This white coating promises to refresh worn-down brick exteriors and protect them from the elements—but it's not for every homeowner. Think your home could use an update? Consider the pros and cons of this DIY treatment, and follow the easy steps outlined here.
A walk through of one of the many ways to apply Portola's Lime Wash. Handcrafted professional quality paint brushes formulated for superior results with all paint types. Shorter handle with sculped finger and thumb support to front and back. This site uses cookies to give you the best experience.
Non-toxic garden pot paint. Discover natural limewash paint from Bauwerk Colour. Over 400 unique eco friendly paint colours. Treat the lime wash like stain instead of paint - it will not go on in a thick coat. Work quickly, feathering with each sweep of the brush to avoid obvious stroke lines and moving rapidly to the.
Photo: istockphoto.com
Despite being one of the most durable materials around, brick very visibly ages. Its crisp square edges can soften, and joint repairs on brick siding can leave noticeable imperfections. Even if your brick remains in great shape, the color or shade of the building blocks may now make your house look drab and dated (remember the orange bricks of the ’80s?). Before you grab a bucket of paint to cover any of these blemishes, consider the benefits of an alternative, time-honored coating: limewash.
This application produces a soft white façade that improves your home’s curb appeal while adding a measure of protection against the elements. Unlike some types of brick updates—such as tuckpointing or repointing, which should be done by professionals—limewashing is an accessible project for do-it-yourselfers and inexpensive to boot! If you’re thinking about changing the look of your bricks, keep reading. We’ll run through the basics of limewashed brick and share a simple method for getting this look at home.
Limewashed Brick Basics
Limewash is made from powdered limestone that has been treated with heat and water to change its chemical composition, resulting in a stable product that provides a durable coating when applied to porous brick. The terms “limewash” and “whitewash” are often used synonymously, but while limewash is a specific type of whitewash, other types of whitewash do not use lime as an ingredient.
Like other popular brick-coating treatments, such as German Smear, limewash has its roots in antiquity; it was used centuries ago to protect structures from the weather. Both coatings add a thin layer to the outside of the structure, which helps protect the bricks and mortar from the elements. Buildings that were coated every few years developed a durable layer of protection against rain, wind, and harsh sun rays.
In most regions of the world, limestone deposits are plentiful. Therefore, because true limewash contains just lime and water, its use was very accessible and commonly used in the protection of ancient vernacular architecture. Its ability to protect brick, block, and other types of porous material (including adobe, clay, and terracotta) made it invaluable for coating structures dating as far back as ancient Egypt, where it was used it to coat temples and monuments.
Today, limewashing is a staple in the historical restoration industry as well as being a cherished method for updating the look of exterior (even interior) brick on homes. You can find it on commercial buildings and residential houses in all price ranges throughout Europe and the United States, and it’s just as at home on a castle as it is on a cottage.
Photo: Zillow Digs home in Newberry, SC
Pros and Cons of Limewashed Brick
Like all coatings, limewash has its pros and cons. Weigh them before you commit to this exterior update, but know that it can be scrubbed away later if you decide.
Pros:
- Limewash is inexpensive. A whole house can be coated for $10 to $80 in supplies. If you can find hydrated lime locally, which has already been treated in a pressure hydrator and only needs to mix with water, it’s as cheap as $3 to $5 per 50-lb. bag (of which you’ll need two). If you order it online, you can expect to pay about $40 per bag—an upcharge mostly due to high shipping charges.
- Limewash coating is natural and environmentally safe—a “green” choice.
- Applying limewash is DIY-friendly. See below for how to get started!
- Limewash, which is highly alkaline, resists fungal growth and insect damage.
- Subsequent coats of limewash can be applied over existing coats.
- The coating won’t peel off as paint-based coatings can.
- A layer of limewash offers protection against weathering.
Cons:
- Limewash will erode over time, requiring renewal coating every five to seven years.
- The solution should be applied on overcast days to keep from drying too quickly.
- When dry, limewash may rub off on clothing.
- For coating siding, limewash should be mixed in large batches to avoid batch discrepancies. Because the exact ratio is difficult to duplicate precisely, smaller batches may be slightly different, which can result in noticeable lap marks on the limewashed brick wall when the solution dries.
- Limewash will not adhere to previously painted bricks.
