Green Building Forum - Lime plaster breathable wall Macpherson Eclipse Emulsion

Lime plaster breathable wall Macpherson Eclipse Emulsion

mzthomps — Sun, 20 Aug 2023 19:33:53 +0100

I have just renovated internal walls with breathable insulation - diathonite| wood fibre| diathonite| lime. Is Macpherson Eclipse Emulsion suitable as a mist coat? It claims high permeability, but I can't track down the SD value or any reference to lime. Does anyone know any better? Many thanks. This is the link to data sheet: https://www.paint-direct.co.uk/content/documents/products/132700235123271550-macpherson-eclipse-emulsion-technical-data-sheet.pdf

Lime plaster breathable wall Macpherson Eclipse Emulsion

Peter_in_Hungary — Sun, 20 Aug 2023 20:03:05 +0100

Posted By: mzthompsI have just renovated internal walls with breathable insulation

Do you mean you have insulated your internal walls or have you put internal insulation on your external walls (IWI) ?

Lime plaster breathable wall Macpherson Eclipse Emulsion

djh — Sun, 20 Aug 2023 20:52:57 +0100

Assuming you mean you put internal insulation on your external walls (as otherwise it doesn't matter too much once the lime is fully dry), the accurate answer is I don't know!

But, taking a SWAG, it seems to have a similar list of ingredients to Dulux Supertrade Matt so probably is permeable. We used the Dulux because they did use to publish an SD value, but I can't find one now. So it's always possible they've changed the formulation. But both paints are advertised for use over newly-applied plaster so it would be very surprising if they weren't fit for use. We used a clay paint for the top coat, FWIW.

Lime plaster breathable wall Macpherson Eclipse Emulsion

mzthomps — Sun, 20 Aug 2023 21:16:05 +0100

Thanks. Yes - the inside of the two external walls (mid-terrace).

Lime plaster breathable wall Macpherson Eclipse Emulsion

tony — Sun, 20 Aug 2023 22:08:24 +0100

I think that the lime will react with the paint, trying to paint stripper it causing some problems. Lime is highly alkaline.

Lime plaster breathable wall Macpherson Eclipse Emulsion

djh — Mon, 21 Aug 2023 10:29:47 +0100

Posted By: tonyI think that the lime will react with the paint, trying to paint stripper it causing some problems. Lime is highly alkaline.

I doubt it, TBH, but if there is any doubt then try a small inconspicuous area first. Or of course use limewash instead.

Lime plaster breathable wall Macpherson Eclipse Emulsion

mzthomps — Tue, 22 Aug 2023 15:15:06 +0100

Crown have now confirmed that Eclipse is not suitable to be used on lime. Requires a mineral based coating.

Lime plaster breathable wall Macpherson Eclipse Emulsion

kristeva — Sun, 27 Aug 2023 08:09:18 +0100

Posted By: mzthompsI have just renovated internal walls with breathable insulation - diathonite| wood fibre| diathonite| lime. Is Macpherson Eclipse Emulsion suitable as a mist coat? It claims high permeability, but I can't track down the SD value or any reference to lime. Does anyone know any better? Many thanks. This is the link to data sheet: https://www.paint-direct.co.uk/content/documents/products/132700235123271550-macpherson-eclipse-emulsion-technical-data-sheet.pdf

The problem with using emulsion on lime is acidity. Farrow & Ball Estate emulsion has an SD value similar to lime wash but there technical department once told me the pH value of the lime plaster should not exceed '10' otherwise the paint would likely peel off. NHL plaster usually dries to a ph level of between 8 - 9, I would imagine lime putty based plaster to be higher.

Lime plaster breathable wall Macpherson Eclipse Emulsion

Peter_in_Hungary — Sun, 27 Aug 2023 09:18:22 +0100

Over here there are a number of brands of lime based paint for walls that are advertised as breathable and about the same price as ordinary paint.
A quick search for the UK gave
https://organicnaturalpaint.co.uk/natural-paint/lime-paint/
and
https://www.celticsustainables.co.uk/paint-for-lime-plaster-internal/
although both stocked Auro paint among others so probably worth a better search for lime based paint which should be compatible with the lime on the walls. Ask the manufacture.