Plastering: How should the ply be treated to ensure a good lasting finish? Ask your questions and find answers on many subjects relating to plastering and dry lining

[Terry]

I have formed arches ussing 3mm. ply curved around a timber frame in each corner of a cavity wall which was previously knocked through to form an extension.
I am having a skim coat applied over the existing plaster and aws concerned that the plaster may not take to the ply.
How should the ply be treated to ensure a good lasting finish?
Please advise

[Terry]

I have formed arches ussing 3mm. ply curved around a timber frame in each corner of a cavity wall which was previously knocked through to form an extension.
I am having a skim coat applied over the existing plaster and aws concerned that the plaster may not take to the ply.
How should the ply be treated to ensure a good lasting finish?
Please advise

[omulcol]

[quote="Terry"]I have formed arches ussing 3mm. ply curved around a timber frame in each corner of a cavity wall which was previously knocked through to form an extension.
I am having a skim coat applied over the existing plaster and aws concerned that the plaster may not take to the ply.
How should the ply be treated to ensure a good lasting finish?
Please advise[/quote]

There are two ways to tackle this problem.
First, is to staple EML ... or expanded metal lath over the ply and timber, and scratch coat over it using Carlite Bonding - then skim over with MultiFinish.

The second alternative is to apply two coats of neat PVA plastering adhesive over the timber - allowing the first to dry - applying the second coat immediately prior to skimming.