Brick hides nothing. Fireplace soot, green moss on the shady side of the house, and chalky white salt all sit right on the face, and the pores that give brick its warmth are the same pores that hold dirt in place.
Most brick still comes clean with water, a soft brush, and a mild solution already under your sink. What separates a good clean from a damaged wall is matching the method to the mess and keeping the pressure low enough to spare the mortar.
Here is how to clean brick inside and out, which cleaner suits each stain, and how to clear mold, moss, and mildew without chewing up the joints.
Key Takeaways
- Prep the surface: Vacuum interior brick with a soft brush attachment to lift loose soot and dust before any liquid touches it.
- Saturate first: Wet the brick with plain water before any cleaner, so the porous face holds the solution on top instead of drinking it in.
- Use the right tools: Scrub with a nylon or natural bristle brush; metal bristles abrade the brick and leave particles that rust and stain.
- Exterior maintenance: Keep a pressure washer at 500 to 1000 PSI on sound modern brick, and treat old or historic masonry far gentler, closer to a garden hose.
How Often Should You Clean Brick?
Wash exterior brick once a year, clean a fireplace surround at the end of every burning season, and dust interior brick monthly. Brick is low maintenance rather than no maintenance, and the schedule follows whatever lands on it.
- Exterior Brick: Wash the facade once a year to clear road film and dirt before moss gets a foothold. Shaded north-facing walls stay damp longest and usually need it first.
- Fireplaces: Clean the brick surround after every few fires, or at the close of the burning season. Soot that sits through a summer bonds to the surface and stops rinsing off.
- Interior Walls: Dust exposed brick monthly with a vacuum brush. Do a wet clean once or twice a year, or the moment a stain appears, while it is still on the surface.
What Is the Best Cleaner for Brick?
The best cleaner for brick is the mildest one that clears the stain: white vinegar for efflorescence, dish soap and salt for soot, diluted bleach for mold, and TSP for grease. Harsh industrial chemicals degrade old mortar, so save strong acids like muriatic acid for a true last resort (see the FAQ below). Here are the options worth keeping on hand:
- Vinegar: Mix equal parts distilled white vinegar and water. This is excellent for removing efflorescence (white salt deposits) and general cleaning on newer brick.
- Dish Soap and Salt: Create a gritty paste using equal parts dish soap and table salt. The salt gives the paste enough bite to work soot out of the pores without a stiff brush.
- Cream of Tartar: Mix two tablespoons of cream of tartar with a small amount of water to form a paste. Apply this directly to small, stubborn stains and let it dry before brushing it off.
- Boric Acid: Dissolve one tablespoon of boric acid in a gallon of warm water. This is a good antifungal option for outdoor areas where you would rather not use bleach near plants.
- Bleach: Use this for mold and mildew removal on exterior brick, diluted with water (see the dilution below).
- Trisodium Phosphate (TSP): This is a heavy-duty cleaner for tough grease or smoke stains. Mix ⅛ cup of TSP per gallon of hot water.
- Pressure Washer Cleaners: For large exterior jobs, use a specialized masonry detergent in your pressure washer to break down road film and grime.
Safety First
Strong cleaners like TSP and bleach require caution. Always wear rubber gloves, safety goggles, and a face mask, and never combine two products in the same bucket. Ensure the area is well-ventilated.
How Do You Clean Interior Brick?
Vacuum the brick, wet it with plain water, scrub with a vinegar solution or a soap and salt paste, then rinse with a clean sponge. Interior brick, like a fireplace surround or an accent wall, mostly collects soot and dust, so the gentlest routine is usually the one that works.
- Time: 20 to 30 minutes.
- Difficulty: Easy.
Supplies Needed
- Vacuum with brush attachment.
- Spray bottle filled with water.
- Cleaning solution (Vinegar/water or soap paste).
- Nylon-bristled scrub brush.
- Drop cloths or old towels.
- Bucket of warm water.
1. Protect and Prep
Lay down drop cloths to protect your flooring from runoff. Use your vacuum’s soft brush attachment to pull loose dust, cobwebs, and soot off the brick face and out of the mortar joints, since anything you leave behind turns to grit the moment it gets wet.
2. Mix Your Solution
Prepare your chosen cleaner. For general cleaning, a 50/50 mix of vinegar and water in a spray bottle is easiest. For heavy soot, mix dish soap and salt into a thick paste that clings to a vertical surface instead of running down it.
3. Wet the Brick
Spray the brick with plain water first. Dry brick is thirsty enough to swallow a cleaner on contact, which strands the chemical inside the pores where the dirt is not. Pre-wetting keeps the solution on the face, working on the stain.
4. Scrub the Surface
Apply your cleaning solution. Work in small sections, starting from the top and moving down. Use your nylon brush to scrub in a circular motion, and rewet a section if the cleaner starts to dry.
- Note: Avoid wire brushes. Metal bristles scratch the brick face and leave behind fragments that rust into orange streaks weeks later.
5. Rinse and Dry
Dip a clean sponge into a bucket of warm water and rinse the brick thoroughly, changing the water as soon as it turns grey. Leftover soap film attracts dust, so rinse further than you think you need to, then blot with a dry towel and let the wall air dry.
How Do You Clean Exterior Brick Without Damaging the Mortar?
Let the detergent do the work and keep the water pressure low. Cleaning a whole facade takes more reach, not more force, and most of the damage people blame on brick cleaning traces back to pressure, dwell time, or a joint that was already failing.
