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Limewash a good way of protecting softer building materials

Limewash is a very old traditional way of protecting stucco and soft lime renders, particularly those made with lime putty or feeble natural hydraulic lime (NHL 2.5) mixes. Lime wash or calcium hydroxide is basically slaked lime mixed with water.

It is somewhat sacrificial in that it will degrade and slowly break down over time with weather extremities, thus saving the substrate from decay.  Lime wash coating gives protection and beauty to render, plasterwork and masonry.

Lime wash paint can look very attractive on the right type of house

A good quality lime wash can look beautiful, but you wouldn’t want to put it on a modern high rise block of flats. Limewash is a very permeable material allowing walls to breathe, on the right house such as a solid wall cottage, not only will it protect against wind-driven rain it will be in keeping and really enhance the looks of a building. Lime wash contains no solvents or synthetic chemicals. If its a white colour you are after the lime wash produces a brilliant white colour. The additional of pigments produces some very soft attractive colours that just get better with age.

Before the days of sandtex and Dulux weathershield limewash was one of the earliest forms of paint it has been in use for thousands of years. It is a beautiful material which remains attractive as it gradually weathers.

It develops an attractive patina unrivalled by modern paints and importantly allows the building fabric to breathe as it is vapour permeable.
We can specify traditional limewash finishes such as Buxton lime wash. Although lime wash may need a repeated application more than modern paints, we have found it to be one of the most difficult to remove! A good quality lime wash will be efficient at re-carbonation. This is the process in which lime reacts with naturally occurring carbon dioxide, this reaction produces a hardened calcium carbonate film.

Basically, in the process of re-carbonation limewash forms a layer of limestone on the wall. After re-carbonation, the limewash is extremely vapour permeable, allowing any trapped moisture within the substrate to escape. Before limewash can be applied thorough preparatory work has to be carried out, such as disinfecting and removing any organic growth on the walls. The wall may need stabilising and in some cases, hot water jetting. Thin coats of limewash should be applied, avoiding strong drying winds and direct sunlight and of course heavy rain. Time should be allowed between coats, which may be as many as four to five the coats, the rule of thumb is one thin coat per day. Other natural additives can be mixed in with the limewash such as casein ( derived from milk) this can aid water shedding and improve adhesion, also tallow and linseed oil were often added. If you are looking into the restoration of your solid wall property and would like some advice please contact us today

Below a few before, during and after pictures of a grade two listed building before it was lime rendered and limewashed. This soft limestone built house had years of inappropriate materials applied to it such as concrete render and spray on textured plastic coating. To make matters worse (if you could) the front elevation had endured years of ivy growing all over it. The tendrils and roots had got behind the render and were actually growing into the stone wall, feeding on the moisture trapped within it.