Hi Folks,

Read with interest the advice here:

https://www.woodworkforums.com/f11/bl...do-i-do-39050/

and had a few questions for the group.

We have a standard timber fence out the back (22.5m), palings on our side. Located in Brisbane, so plenty of sun and rain. We'd like to install 1200 x 1800 x 7.5mm blueboard, so that a rendered finish can be applied (e.g. roll on one like DULUX Fine Texture).

I've looked @ the various jointing systems, and am leaning toward Cemintel External Jointing Compound and Cemintel External Jointing Tape PVC Perforated. Would the perforated tape be better for this application?

Great vid here btw:
installation

We'd have around 3mm between sheets, and expansion joints every 6m using Trim-Tex Hideaway Expansion Joint.

I realise it would be ideal to have 1800H CCA pine (100 x 38) rails for the back of the (vertical) joints, but can we get away with, say 4 horizontal rails? Is there some sort of weather proof gasket tape that I could apply at the back?

Without the vertical rails, the joint would be exposed from the rear.

Also, would there be any requirement to seal the (exposed) rear of the blueboard (to help preserve the render finish)?

Regards,
JPS