FROM
Linseed oil
Linseed Oil Paint can also be mixed to an emulsion and applied to most types of plaster,
brick or stone walls (internally or externally) or cement floors, but not on lime plaster.
For any wooden surfaces use undiluted Linseed Oil Paint. Emulsion should not be used on any woodwork.From
Lime plaster and oil
You may be onto something with oil over a lime plaster. I don't know much about the compatibility of those materials.
We have one wall here at Emerald Earth where someone put linseed oil over a lime plaster. That reduced the breathability to the extent that
we ended up with mould problems both on the inside and outside surfaces of the wall.
Again, that will be less of a concern on a bench, where permeability to water vapour is not so critical. But you may well end up with black mildew stains on your plaster.
Lime plasters are waterproof in the sense that they do not get soft when soaked, but they are also very breathable.
