Whitewashing brick fireplaces and home interior/exterior walls have come back in style lately, obviously in response to those of us without a farmhouse or shiplap hiding behind our walls. Whitewashing a fireplace even made an appearance on an episode of Ask This Old House recently!
Classic Whitewashing Recipe
Whitewash, also referred to as limewash, is a very old finishing technique that has been used for centuries around the world. The most recognizable example are the Greek Island villages with their brilliant white exteriors. Paint will never come close to the pure white of limewash.
A basic whitewash recipe is nothing more than a solution of 20% lime suspended in a water solution. High calcium hydrated lime powder is mixed with water and allowed to sit for at least 24 hours to form a thick lime putty. (Lime putty lasts indefinitely as long as there is a layer of water covering it.) Lime putty is then mixed with water at a ratio of 1 part lime putty to 4 parts water to make whitewash. The thin whitewashing solution is then applied to damp brick with a special whitewash brush and allowed to dry for 24 hours before applying the next coat.
Classic whitewash made with only lime putty and water requires at least 3 coats to become semi-opaque with each successive coat adding more brilliance and opacity. It is very easy to apply with a limewashing brush but does take several days and planning around the movement of the sun to complete a project.
Lime + Cement Whitewash
Adding portland cement to the classic lime whitewashing recipe adds body and opacity, requiring only one coat for a semi-opaque finish and two coats for a 100% opaque whitewashed finish over dark brick. The addition of white portland cement adds opacity to the whitewash without taking away from the natural brilliance of lime while also smoothing out the texture of rough brick.
Whitewash vs Paint
Whitewash made with lime is the only way to correctly and permanently lighten brick fireplaces or walls.
Advantages of whitewash
- Odorless
- Inexpensive
- Self healing
- Easily repairable
- Lasts forever
- Durable
- Fills small cracks & holes in mortar
- Chemically bonds to brick
- Antiseptic & antifungal
- Naturally cools homes by reflecting sun’s heat
Do not paint brick
Brick is a natural product that must be allowed to breath. Paint forms a film on the outside of the brick that acts like plastic wrap, trapping moisture between the brick & your walls. Trapped moisture means you’ve created the perfect environment for mold and rot.
Once paint is applied to brick, it can not be reused in anyway, rendering it useless for recycling later. Modern paints are also terrible at holding onto porous materials, thus paint will peel no matter what. From my experience, it starts to peel in 5-10 years. Once you paint brick, it can not be whitewashed properly so do it right the first time and brighten brick with limewash, not paint.
I’ve wanted to lighten up my workshop/garage for a long time since it only gets sun late in the afternoon and use it as my photo studio to shoot all my products. I’ve made do with my moveable shiplap walls but I still had to deal with bricks giving off a red tone in my photos.
I knew I didn’t want to whitewash with latex paint because it was guaranteed to eventually peel and the German smear technique looked like it was such an expensive, messy technique.
I was not planning on doing this project until I saw a whitewash recipe shared on Facebook that used lime and Portland cement. Even better, it was the whitewash recipe A. Hays Town used in his homes. I couldn’t believe my luck!
Whitewashing brick has been popular in Baton Rouge since the 1960s when A. Hays Town utilized it in his iconic homes. It has also been popular around the world, especially England, for centuries for good reason!
I have to give a big thank you to Al Jones, a local architect who worked under Mr. Town, for providing his whitewashing recipe, answering my questions, and directing me to local suppliers. He gave me the insight I needed to develop my own original technique and recipe.
Whitewashing Supplies
How to Whitewash Brick with Lime & White Portland Cement
My brick whitewashing recipe and technique will allow some color to come through after one coat and will be opaque bright white after two coats. It can also be used on other porous surfaces such as stucco or cement.
IMPORTANT: You must use High Calcium Hydrated Lime.
All Hydrated Limes are not created equal and most big box/hardware store employees do not understand the very important differences. If it labeled for garden or agricultural use, it can not be used for whitewashing brick.
By definition, High Calcium Lime means that over 95% of the original limestone was Calcium Carbonate (CaCO3) with only up to 5% impurities.1
Hydrated Lime Type S can be used if that’s all you can find but the dry time and final color will depend on the magnesium content and every company’s formula differs.
For small projects like whitewashing brick fireplaces, pickling lime can be purchased in 1 lb bags.
For a deep dive into the different types of hydrated limes and available brands, read about them here.
- Make Lime Putty
Fill large 5 gallon bucket halfway with hydrated lime powder then slowly stir in clean, cool water until saturated. Keep filling with lime & water until nearly full, making sure to leave a few inches for water on top. Seal with lid.
Let sit at least 24 hours.
Though not required, making lime putty by adding water to hydrated lime powder the day before not only makes for a safer work environment but will also give you a smoother whitewash finish. Lime putty will last indefinitely as long as it is covered with water in a sealed container.
