Limewash is back in the limelight

If you're looking for that extra touch of class, traditional limewash could be the answer. It's been around since Roman times and it's proving its worth these days on projects across the country, especially in the booming renovation market.

Limewash offers an inexpensive protective coating, but there's a lot more to it than that. As it ages, it develops a patina unrivalled by modern paints and renders, and it actually allows the fabric of a building to breathe.

So, to make sure you're not missing out, here's everything you need to know about getting the best from this classic coating.

How is limewash different from paint?

The key difference is that it doesn't form a plastic-like film over a surface.

Limewash is a suspension of tiny particles of calcium hydroxide. These particles embed themselves into the surface of what's being coated. When the limewash dries, the calcium hydroxide reacts with carbon dioxide in the air to form minute crystals of calcium carbonate (chalk) within and on the surface.

Also, it's far more permeable to water vapour than modern paint, so it won't trap moisture in the building fabric. And the crystals give a delicate warm finish, which is far better to look at than the flat, featureless colouring of 'film-forming' paints.

Limewash is also more environmentally-friendly than paint. It's developed from an abundant natural mineral. There are no toxic compounds or solvents - and no toxic waste. Because it reverts to chalk, old limewash material can be beneficially returned to the soil.

Where should you use limewash?

You can use it on render, plasterwork and masonry on internal and external walls.

Clearly, given the way limewash works, the surface of what you're coating needs to be porous, something like sandstone, clay bricks or lime plaster.

Where shouldn't you use it?

It's generally not suitable for use in heavily trafficked areas, such as busy corridors and stairs. Properly applied, limewash shouldn't rub off onto clothes. But it will wear out far more quickly if people are constantly brushing against it.

Also, don't try it on surfaces that contain waterproofing materials, or on dense impermeable substrates such as concrete (unless it's been given a suitable primer).

Is it still the stuff the Romans knew?

White Peak, the limewash from Buxton Lime, is exactly the same recipe, just purer and finer.

And only mineral pigments - the traditional stuff - go in to make White Peak's range of colours.

Why choose White Peak?

The best limewash is made from the purest high quality lime, the type found in the area around Buxton in the Derbyshire Peak District, where Buxton Lime is based.

By combining the special qualities of lime and modern know how, Buxton Lime has produced a limewash in a class of its own.

White Peak Finest Buxton Limewash contains ultra-fine particles, up to 100 times smaller than you normally get in limewash. The finer the particles, the greater the range of surfaces you can apply it to, and the denser and more durable the finish. Finer particles also mean the limewash is more stable, so there's less stirring and a more consistent finish. And you can use denser pigments to colour the limewash.

What about colours?

Limewash will harden white when it's applied without a pigment. Just how white depends on the purity of the raw material. White Peak offers an exceptionally brilliant white.

It's also available in 25 ready-mixed authentic colours. These can be used neat to replicate rich and deep historic colours, or as concentrates to produce more delicate colours when mixed with white.

Do the colours last?

White Peak's colours are stable, but weathering will change the appearance of a limewash subtly and gradually. It develops an attractive patina, without the blistering and peeling you get with modern paint. Depending on what it's exposed to, limewash will need to be renewed every five to twenty years.

An internal limewash will last much longer and, like paint, will usually be renewed because it gets grubby or the customer wants a change.

How do you apply it?

First you need to stir the limewash to a creamy consistency. White Peak, of course, needs less stirring because of its quality composition.

Old backgrounds should be washed to remove dirt and grime, new surfaces should be allowed to dry and cure properly.

Dampen the surface of what you're coating with clean water. Then apply the limewash as evenly as possible with a long-haired bristle brush, working it in well. Cover 3-4m2 at a time, then finish off by 'burnishing' - using a dry brush in a circular motion. Brushes can be washed after use in clean, running water.

White Peak can also be applied by a heavy weave type roller.

Limewash is semi-transparent when it's first applied. That's normal, so don't try to build up the finish in one thick coat. It will only craze and crack as it dries. Allow the first coat to dry fully before applying the second and so on, lightly dampening the background before applying the next coat. It will harden and the colour will fix as the limewash reacts with the air, to create those tiny crystals mentioned earlier.

Applied properly, limewash will produce a delicate, vibrant finish. But differing surface textures will reflect light in different directions and the finished result may appear patchy. If you're not sure, test the limewash on a suitable area first.

On a flat porous surface, one litre of White Peak should put three coats over 3-4m². The application rate should be about 20m² an hour.

White Peak is available in 1-litre, 5-litre and 10-litre containers from stockists across the country. Contact Buxton Lime or visit www.whitepeaklimewash.co.uk

What about safety?

Calcium hydroxide, the central component of limewash, is a natural product. But it's also highly alkaline when wet and can be hazardous, particularly to your eyes and skin. So you need proper protection - goggles, gloves, and long-sleeved overalls - whenever you're using it.

Still want to know more?

Buxton Lime is the UK's leading supplier of lime and lime products. It has been involved in producing lime in Derbyshire for more than a century. For full details on its product range and stockists, contact us on tel: 01298 768555 fax: 01298 72195 e-mail: buxtonsales@tarmac.co.uk