Should you limewash your brick?

Limewash suits bare, unglazed face brick that soaks up water

Limewash works best on brick that drinks. Porter's says its Lime Wash performs best on bare, clean masonry with even porosity, and it lists unglazed bricks and bagged brickwork among the surfaces it suits. Glazed bricks and non-porous surfaces are on its list of places not to use it.

That's because limewash soaks in. Porter's describes it as non film forming and says it lets walls breathe and doesn't crack, peel or flake, provided the render has no hairline cracking or efflorescence.

It's also why limewash looks the way it does. Bauwerk Colour, an Australian limewash maker, says it lets some of the brick's character show through instead of a flat, even coat. You choose how much shows. A thin wash mutes a loud red or orange brick. A heavier one covers it almost fully.

Painted brick is a different job. Porter's says loose or flaking paint has to be scraped off first, then the wall gets its Limeproof Undercoat Sealer before the limewash. Bauwerk warns that a wall with paint in some spots and bare brick in others can come out lighter or darker in patches. For the wider picture on limewash across render, block and other walls, see our limewash paint guide.

Is limewash on brick permanent? No, it slowly wears away

No. Limewash on brick is a soft coat that wears away slowly. Porter's says its Lime Wash stays soft and gradually washes away over about 10 to 12 years, depending on the weather. In high rainfall areas or damp conditions, Porter's says the weathering speeds up.

That matters up here. The Bureau of Meteorology's Sunshine Coast Airport station averages 1,499 mm of rain a year, across about 107 days with 1 mm or more. Plan on topping it up rather than forgetting about it.

Topping up is the easy part. Bauwerk says upkeep is brushing off dust and putting on a fresh coat, with no need to strip the old limewash. Porter's says fresh coats can go over a sound, non-chalky surface. It also notes that each new coat shows more contrast in the bloom of the lime.

Going back to a normal painted finish is the harder part. Porter's steps for switching to acrylic are a low-pressure wash until the surface is stable and not dusty, or removing the limewash as well as cleaning allows. Then two coats of Limeproof Undercoat Sealer and a full 24 hours before the acrylic goes on. So treat limewash as a long-term choice, even though the coat itself isn't permanent.

Test your brick first with water and a hidden sample

Before you commit, test how your brick takes water and how the colour looks once it's dry. Bauwerk recommends testing first, and Porter's suggests a small test patch to check the limewash has stuck. It's the easiest way to avoid a wall you don't like.

1. Splash test. Bauwerk's site instruction is to brush or spray clean water on several spots across each wall. Even, moderate soaking is what you want. Very fast suction risks quick drying, lap marks and a patchy finish. Very low or uneven suction risks poor bonding and visible variation.
2. Sample off the wall. Bauwerk says to try your colour on a spare piece of the same brick or a hidden spot. Sampling right on the wall may leave a visible patch, because limewash soaks in.
3. Wait for it to dry. Bauwerk says wet limewash looks darker and see-through, then lightens and turns more solid as it dries. Judge the colour once the sample is fully dry.
4. Check it stuck. Porter's says a small test patch shows whether the limewash has bonded. On a low-suction surface such as acrylic render, its fix is two coats of Limeproof Undercoat Sealer first.

If one wall drinks fast and another barely takes water, Bauwerk says to split them into zones and adjust the prep for each. Bauwerk says to include repaired sections and mortar-rich areas in the test.

The downsides: salt, run-off marks, streaks and a soft surface

Limewash on brick has four main downsides, and the makers name them plainly. Each one is a reason to check the wall before you start.

Salt. White, powdery salt on brick is efflorescence. Porter's says it comes from water moving through the wall and leaving salts behind on the face. Its spec says the source of the water should be found and stopped, then the wall treated with its Salt Check before limewash. The Housing Industry Association says efflorescence must be removed before painting because it can stop coatings sticking.

Run-off marks. Bauwerk says weather, water run-off and salts can mark exterior limewash over time. Its fix starts with the building: check flashings, cappings, window junctions and sealants. Then rework the whole wall section. Bauwerk says spot fixes alone are likely to stay visible.

Streaks and colour shift. Porter's says the lime blooms as it cures, giving natural colour changes and often some streaking. That can show more around trims and window frames. If you want a perfectly even colour, limewash will frustrate you.

