Paint Technical

Dec 8th, 2010 | | Paint Technical | 2 Comments

Limewash versus Paint – An Urban View

Limewash is gradually being replaced by masonry paint in the Algarve. Patrick Baty has recorded its decline over the years

Limewash: Yes!


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Softened by the sun, grappa and holiday spirit it seemed such a good idea to use limewash on returning from the Mediterranean.

Limewash has several winning features but a universal coating it is not. What may work in the Tuscan hills will invariably rebound in South Kensington and any attempt to simulate it on a London exterior will fail. However, in certain cases where the light and conditions are just right, this cheap and relatively simple treatment provides an efficient and attractive means of decoration.

An inappropriate use of limewash on an 18th century house
Limewash: No!


Limewash should not be considered for use over previously painted surfaces or for wood, metal or plastic. Bare plaster, render or brick (in certain circumstances) are the typical substrates that it works best on, but only when one accepts that maintenance will need to be more regular and that a conventional paint system cannot be applied in the future.

Patrick Baty believes that this is both alien to traditional practice and pretentious
“Mock Limewash”: No!


While on a negative theme – please don’t even consider it for your drawing room walls, however much you favour the ‘faded palazzo’ look. If you want that go for a broken colour paint effect using glazes or washes of conventional emulsion. Limewash can be employed in an urban house; indeed we at Papers and Paints receive many enquiries from the owners of such properties. However, its uses are limited. Under no (well, very few) circumstances should the brick façade be painted – one either has unpainted brick which ought to be left as it is or an existing masonry paint on which limewash will not ‘stick’.

On the other hand, a garden wall may well be given a coat or three of limewash and is often the best thing to use on a wall without a damp-proof course. The slightly damp walls of an unconverted basement can also be coated with limewash. The brilliant white nature of the untinted form can help brighten up a grim coal-hole very effectively whilst allowing moisture to pass through it. Similarly, the crumbly brick walls in an unconverted attic can be consolidated and the space lightened with a couple of coats of white limewash.

This was applied in order to catch the light in a new-built glazed extension
Limewash on a Modern Extension


In this example it was used on the newly-plastered walls of a glazed side extension. The crystalline nature of limewash catches the light beautifully and produces a wonderful effect quite different to that of a conventional emulsion paint. However, be warned it does mark easily and cannot be washed down – as the historic tide mark at high-chair level attests.

Only consider the use of limewash if you are seriously committed and have done your research. Don’t expect your painter, let alone builder, to understand what you have in mind. Almost certainly this will be something that you will have to make and apply. However, if you get it into your head that it is difficult you will be surprised at how easy it really is.

There are several companies selling ready-mixed limewash, though as it is over 90% water, consequently bulky and not easily transported it might be worth making it from scratch. The level of commitment required to make it yourself is half the battle and having carried out the necessary homework a more satisfactory result is likely.

The dense clay-like lime putty from which it is made can be obtained from a few specialist suppliers. We have been selling small quantities for over twenty years. This will need to be mixed well with water to the consistency of milk. Naturally white, limewash can be tinted to a limited number of colours, the palette dictated by the few pigments that remain unaffected by its high alkalinity. However, one needs to be fairly relaxed about the exact shade and there is little point in trying to obtain a perfect match. Later reproduction can be difficult and it always helps to make more than is needed. Limewash should be stored in an area free from frost, stirred before use and reapplied when necessary.

Whether bought ready-mixed or home made you must be aware of its caustic nature while wet. It can burn the skin and is dangerous to the eyes. This necessitates the use of goggles and rubber gloves while working with it. If you are not going to apply it yourself it is important that the painter understands the health and safety implications.



A short flim clip that shows how limewash is applied


Limewash does not present the ease, convenience and durability of conventional paint, but if you are prepared to put up with the difficulties of preparation, application and living with it, limewash is a truly remarkable coating of great character and beauty.

ps As an aside, the use of masonry paint is not without it’s own problems, especially if it is applied at the wrong time of year or if unnecessary demands are made of it.


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Comments (2)

Reply
Nigel WattsNo Gravatar » 19. Jan, 2013

Patrick

In spite of your warning that exterior limewash in London “will invariably rebound” I have applied it to my 1840 stucco semi in Islington, having stripped off all the previous paint layers and repaired damaged areas in a lime render. Under the modern paint was linseed oil based paint and under that there seemed to be some limewash. I used a pale copperas, – the CO objected to a darker copperas which I think would have been more authentic – and I like the result.

My builder, however, was a nightmare to deal with. In spite of claiming to be an expert he clearly wasn’t and didnt really know what he was doing, but we somehow managed to get to the end of the work. The windows and railings are done in Invisible Green and I grained the door to look like dark oak.

It is too early to tell how well the limewash will weather.

Reply
PatrickNo Gravatar » 19. Jan, 2013

Thank you for that. By ‘rebound’ I meant from the point of view of aesthetics – the ill-judged attempt to recreate a Mediterranean effect in South Kensington. Of course, it will work on a suitable substrate and I have used it to camouflage a neighbour’s breeze block rear garden wall with good effect.
You may also have seen other posts where I mention copperas, which helps to provide a magnificent finish.
I’m sure with the care and attention that you have put into it your work has every chance of being very effective. I’d love to see a photograph.
Best wishes
Patrick Baty