thought the ply and membrane would provide some additional protection. Space is at a premium here.

 

[freddiemercurystwin]

Even 1/2" battens would be better than nothing.

 

[Jupiter01]

What’s the risk if I fold the uppermost membrane around the ply? This would mean that there’s no way for the water to enter behind the membrane unless it penetrates through the surface of the membrane, which presumably is a risk even when you have a void?

 

[freddiemercurystwin]

The point of this membrane is to allow any rain or moisture that penetrates the cladding to drip down the back of the cladding/face of the membrane or evaporate away - as the void is vented top and bottom.