Cleaning Aluminum Siding

To clean aluminum siding, choose a dry and windless day. The first thing to do is look for signs of mildew, curling and necessary repairs. Once you have determined what cleaning method to use, try to work as much as you can under the shade. Water pressure cleaning is a good technique for ordinary dirt and grit, while mold requires cleaning with a bleach or vinegar solution.

Choose the cleaning method

Look for loose or rotted pieces. Replace any that show signs of rot. Reclaim the those that are loose. Avoid pressure washing until you have made these arrangements.

  • Pressure washing loose or rotted pieces can cause water to seep through the lining and the back wall could absorb it.
  • If the aluminum cladding needs repairs and you do not feel capable of doing them, call a specialized professional.

Check for mold; Look for gray, green or black spots. Examine to determine if there are ruts. Look especially at the north side of the house and anywhere that does not receive much sunlight.

  • Eliminating mold requires more powerful cleaners. Even pressure washing will not stop the mold from coming out soon after.

Put on work gloves and rub the surface. Then look at the gloves to see if they have a light-colored powder.

  • Consider pressure washing if you find signs of chalk or embedded dirt.

Clean the lining with a brush and cleaning products

Get an extendable brush for coatings. Choose one that can range between 8 to 20 feet. As an alternative, you can attach a car cleaning brush to an extendable rod for paint rollers.

  • You can buy a specific extendable brush to clean linings or use a long pool brush.

Mix a cleaning solution in the bucket. Make sure that the brush head easily enters the bucket you choose.  Fill the bucket with hot water and a biodegradable detergent, guided by the product label. If necessary, add 3/4 cup of bleach or vinegar for every gallon of water.

  • Add bleach or vinegar if the coating shows any sign of mold.
  • Do not mix bleach with any product that contains ammonia.
  • You can use a specific cleaner for coatings, liquid dishwashers or a cleaner like Spic and Span.

Test the cleaner first in a small area. Wear gloves if the solution contains bleach or an aggressive cleanser. Moisten a clean white cloth in the solution, rub a small area of ​​the coating and see if it is powerful enough to do the job.

  • You can try different mixtures until you find the right power to clean the siding.
  • Adjust the mixture as needed, following all safety instructions for the product or cleaning products you choose.
  • Use eye protection if indicated by the product instructions.

Protect any plants near the cleaning area, if necessary. First, water the bushes, grass and other plant life near the house, and then cover them with tarps or plastic. Once you have finished cleaning, remove this cover and water the plants again.

  • Protect the grass and other plant life if you are using bleach or a chemical cleanser.

Moisten the siding with a spray bottle, if desired. Fill the bottle with the solution and moisten a portion of the liner about 20 feet wide for its total height. Let the solution settle a few minutes before brushing that area.

  • Pre-wetting the coating will reduce the subsequent rubbing time.

Brush the coating. Dip the brush in the bucket of the cleaning solution. Start at the bottom and go up.  Rub the lining to the sides, advancing and receding. Re-wet the brush when necessary.

  • The coating under the part you are cleaning must remain moist. Rinse it while you work so it does not dry out and come in contact with the dirty solution that is leaking from above.

Soak the siding with a hose. Put the hose in the jet position and soak the area you just brushed. Start at the top and go down.

Clean with water under pressure

Choose a pressure cleaner. Look for a cleaner that produces a pressure of at least 2,000 psi (pounds per square inch). You may have to pick it up with a van, minivan or pickup, and you need help loading and unloading it. Talk to the rental agent about how to connect and operate it and consult all the necessary security measures.

  • You can rent a pressure washer at home improvement stores.
  • If the cleaner does not come with nozzles, you will have to get them separately. You will need nozzles between 15 and 25 degrees.

Cover the area. Spread tarps, old sheets or plastic on the floor. Cover any nearby vegetation.

  • If the siding is sprayed, the covers will protect the floor from the paint flakes.

Protect yourself. Wear eye protection, sturdy shoes and long pants. Follow all safety precautions for the make and model of the pressure washer. Also, read the instructions for the methods of handling, blocking or shutting down.

  • It is vital that you protect yourself properly. The jet of a pressure washer is very powerful and dangerous. Its force can cause many types of serious injuries.
  • If your house was built before 1977, or if you do not know for sure if the paint on your siding has lead, give it an analysis. You can ask the local health department to provide you with safety instructions.

Coupling the 15-degree nozzle. Do not use settings below 15 degrees, and above all do not use a zero-degree nozzle with a pressure cleaner.  Make sure you fix it properly.

  • If the nozzle is not properly fixed, it may pop off when you turn on the cleaner.

Turn on the pressure washer. Attach the washer to a normal garden hose and attach it to an outside water supply. Start the engine.

Practice using the cleaner from a couple of steps away. Go closer until you find the most appropriate point. Apply the water horizontally or at a slightly downward angle.

  • Use the cleaner with caution, as it may leave marks on the coating or take off finishes.

Rub the coating or raise the pressure, if necessary. If a low-pressure wash does not work, rub the coating with a soap solution and continue with a low-pressure rinse. Alternatively, you can do a test wash with a 25-degree nozzle in a not very visible area. Make sure that no damage occurs before proceeding with the cleaning.

  • Continue with a high-pressure wash, knowing the risk that you can damage the test area.


  • Trisodium phosphate (TSP) is no longer recommended for tasks such as washing siding, due to its extreme power and the risks it poses to people, animals and the environment.
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