Limewash
Limewash is a traditional paint, which is simple and cheap to make. It has several benefits over modern paints, particularly for the restoration or repair of historical stone properties. Limewash allows old buildings to ‘Breath’, a necessity for monolithic walls which are designed to absorb and release moisture through changing conditions.
Limewash also has a unique depth of tone and unique finish, which is difficult if not impossible to achieve with modern paints.
Where to Use Limewash
Limewash should only be used on mineral substrates such as:
- Lime Plasters and renders
- Lime and cement based mortars
- existing limewashed areas
- Clean Brick, stone, terra cotta and cement blocks.
Where NOT to Use Limewash
Limewash is not suitable for:
- Gypsum Plaster or plaster board
- Previously painted or varnished surfaces
- Wood (causes the grain to swell)
- Smooth or non-porous surfaces
Weather Considerations
Limewash needs to cure and external applications will require several weeks of dry weather, with temperatures above 7 degrees. Rain will cause streaking, although it is possible to protect limewashed surfaces from rain or sunny conditions by hanging hessian sheets. Leave a gap between the hessian and the limewashed surface to aid air circulation. In sunny or hot weather conditions, the hessian should be regularly sprayed with water.
Safety Information
Lime is a caustic substance so gloves and eye protection should be worn at all times. Suitable clothing should also be worn to avoid contact with skin.
Recipe
Primer Coat – for walls with no previous coating
- 12 parts water
- 1 part lime putty
Wash Coat
- 1 part Lime Putty
- 1 part water
- Pigment *
1. In a large bucket with plenty of headroom, make the wash by mixing 1 part lime putty with 1 part water
2. Dilute the pigment with a small amount of hot water.
3. Add the pigment solution to the limewash* and mix in well.
Optional additives
There are several additives available to improve the finish and strength of the limewash, whilst retaining the breathability:
• Boiled Linseed Oil (maximum 1%)
• Acrylic Binder
• Alum Fixative (maximum 100g per litre).
Always add the same quantity of additives to each coat.
Application
Lime can be hard on tools so put away your best brushes. We recommend a 4 inch (100mm) synthetic hair brush.
Ensure the wall is clean and free from dust. Mist with surface with water, to avoid rapid absorption which could cause a powdery finish.
Make sure you mix the wash regularly to ensure the particles stay in suspension.
Start with the primer coat. To ensure even coverage, work the wash into the wall using a criss-cross brush stroke pattern.
Be sure to blend-in any runs or lines as they will show through the top coats if left. You can use a brush or a damp sponge to do this.
Using the same brush pattern as the primer coat, apply the wash. We recommend you apply 4-5 thin coats for external walls. For internal walls you can apply as many or as few coats as necessary, to achieve the required finish.
*To maintain the strength and breathability of the limewash, pigment weight should not exceed 10% of the lime putty weight used. e.g. if you used 10 kg of lime putty for your limewash mix the pigment weight should not exceed 1kg.