How to Clean Bricks

You’ll need to repair any cracks in your bricks or mortar before using a pressure washer on the required surface. Make sure to cover and protect light fixtures, electrical outlets and jacks with a waterproof material as you don’t want water to penetrate and harm them. Also, be sure to cover nearby shrubs, bushes and flower beds and ensure that your windows are closed so no water gets into your home. You may want to have a professional opinion before pressure washing brick that is older, as they may not stand up to the pressure from the washer.    

Using a detergent can loosen up debris and discolouration, making it easier to remove spots and stains. Use a low-pressure nozzle on the pressure washer and spray the detergent on the affected area. Let it sit for a few minutes and really soak in. Check the package for instructions as to how long to leave it on for before starting the pressure wash.    

Using a surface cleaner attachment or high-pressure nozzle, clean your bricks from top down, allowing the dirt and debris to flow down the wall or along the path in one direction as you go. Try to spray in horizontal strokes over a 3- or 4-foot-wide area at a time. The manufacturer's instructions will give you the ideal nozzle distance you should keep from the cleaning surface. You can increase the PSI (pressure) as needed and when done, be sure to rinse the walls or path thoroughly with a regular garden hose.    

Once the job is complete, wait 24-48 hours and  spot-treat any leftover stains that your pressure washer left behind – things like mildew or masonry bloom. Use water and cleaner with the sprayer to attack those stains and clean them up. For stubborn stains, use cleaner and scrub with a wire brush. If you’re dealing with mildew and mold, use equal parts chlorine bleach and water to make short work of them. Dilute an acid-based masonry detergent to tackle rust, following the manufacturer's instructions carefully. Rinse thoroughly and let dry.