Photo: istockphoto.com
Get the Look
The following method for mixing and applying limewash is simple and will produce good results. We’ll be using two 50-lb. bags of hydrated lime, which is ready to mix with water. While other types of lime, quicklime, and lime putty are also available, quicklime is not hydrated (which is necessary for making limewash) and can cause severe burns. Lime putty is less dangerous to work with but requires aging before it can be made into limewash.
MATERIALS AND TOOLS Available on Amazon
– Hydrated lime
– Dust mask
– Goggles
– Gloves
– Water
– Bathroom scales (optional)
– Large paint brush or paint roller
– Large plastic bucket (with tightfitting lid)
– Smaller bucket or roller pan
– Drill with paddle bit (or a stick)
Before mixing or applying limewash, clean the bricks.
Spray down brick siding with a water hose to remove dirt and dust buildup. If you have any especially dirty or grimy areas, spray them with an all-purpose cleaner, scrub them with a stiff nylon brush, and then rinse the area with a hose.
Safety first.
Lime is caustic and safety precautions must be taken not to inhale the powder or get it on your skin. Put on a dust mask, goggles, and gloves before mixing the limewash solution.
Photo: istockphoto.com
The most important part of limewashing is getting the solution right.
When mixed correctly, limewash should have the consistency of whole milk. Remember, this is a wash, not a paint. It shouldn’t be thick and gloopy.
The correct ratio is approximately 80 percent water to 20 percent hydrated lime (by weight). You can make larger or smaller batches as long as you maintain that approximate ratio. If you’re making a small batch, feel free to use old bathroom scales to weigh the ingredients. To mix an entire 50-lb. bag of hydrated lime (enough to coat a typical 1,600 sq. ft. ranch-style house), you’ll need 30.5 gallons of water. One gallon of water weighs 8.33 lbs. so 30.5 gallons weighs approximately 250 lbs. A 50-lb bag of hydrated lime weighs 1/5th or 20 percent as much, which will give you an 80:20 water-to-lime ratio.
Small batches can be mixed in 5-gallon buckets, larger batches (such as the recipe for a whole bag above) can be mixed in large, heavy-duty plastic trash cans, and then transferred to smaller buckets or roller pans as needed. It helps to have a drill with a long paddle bit to mix the solution but a long stick will do just as well if you take your time and stir the solution thoroughly.
Pro Notes: Unused limewash solution can be saved for a few weeks if it’s tightly sealed to prevent evaporation of the water in the mix. Cover the bucket or trash can with plastic sheeting before putting on the lid. You can use the same batch of limewash for a second coating, just make sure to mix it well again before applying.
Choose an overcast day to apply limewash.
Limewash is the most durable when it dries slowly; a hot sunny day can cause it to dry too quickly. You can also slow down drying time by dampening the bricks before application. Just spray them down with a water hose and wait five to 10 minutes before applying the limewash.
Apply the limewash just as you would paint.
Transfer a workable amount of solution to a small bucket or a roller pan and use a paintbrush or a paint roller to roll it onto the bricks. Start at the top of a wall on one side and work across and downward in 4- to 5-foot swaths. The lime solids have a tendency to settle to the bottom, so stir as you go (and thoroughly before reuse). Don’t be alarmed if you can see right through the mixture as you apply it—it will whiten as it dries. Cover all the bricks evenly, and then wait two to four days before applying the next coat. Each additional coat will make the surface opaquer. Three to four applications may be necessary to reach the desired opaqueness.
Maintaining the Look
- Surface stains on limewashed brick can be removed by rubbing lightly with a damp rag.
- Limewash coating can be removed with a pressure washer, or by hand, with a bucket of water and a stiff nylon scrub brush if you grow tired of the look.
- Finished limewash will gradually erode, which can produce a very attractive weathered look, but to retain the original opaque coverage, reapply the limewash every five to seven years.
- There is no need to remove existing limewash in order to apply renewal coats.
Related Products
Lime Patina and Limewash Recipes
This how-to covers the basic principles for preparing and applying limewash, along with recipes for the Primer coat, Wash coat and Patina coat.
Choosing Lime
This article contains two recipes: one using dry lime powder, and one utilizing wet lime putty. Dry lime powder refers to our High Calcium Hydrated Lime. This is a high quality, high purity dry lime powder. It is not the same as agricultural lime from a garden center. Lime Putty refers to wet lime in a bucket. This includes both pit lime from a factory and Hydrated Lime powder that has been slaked by the consumer.