- Clean
Clean brick walls or fireplace surround well to remove dirt and dust with power washer, vacuum, or my favorite cleaner; Scott’s Oxi Outdoor Cleaner. Bricks need to be as clean as possible since the whitewash will adhere to the brick through carbonation. *science*
- Make Whitewash {start with small amount at first}
2 parts lime putty : 2 parts water : 1 part white portland cementDrain off water from lime putty so you can scoop out the thick, shortening-like lime putty from the bottom of the bucket. Whisk 2 cups lime putty with 2 cups cool water until smooth. Whisk in 1 cup white portland cement. I like using 16 oz wide mouth mason jars for the lime putty/water & a 8 oz mason jar for the portland cement to keep things consistent and organized.
If using Hydrated Lime Type S:
In medium sized bucket, whisk 1 cup white Portland cement: 1 cup hydrated lime together.(Video) How to Whitewash a Brick Fireplace - Add Water
Add enough cool water until it is the consistency of heavy cream.
Thin coats are better than thick coats as well as easier to apply. - Strain Mix
For the smoothest application, strain the whitewash mix with a fine mesh strainer. This will remove a surprisingly large clump of lime and cement bits that are much easier to remove after mixing with water.
- Spray down area
Wet area with a garden hose or garden pump sprayer until fully saturated to even out moisture levels between bricks and mortar in the wall/fireplace/etc.
Older bricks tend to suck up a lot of water and need to be sprayed down more often while newly laid bricks will stay moist longer.
- Mist small section
Starting at the top, mist a 3’x3′ section until moist but not sopping wet.
If your hand is wet after touching the brick, wait a few seconds for the excess water to evaporate.
- Stir then load brush
Using your large brush, stir the lime and cement whitewashing solution to resuspend particles and load the brush with whitewash.
Start off with a completely dry lime washing brush. A damp or wet brush gets very heavy and messy as soon as you load it. Having 2 brushes (one in use, one drying) on hand is best.
- Apply first coat
Cover every nook and cranny of mortar and brick with the lime whitewash. It should feel slick and a bit wild applying the whitewash in fast swipes of the brush.
(Video) How to: Lime wash Exterior Brick! Helpful tips to make completing this project easier!If your brush feels like it’s dragging or you are having to go over the same spot over and over, the brick may need to be remisted or your whitewash mix is too thick.
Avoid too much build up as it tends to crack as it dries.
- Mist, Paint, Repeat
Move onto the next section and apply whitewash in the same fashion by misting the bricks, letting them dry out a bit, slap on whitewash, repeat until the area is covered.
The lime and Portland cement whitewash will look transparent at first but turns more opaque and bright white as it dries.
- Let dry for at least 24 hours
Let dry completely before applying a second coat of whitewash.
This can take anywhere from overnight to a few days depending on the dew point, ambient temperature, wind speed, etc.
- Apply second coat
The second coat goes on exactly like the first one
Mist wall -> Slap on whitewash -> Move to next sectionA second coat is not required but it will completely cover the brick’s color and give you a brilliant white.
Heads up! See tips below if you don’t see this crackling.
When you mist the first coat of whitewash, it’s going to look like you royally messed it up. The whitewash will look like it has cracks everywhere. This just means it was applied & dried properly.
Whitewashing Brick Tips
– Lime whitewash is best applied when temps are between 60-80 degrees fahrenheit in shade.
– DO NOT FORCE DRY WITH FANS. Lime and Portland cement bind best when they dry slowly. Just remember, whitewash lasts forever so don’t rush it. If whitewash is drying too fast, (less than 24 hours) mist with water to allow adhesion. Repeat until you start to see fine cracks appearing when you first mist the whitewash. This means carbonation is happening and you are ready for the next coat.
– Starting at the top of the wall and working down in sections works best.
– The first coat is very slow and tedious process, especially if you have irregular brick like mine. It takes me 3 hours to whitewash a 10’x10′ brick wall. The second coat is much faster.
For more in-depth troubleshooting and info about whitewashing brick
Important Safety Information
- Hydrated lime is not the same as garden lime. You can find it with the cement or at your local Ace store.
- When working with hydrated lime, it is imperative you wear a dust mask, safety glasses, and gloves. Lime burns are no joke.
- No matter how careful you are, you will have splatter. Cover anything you want to keep clean.
- Clean up spills as soon as they happen. Once it dries, it’s not coming off. I’ve tried.
- Materials are cheap. Invest in a good lime washing brush. No, a masonry brush will not work. Trust me, I spent 8 hours cursing a bad brush.
Resources for research nerds like me
1. Carmeuse High Calcium (N) Normal Hydrated Lime
2. Durability of Traditional and Modified Limewashes (2007-18) by Sarah Jackson at NCPTT
3. Limewash: Compatible Coverings for Masonry and Stucco by Peter Mold & Richard Godbey
4. Documentation and Testing of Nineteenth-Century Limewash Recipes in the United States by Sloane Taliaferro