Is limewash a good base for three coat plaster?

[inwood]

I need to lime plaster a wall which has been limewashed in the past (originally it was an outside wall). Besides being a bit dusty the limewash is in good condition.

Does this provide a good key for a three coat plaster? (scratch, devil, top) or would I need to rough the surface up to give a good key for the scratch coat? (since the limewash surface is fairly smooth)

 

[Gervase]

How does the limewash sound when you tap it? if it sounds hollow it's best to give it a really good raking with a devil float (and then watch most of it fall off!) If it's firmly stuck to the wall with no hollowness, then just brush it down with a stiff brush to get the dust and any loose stuff off, then wet it with limewater or dilute limewash and apply the plaster.
Any doubts, however, give it the rough treatment. Whatever path you take, though, do use limewater to wet the wall, as this really does help plaster stick to 'iffy' surfaces.

 

[ajbaker]

What is under the lime wash? Plaster or the brick of the wall?

 

[Moreteyne]

Lime on Lime on brick is no problem , just ensure that you rub with a stiff brush to remove any excess flakey bits. Just remember you are sticking to whatever you can see, check for soundness of whatever is below ? ( would also suggest keeping it nice and damp during this warm spell )

 

[inwood]

Thanks all, background is stone, limewash and the pointing below it is very sound and strong.

I will do as suggested, clean it down and apply a fresh coat of limewater and apply the plaster.

Gervase, I'm presuming the plaster should be applied whilst the limewater is still wet?

 

[Nemesis]

All lime plaster should be applied to very wet walls!