Rendering over old spar

[s.p.t plastering]

The spar and exsisting render is solid, but the builder wants it flat rendered in s&c, i've never really rendered over old spar, he reckons he's done it before and as long as the spar is sound it's fine, he want's me to put neat sbr on before scratching...Is this ok you think?

I remember a spread i worked with use to dry dash over old spar, just brush all the lose of and weak coat of pva then a butter coat and spar

 

[warriorupnorth]

as long as it's sound it will be fine

 

[spunky]

Use weaker mixes 5-1 and 6-1

 

[s.p.t plastering]

Use weaker mixes 5-1 and 6-1

Yeah! was thinking that spunks.....

 

[Rigsby]

I have hacked off render that has been put on old but sound dashing that has been put on 20+ years ago. I suppose it's down to how good a key it has got.

I would use a neat sbr and cement slurry and go over that whilst wet.

 

[22jasper]

I usually power wash the old dash, stabilise it then lay up and dash - no scratch. Dependant on the stone(pebble,flint,stone) this usually provides a reliable key

If dash is in poor condition,i mesh the whole panel and mechanically fix the scrim before dashing coat.

 

[warriorupnorth]

Like he said the dash/render is sound, so go straight over it , but yes good advice on the jet wash down or/and use an algaecide to kill off any nasties

 

[Render Systems]

just go for it make sure your happy that the dashing is sound,, a quick wetting down will suffice or jet wash if you want wouldnt waste money on sbr 9personally) as the dashing will give a great key