If you’re considering washing your own house siding, you should know that using the right house cleaners can be a huge time saver and give you better results. Most of the stains you’ll be dealing with will be mold, mildew, algae, dirt, cobwebs, bird droppings, and bug poop.
The Vinyl Siding Institute (VSI) recommends using the following house siding cleaning solution for small spots of mold or mildew. Small spots of mold and mildew can be handled with cleaners such as Fantastik® or Windex®. For larger sections, a solution of vinegar (30%) and water (70%) has proven successful. You could also try the following solution: 1/3 cup (2 2/3 ounces) powdered laundry detergent (e.g., Tide®, Fab®, or equivalent), 2/3 cup (5 1/3 ounces) powdered household cleaner (e.g., Spic & Span®, Soilax®, or equivalent), 1 quart (32 fluid ounces) liquid laundry bleach, and 1 gallon (128 fluid ounces) of water.
In my experience, the only way to kill and fully remove mold and mildew is to use the bleach solution. It’s not only important to remove mold and mildew – but to kill it as well. Cleaning mold or mildew with just water or a soap solution may look good at first but it grows back in a short time because it wasn’t completely killed.
Also know that bleach is for removing mold, mildew, and algae but does not clean well. For regular dirt and grime you will also need soap in your vinyl siding cleaner. You can use the laundry soap like recommended by the VSI or add a few squirts of dish soap to your bleach mix.
The house washing solution mentioned above can be applied with a brush or sponge. You can try using a pump up sprayer but bleach is corrosive and will eventually ruin the sprayer. It may work long enough to get the job done or perhaps longer if you rinse it with fresh water every time you’re finished using it.
If you’re going to use your pressure washer’s chemical injector to apply the cleaner, it’s important to note that it will be diluting your house cleaning mix. Most injectors draw only 1 part chemical to 5 or 6 parts water. You can figure the math and attempt making your initial cleaning solution stronger to see if you can get good results.
Once you’ve found a good solution that is strong enough, it should do most of the work for you. After applying the solution, allow it to dwell for a few minutes before using your garden hose or pressure washer (with 1000psi or less and a wide fan nozzle) to clean the area. Try to spray level with the siding or you can force water underneath the siding.
It’s important to rinse from top to bottom and to be thorough not leave any soap residue on your home. You can add some dishwasher rinse aid like Jet Dry to your mix so the water sheets off better and reduces spotting on your windows. An 8 oz bottle will treat 5 gallons of exterior house cleaning solution.
The bleach, water, soap, and rinse aid (optional) cleaning solution will also work well on aluminum and painted wood siding. It can also be used for vinyl fences, plastic or composite decking, painted shutters, lawn furniture and most anything around the home that is exposed to the elements.
Make sure when working around your plants and shrubs that you wet them down with water before, during, and after the cleaning process so no solution is allowed to dry on them. The same goes for your windows, don’t allow the solution to dry on them and you’ll avoid any problems. Also remember to wear personal protection like safety glasses and gloves when dealing with bleach. Never mix ammonia with bleach or anything else you aren’t sure of.