Hydrated Lime should be a bright white powder, not more than two years old. We carry the purest, highest purity food grade High Calcium Hydrated Lime.
Lime Putty should be stored in a sealed bucket with at least 1 inch of water on top of the putty to protect it from exposure to the air. In cases where the substrate is very tightly bound, or when the greatest transparency is desired, factory produced Lime Putty is preferable over powdered lime.
Choosing a Suitable Surface
For lime to properly adhere to a surface the two must be:
- Chemically compatible
- Mechanically compatible
When it is chemically compatible, lime will not adversely react with the surface, causing the two to separate, (the lime flakes or falls off). When mechanically compatible there is sufficient porosity and texture – often referred to as 'key' – to allow the lime crystals to expand, 'lock' onto and penetrate the surface.
Limewash has rigid requirements when it comes to suitability with a surface because it is a thin coating. As with lime plasters, the supporting surface must be able to withstand a pH of 12 or more.
Surfaces suitable for limewash include:
- Lime
- Lime plaster and renders
- Lime and cement based mortars and renders that have proper tooth and porosity
- Previously lime washed supports
- Masonry supports such as, brick, stone, terra cotta (mud) and cement block
Surfaces that are unsuitable for limewash:
- Asbestos cement (chemically incompatible)
- Dry wall (porosity inconsistencies and chemical incompatibility)
- Hard troweled renders and plasters (too hard for lime crystals to penetrate for bonding)
- Gypsum Plasters and products (chemically incompatible)
- Previously painted or sealed surfaces (lack of porosity, chemically incompatible)
- Smooth surface or nonporous surfaces (no porosity, no room for lime crystals to penetrate for bonding)
- Wood (too high in PH, will cause wood grain to swell)
Alternative for Unsuitable Surfaces
Commercially prepared acrylic reinforced lime washes with compatible primers are often the only alternative for surfaces such as previous paint. Gypsum plasters are not compatible with lime wash, but they can accept Casein based paints such as Milk Paint and Casein Borax Paint. These paints are translucent and can create the matte appearance of lime wash.
Proper Atmospheric Conditions for Application
Conditions for application are the same as for lime renderings. Proper temperature and humidity are required for the carbonation process to be successful – the most critical period for carbonation is the first two to three days.
- Ambient temperature should not be below 41 ºF (46 ºF for dark colors) at any time during the application or carbonation process. Do not allow freezing to occur.
- In temperatures above 86 ºF or in very low humidity, surface and subsequent coatings must be misted with water.
- Exterior coatings should be protected from wind and sun to protect it from drying too quickly. An opaque covering such as damp canvas or burlap works particularly well.
- Surfaces must not have a surface temperature below 41 ºF (46 ºF for dark colors) and must not be excessively hot or excessively wet.
Preparing Suitable Surfaces (Lime and Masonry)
First, the surface must be fully set. Very smooth surfaces that don't have enough tooth (roughness) for the lime to bond with may require texturing with medium abrasives or a wire brush. Dust and loose debris should be removed by brushing or dusting, and then washing.
Second, the surface must be assessed for the proper dampness. A light dampness is desired – too much moisture on the surface will interfere with cling and coverage. Dampness can be influenced by the porosity of the surface, as well as humidity and temperature. It shouldn't absorb the primer, wash or patina coat so quickly that it dries almost immediately after being applied. It also may be necessary to mist before subsequent coats are applied. Misting, (prewetting) can easily be accomplished using a plastic spray bottle, pump sprayer or, on exterior projects, a garden hose with a suitable mist nozzle.
Mixing Instructions
For mixing, use a plastic bucket with lots of 'headroom'. Since lime is caustic, it can cause 'burns' to skin and eyes. Make sure you wear suitable clothing, (long sleeved shirt & long pants, cover-alls, etc.) rubber gloves, shoes and eye protection.
Slowly add powders, (lime, pigment or additive) to water, not water into powder to minimize dust. Avoid inhaling airborne powder during mixing and USE A DUST MASK! Mix only the amount of limewash to be used in one day. Larger quantities should be mixed with a paint paddle mounted to an electric drill.