The method that fits is soft washing: a low-pressure stream through a wide 40-degree nozzle, paired with a biodegradable masonry cleaner that breaks grime down chemically instead of blasting it off. On sound modern brick, that means staying in the 500 to 1000 PSI range. According to the National Park Service, cleaning historic masonry should begin at 100 psi or below and rarely needs to go past 300 to 400 psi (1), so treat anything old, soft, or hand-made as a garden hose job until it proves otherwise.
Check the joints before you wash anything. Per the pressure washing guidance from Ferguson, patch cracked or crumbling mortar and let the repair harden for about 7 days before water hits the wall (2). Spraying an open joint drives water behind the brick, where it has nowhere to dry and feeds mold inside the wall.
Warning
Never exceed 1000 PSI on brick, and drop to a garden hose or the lowest setting on old or historic masonry. Too much pressure blasts away mortar and chips the brick face. Keep the wand moving, since holding it in one spot is what causes damage.
- Time: 1 to 2 hours.
- Difficulty: Intermediate.
Supplies Needed
- Garden hose or pressure washer (low PSI).
- Masonry detergent.
- Stiff broom or brush.
- Tarp and plastic sheeting.
- Protective gear.
1. Prepare the Area
Cover nearby landscaping with tarps. If you are using bleach or chemicals, soak the soil and plants with plain water first, since a saturated root zone takes up far less of the runoff. Cover electrical outlets and windows with plastic sheeting.
2. Apply Detergent
If using a pressure washer, fill the tank with a brick-safe detergent like Sun Joe All-Purpose Cleaner. Apply the soap from the bottom up using a low-pressure nozzle, which stops clean streaks from running through dirty brick below. Let it sit for 5 to 10 minutes to break down the dirt, but do not let it dry.
3. Scrub (If Needed)
For heavily soiled areas, use a stiff broom or brush to agitate the dirt while the detergent is still wet. Agitation clears far more than turning the pressure up, and it costs the mortar nothing.
4. Rinse Top to Bottom
Switch to a rinse nozzle or use your garden hose. Rinse from the top down so the dirty water runs off sections you have already cleaned. Keep the pressure low, around 500 to 1000 PSI on modern brick and lower on old walls, and keep the nozzle at least 12 inches away from the surface.
How Do You Remove Mold and Mildew From Brick?
Wet the brick, apply a diluted bleach solution, let it dwell a few minutes, then scrub and rinse. Shaded brick grows green moss and black mold because it stays damp, and bleach is the most effective remedy for that kind of organic staining.
- Time: 15 minutes per section.
- Difficulty: Easy.
Supplies Needed
- Bleach.
- Bucket and sponge.
- Garden hose.
- Protective gloves and eyewear.
1. Safety Check
Ensure the area is clear of pets and children. Wear old clothes and protective gear, as bleach can damage skin and fabrics, and work on a still day so the spray does not drift onto a neighbor’s plants.
2. Pre-Wet the Wall
Spray the moldy area with water. As with interior cleaning, this stops the bleach from soaking deep into the porous masonry, where it does nothing for the surface stain and takes far longer to rinse out.
3. Apply Bleach Solution
The CDC caps a household mold-cleanup mix at 1 cup of bleach per 1 gallon of water (3), and that strength is plenty for brick. Apply it with a sponge or a pump sprayer and let it sit for roughly 5 minutes so it can kill the spores and lift the stain.
4. Scrub and Rinse
Scrub the area with a stiff brush, then rinse thoroughly with a garden hose. Wash off every trace of bleach, including the wall below the section you treated, or the residue dries into pale streaks.
Essential Brick Cleaning Tips
These are the habits that separate a clean wall from a repointing bill:
- Spot test first: Per the National Park Service, try a test patch of about 36 inches by 36 inches in a low-visibility spot before you commit to a whole wall. A patch that size shows how both the brick and the mortar react, which a coin-sized dab cannot.
- Pre-soak is mandatory: Never apply cleaner to dry brick. The water barrier keeps the dirt on the surface where it is easier to remove.
- Check the weather: Avoid cleaning exterior brick on hot, sunny days. The cleaner dries too fast and leaves streaks. Overcast days above freezing are best.
- Gentle pressure: If you use a pressure washer, start with the lowest setting. You can always increase pressure slightly, but you cannot undo damage to mortar joints.
- Use the right brush: Soft nylon or natural bristles are best. Commercial masonry sponges are also excellent for trapping soot without abrasion.
How Can You Restore the Look of Old Brick?
Repointing, limewash, and a German smear each refresh tired brick without replacing a single unit. Cleaning does most of the work, but sometimes the masonry needs more help than soap can give.
Here are the options, roughly in order of how much they change the look:
- Repointing: If the mortar is crumbling or cracked, repointing (raking out the old joints and packing in fresh mortar) stabilizes the wall and sharpens every line on the facade.
- Painting or Whitewashing: For a dramatic change, consider painting the brick or applying a whitewash (limewash). Limewash lets the texture show through and wears back gradually, while paint seals the face and has to be maintained.
- German Smear: This technique involves smearing wet mortar over the brick face, creating a rustic, old-world cottage look. Coverage is deliberately uneven, so it hides mismatched repairs well.
- Landscaping: Sometimes the brick looks fine and the surroundings are dull. Trimming overgrown bushes also cuts the shade and trapped moisture that grew the moss in the first place.
FAQs
Beautiful Brick
Clean brick comes down to two habits: wet the surface before any cleaner touches it, and match the cleaner to the mess. Water and a soft nylon brush handle most dirt, so save vinegar for efflorescence, bleach for mold and moss, and TSP for grease or heavy soot.
On exterior work, keep the pressure low, gentler still on old mortar, and let the detergent lift the grime instead of the spray. Do that and you clear years of buildup without opening a single joint.
