Fixing/stapling breather membrane on Wood Fibre

[BenP]

Hi, 

 

We're about to start fixing our breather membrane onto our wood fibre insulation sheathing board. Fixing advice from Pro Clima suggests stapling the top layer and then taping the overlap from the above layer. On the walls however, the staples (sized as advised) just have no hold on the insulation board. The roof sheathing board is much better. 

 

What am I doing wrong?

 

I'm not expecting a solid result just enough to hold it in place until I tape the above layer and ultimately put my vertical fixing battens against it...

 

Cheers.