A soft surface. It can scuff. Porter's says it stays soft. Its care steps are a low-pressure wash with a mild detergent, and it advises against harsh brushes or stiff brooms, which it says can scuff or damage the soft lime surface.

Limewash, paint or whitewash: each one suits a different brick wall

Each finish suits a different owner, and none of them wins for every house. The word whitewash causes most of the mix-ups. Bauwerk says the term is now often used for watered-down normal paint, not true lime.

If you're still weighing paint against leaving the brick bare, our guide to painting a brick house covers that choice. For how long a painted coat holds up on the coast, read how long exterior paint lasts.

How limewash goes onto brick, step by step

Limewash goes on with a brush over damp brick, in two coats, then gets misted with water while it cures. Here's the order from Porter's Lime Wash specification, with Bauwerk's notes where they add something.

1. Let new brick cure. Porter's says bricks and mortar need at least 56 days before limewash.
2. Paint the trims first. Porter's says to finish all the trims and nearby surfaces before the limewash goes on.
3. Clean the wall. Porter's wants it free of loose material, dirt, grease, oil and mould. Sweep and hose it. If there's white salt on the brick, find and stop the water first, then treat it with Porter's Salt Check.
4. Pick your day. Porter's says don't apply in high humidity, below 10°C or above 30°C. Don't let the wall stay damp into an evening that drops below 14°C, or a whitish bloom can form. Bureau of Meteorology figures put 3pm humidity at Sunshine Coast Airport lowest in July and August, at 59%. January and February sit at 70% or more. But July and August nights average about 10°C, below Porter's 14°C limit, so finish early and let the wall dry before evening.
5. Dampen bare brick. Porter's says to mist unpainted masonry evenly first. If the brick sucks the water out of the limewash, it won't cure properly and can turn brittle and chalky.
6. Brush it on. Porter's uses a block brush in random, criss-cross strokes, worked into the brick texture. Keep a wet edge and finish at a corner or joint, or a dry edge mark can show.
7. Second coat. Porter's says ideally leave it overnight, and at least 8 hours, then dampen the first coat and apply the second the same way.
8. Mist to cure. Porter's says to let the final coat dry for 2 to 3 hours, then lightly mist it and let it dry, at least 6 times. If uncured limewash gets rained on, it can form a chalky white film or heavy white streaks.

For quantities, Porter's gives about 8 square metres per litre, depending on the brick. Bauwerk gives 7 to 10 square metres per litre per coat on raw brick, with two coats needed.

Stop the DIY at walls you can reach from the ground. Anything that needs a ladder or scaffold, such as a two-storey brick wall or gable ends, is a job for a professional.

Colour and finish: deeper colours move more, whites are easier to control

For a calm, even result on brick, pick a white or a soft neutral. Porter's says colour variation shows up more in deeper colours. So a dark limewash will show more colour variation than a pale one.

On brick, you also pick how solid the colour is. Bauwerk's own range shows the idea: a clear base for a sheer wash, a white it calls Whitewash for medium cover, and its Chalk white for full cover. Other makers name their colours differently, so sample before you choose. Then look at the dry sample in morning and afternoon light.

As for finish, Porter's describes the look as a soft weathered patina. Bauwerk says brick needs no sealer or top coat. If you do want one, it says to use a water-based sealer that dries completely flat, and to test it first because some sealers shift the colour. Bauwerk also notes a sealed wall needs another undercoat before it's redone, where an unsealed one just takes more limewash.

Think about the trims and roof too. Limewash shifts over time, so pick trim colours that sit well with both the fresh and the faded version. Our guide to choosing exterior house colours can help with the rest of the scheme.

Two-storey brick is a job for a licensed painter

Upper walls are where DIY limewash should stop. The Queensland Government says over 1,000 Queenslanders are hospitalised each year after falling off ladders, and most of those injuries happen around the home. If your brick goes above what you can reach from the ground, hand that part over.

Porter's own spec says to choose a painter who's highly skilled and knows the product's limits. In Queensland, the QBCC says anyone contracting for building work over $3,300 needs a QBCC licence. Ask for the licence number and check it.

We've painted Sunshine Coast homes since 1985, under QBCC licence 1281728. Our high-end project painters and exterior house painters work from Caloundra to Noosa, including our exterior house painters in Buderim. See every suburb on our locations page.

For a sense of what an exterior job involves, see exterior house painting cost. Then book a free site visit and we'll look at your brick before we quote.