Render onto wood frame extension

I'm into a fairly large extension all in wood frame. The structure is from inside to out:

Plasterboard
25mm service cavity
vapour barrier
9mm OSB
89mm stud wall
100mm cavity (stud and cavity filled with warmcell)
89mm stud wall
9mm OSB
Breathable membrane

I want to render and I am looking for the best solution. I want the render system ideally to tack straight to the breathable membrane with some kind of mesh I guess, render base and top coat. I have considered counterbatten, render board etc but the overall render system thickness becomes an issue.

Being timber movement is a bigger issue than brick/block

Cheers

Rich

you need EML, expanded metal lath, and you want to use s/s for longevity. perosnally i like the counter batten and then cement board with eml over, is is more durable and not so damaging to your property should it ever need removing it also leaves a clear air circulation gap.

1john said:

you need EML, expanded metal lath, and you want to use s/s for longevity. perosnally i like the counter batten and then cement board with eml over, is is more durable and not so damaging to your property should it ever need removing it also leaves a clear air circulation gap.

Click to expand...

Thanks John.

Yes EML stainless is probably the route to go. Ideally I would go for batten and board but that'll be 35mm before the actual render. I want to keep the thickness down as much as possible as the breathable membrane is flush with the lower brickwork. In an ideal world the wooden suds would have been set back to the bricks to allow for the batten and board.

I suppose you could use a 5mm lath to space the boards out and still have an air gap/be able to remove in the future.

Cheers

Rich

cant see a 5mm gap not getting filled to be honest with you unless you mean to space cement boards 5mm off the outer skin? if so then this is a possibility.

1john said:

cant see a 5mm gap not getting filled to be honest with you unless you mean to space cement boards 5mm off the outer skin? if so then this is a possibility.

Click to expand...

Yeah - that's what I meant space the render boards off the outer skin by 5mm.

How thick is render overall usually?

Cheers

Rich

In the end went for Renderlath system on 25mm battens

I closed the base of the air gap with stainless beading to enable venting nd to stop insects and rodents