plywood against blockwork

[solway]

Hi all. Iv to plaster a new build in the next few weeks.There are a couple of areas externally where plywood is flush with the blockwork.The spec is smooth sand/cement finish.The reason why the plywood is meeting the blockwork flush is because the chippy erected a flat roof finished in fibreglass and made a fascia 500mm .200mm of this fascia is finished in fibreglass and the other 300mm is exposed plywood.The length is 2.5m long. The plywood and block wall are butted together flush so I have to render through both without it cracking along the joint.An expansion joint would look s**t.I suppose my only option is felt,riblathe,fibreglass mesh incorporatd in the render but even this way it could crack.How would ye folks conquer this 1.

 

[kgreigh]

as you've said or could try render board and a flexi thin coat base.?

 

[vfr12]

I had similar job, part of the house, where I had to render over ply. It was Ewi and used eml for the basecoat and fiberglas for the next coat. Never heard back from the customer for any problems. Used Wetherby basecoat, which sticks like s**t. Don't know for sand and cement, but I guess will be the same

 

[malc]

with a piss poor design of ply meeting blockwork. it needs a movement bead fitted a long this joint as it will crack. get an instruction from builder/ designer to cover yourself on this one.