Limewash brick is brick finished with slaked lime thinned with water, a wash that soaks into the brick instead of coating it. The texture and some of the brick's own color stay visible, and over the years the surface weathers to a soft patina rather than peeling. At Paintzone, we offer limewash for exterior and interior brick, from a single fireplace to a whole house.
Whether it suits your house depends on the brick itself, on the weather window for the work and on how much patina you want as the years go by.
What is limewash brick, and how does the mineral finish actually work?
Limewash is a mineral finish made from slaked lime, also called hydrated lime or calcium hydroxide, mixed with water and brushed onto masonry. Instead of forming a film on top, it penetrates the pores of the brick. As it dries, it absorbs carbon dioxide from the air and hardens into calcite bonded to the brick, according to the Brick Industry Association (BIA).
That chemistry is what makes limewash a good fit for exterior walls. The BIA describes lime as fully compatible with brick masonry, and because it does not change how water vapor moves through brick, moisture inside the wall can still dry out through its face. This matters because, as the BIA notes, most brick deterioration comes from moisture that is not addressed, and a coating that traps water can make it worse.
The limewash we apply, Romabio Classico, is a slaked lime paint made in Italy that Romabio describes as permeable and breathable. Its technical data sheet sets which brick can take it, the weather it needs and how it wears.
How is limewash brick different from whitewash or painted brick?
Limewash and whitewash are easy to confuse, partly because, as the BIA notes, limewash was sometimes called whitewash in the past. Today, whitewash usually means light-colored paint thinned with water to imitate limewash, which the BIA calls a faux finish with very different performance.
The real difference is where each finish sits. Acrylic latex paint, thinned or not, forms a film on the face of the brick, while limewash soaks into the pores. That is why, outdoors, the BIA says semi-opaque paint should not be expected to last like limewash and is more likely to peel or flake. Over time, paint fails in patches, while limewash wears thinner.
Which brick can take limewash, and when does it need a primer first?
Limewash works best on brick that drinks it in, so unpainted, unsealed, absorbent brick takes Romabio Classico directly, according to its data sheet. To check your own brick, Romabio's application guide describes a quick water test. If water soaks into the brick, it will absorb limewash, and if it forms droplets or sits on the surface, it will not.
Other surfaces need at least one coat of Romabio MicroGrip Primer before the limewash, according to the same data sheet. MicroGrip is required on:
- Glazed brick
- Reclaimed brick
- Concrete brick or block
- Stucco, painted or not
- Painted or sealed surfaces
- Drywall
Because the primer is opaque and cannot be distressed, a primed wall takes an even, painted-looking limewash instead of letting brick show through. On reclaimed brick, Romabio adds that results are rarely uniform.
How much brick shows through, and how is a light limewash look made?
How much brick shows through is decided while the limewash goes on. Classico is thinned with water and applied as one generous coat, and as it starts to dry, it can be washed back with water to reveal more of the brick. The more it is washed back, the lighter the look, while leaving the coat alone gives fuller coverage.
Choosing the color takes a little patience, because Romabio notes that limewash dries much lighter and more opaque than it looks wet. That is why we judge the shade on a dry wall. Romabio's range runs from whites through beiges and grays, such as Avorio White and Cristallo Gray, and its tints are made with natural earth pigments.
When can exterior brick be limewashed in a wet climate like Seattle's?
Exterior limewash follows the weather, because Romabio allows Classico to go on only within set conditions. Air and surface temperatures have to stay between 50°F and 88°F, relative humidity under 80 percent, and the wall out of direct sun. Romabio also rules out exterior work when storms or showers are likely during the 12 to 24 hours the limewash takes to dry, and its guide says not to apply it if temperatures will drop below freezing within the next 36 to 48 hours.
Those limits matter in Seattle, where Sea-Tac averages 156 days a year with measurable precipitation, according to NOAA's 1991 to 2020 climate normals. For that reason, exterior limewash here is planned around a dry forecast, and walls with moss or algae are cleaned with Romabio's cleaner before the limewash goes on. For siding and trim, Paintzone also offers exterior painting in Seattle, where the best time of year to paint a Seattle exterior follows the same dry weather.
How long does limewash last on brick, and what upkeep does it need?
Limewash on brick lasts five to 10 years or more, according to the BIA, and where a wall falls in that range depends on how much weathering the owner wants. Outside, the BIA adds, limewash weathers gradually and often in streaks. Because the finish changes with each wall's exposure, Romabio does not offer a warranty on it.
Keeping limewash looking fresh takes little work. According to the BIA, a new coat can go over the earlier ones without removing them, and Romabio says touch-ups can be done at any time by wetting the area and applying more limewash.
For areas that stay wet, such as the bottom of a wall, sills and ledges, or spots near downspouts and sprinklers, Romabio offers Mineral Shield, a water repellent that still lets vapor pass. It is not a sealer, which matters because the BIA advises against sealing limewash where the wall needs to breathe.
Is limewash on brick permanent, or can it be removed later on?
Limewash can be removed only for a short time after it goes on, since Romabio says a high-pressure washer takes Classico off within two days of application. After that, the lime keeps curing for up to 20 to 25 days in ideal conditions and becomes part of the brick surface, so limewash is best treated as a long-term choice. The BIA also warns against using muriatic acid on limewashed brick.
Where does limewash work on interior brick, such as a fireplace?
Indoors, limewash suits decorative brick such as fireplace surrounds, accent walls and exposed chimneys, while the BIA advises against treating the inside of a working firebox. Since moisture removes limewash over time, interior limewashed brick is not typically washable, so it belongs away from splash zones. Beyond brick, Paintzone also offers limewash in Seattle for interior walls.
Limewash brick questions homeowners ask before choosing the finish
Is limewash on brick the same finish as a German smear mortar wash?
German smear is a different finish, a mortar wash that the BIA treats separately from limewash.
Is limewash safe to use indoors, on brick walls and fireplaces?
Romabio lists Classico at 3.9 grams of volatile organic compounds (VOCs) per liter, a very low level. Wet lime can irritate skin and damage eyes, though, so gloves and eye protection are needed while it goes on.
Sources
- Brick Industry Association, Technical Note 6, Changing the Appearance of Brick Masonry, August 2024
- Romabio, Classico Limewash technical data sheet, rev. 101624
- Romabio, Limewash application guide, 2021
- Romabio, Classico Limewash product page
- Romabio, limewash FAQ
- NOAA NCEI, U.S. Climate Normals 1991 to 2020, Seattle-Tacoma International Airport
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