How To Paint Limewash
Additives (Binders) for Enhanced Adherence
Within the limewash recipes, there are suggestions for additives (additional binders) to enhance the adhesion of limewash. They won't alter the appearance or breathability of a limewash, and since they provide additional insurance your limewash will be successful are highly recommended. One important rule: always add the same ratio of additive for each successive coat. Additives are important in exterior applications due to weather exposure. Additives are important in interior applications as well as a limewash that powders off in an interior space is not healthy.
Application Techniques
Choose brushes made specifically for limewash, or a 4' Poly/Nylon paint brush. A sponge can also be helpful to apply patinas and soften brush marks if desired. Lime is hard on tools – be sure to rinse all brushes thoroughly after use and hang to dry as the metal of the ferrule will be prone to rust. You may need to 'retire' several brushes over the course of a large project.
Lime and/or pigment particles will NOT remain suspended in water for long and MUST be frequently agitated. This is very important! During application of the Primer Coat, a paint stir-stick should be used at regular intervals. During application of wash or patina coats it is best to transfer portions of your freshly agitated mixture to a shallow container so that your brush bristles can touch the bottom and with each pass of the brush you can sweep the lime and pigment particles back up into suspension.
Lime wash should be worked down into the surface using a brush in a cross-hatch motion (also known as figure eight or butterfly.) This creates a more pleasing appearance than using a simple up and down motion with the brush. Brush marks can be left on the surface for added interest, or can be blended with the brush or by the use of a damp sponge. Sponges can also be used to apply a different color to specific areas, usually in the Patina Coat.
Several thin coats are the key to success – never apply too thick. For exteriors, 5 coats are recommended. For interiors, 3 coats or less depending upon the effect desired.
Fresco Application Technique
In the Fresco technique, limewash is painted onto fresh, set, wet plaster. This technique requires that the surface be hardened enough so as not to deteriorate as it is being brushed, but not too dry as to inhibit proper adhesion of pigments with the lime in the surface. Technique and climatic conditions play a major factor in application success. Read a detailed discussion of the Fresco Technique.
Limewash Recipes Using our High Calcium Hydrated Lime
This limewash recipe is broken down into three parts: a Primer Coat, a Wash Coat, and a more translucent Patina Coat.
Primer Coat
- 20 parts water
- 1 part High Calcium Hydrated Lime
Wash Coat
- 6 quarts water
- 1 kilo package Earth Pigments High Calcium Hydrated Lime, (approx. 1½ quarts by volume)
- Up to 500g Ocher or Pigment
- Additive¹
Coverage estimate is 110 sq feet dependent upon absorbency of substrate.
Patina Coat
- 12 quarts water
- 1 kilo package Earth Pigments High Calcium Hydrated Lime, (approx. 1½ quarts by volume)
- 800g Ocher or Pigment
- Additive¹
Coverage estimate is approximately 220 sq feet.
Limewash recipes using Lime Putty
This limewash recipe is broken down into three parts: a Primer Coat, a Wash Coat, and a more translucent Patina Coat.
Primer Coat
- 12 parts water
- 1 part Lime Putty
Wash Coat
- 1 quart water
- 1 kg Lime Putty
- Pigment²
- Additive¹
Patina Coat
- 2 quarts water
- 1 kg Lime Putty
- Pigment³
- Additive¹
Coverage estimate is approximately 220 sq feet.
Recipe Notes
1. Additives are used to promote adhesion of the wash or patina coats, (you must use the same additive for all coats of Wash and Patina).
- Boiled Linseed Oil: ½ cup, OR
- Earth Pigments Acrylic Binder: ½ cup, OR
- Casein Powder 100g (interior only)
Limewash Exterior Paint
2. Pigment amounts when using Lime Putty:
- Natural Earth and Ochers: up to 250 grams
- French Mineral Pigments: up to 250 grams
- Colonial Naturals: up to 250 grams
- Oxide Pigments: up to 150 grams
3. Pigment amounts when using Lime Putty (Patina Coat only):
- Natural Earth and Ochers: up to 500 grams
- French Mineral Pigments: up to 500 grams
- Colonial Naturals: up to 500 grams
- Oxide Pigments: up to 300 grams
Final thoughts
How To Limewash
The subject of lime coatings is more extensive than is presented in this short article but we hope this information will help you understand the basics. Application techniques, variations in lime types, and the many possible visual effects make limewash a fascinating topic for further research and experimentation.
Related Instructions
Fresco & Patina Application for Lime Plasters
Efflorescence in Colored Concrete and Stucco