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How To Use A Pressure Washer To Remove Mold And Mildew

Mold and mildew can be a nuisance to homeowners. Not only are they unsightly on walls and driveways, they can be harmful to the health and lifestyles of the people around. If you’re having issues with mold and mildew growing around your house, there are several ways you can address this problem. I’ve found one solution in particular to be fast, cheap and effective.  Let me share it with you.

A pressure washer can effectively remove mold and mildew growing around your house.  Use it on your building walls, fences, decks, sheds, walkways and driveways. Whatever surface you have mold and mildew growing on the outside, whether it be wood, vinyl, brick or concrete, a pressure washer when used properly should be able to take it all away.

Steps For Pressure Washing Mold And Mildew

Step 1:

Wet down the surrounding plants and saturate the soil.  This will help prevent the plants from absorbing the chemicals from cleaning detergent.

Step 2:

Start by washing the affected surface with detergent.  Don’t just use any all-purpose cleaning solution. These products won’t work as well and mold and mildew will return not too long after treatment.  

Purchase a mold and mildew concentrate for your pressure washer.  Mix the concentrate solution with appropriate amount of water to properly dilute solution.  Then pour it into your pressure washer detergent tank.

Step 3:

Next select a black-colored nozzle. This is a low pressure detergent nozzle that is safe to use on cleaning projects.  Sometimes this detergent nozzle is pink. Never use a red-colored nozzle. Put the nozzle on your pressure washer.

Step 4:

Start spraying the surface, starting from the bottom and working towards the top, moving horizontally with back and forth strokes.  Doing it this way helps prevent streaking that would otherwise occur if you work from top to bottom.

Also, stand about a foot away from the surface initially, and adjust your distance as appropriate.  Be careful of possible recoil from the pressure washer. Hold the wand with both hands for better support.  Work your spray in small sections.

Step 5:

Use a pressure washer extension wand if you’re washing a two-story house siding. It is not recommended that you pressure wash on a ladder, as it is easy to lose balance and fall from the force projected from the washer.  Invest in an extension wand. It’ll come in handy for those hard to reach high places.

Step 6:

Let cleaning detergent soak and sit on the surface for 5 to 10 minutes.  Don’t let the surfaces dry out completely.

Step 7:

Switch to a white-colored nozzle, which provides for a wider fan of water and a little bit more water pressure than what the black-colored nozzle gave.  

You’ll want to be careful about the nozzle you select when rinsing.  Some surfaces, like brick, are softer than others, so it’s a good idea to test out on a small patch before jumping up a color-coded nozzle tip for more water pressure.  

If your surface can handle a white nozzle spray without any problems, try choosing a yellow-colored nozzle.  Yellow nozzles are good choices for removing dirt, mildew and paint.

Step 8:

Start rinsing the surface from top to bottom.  Work in small sections with horizontal strokes like what you did when washing with detergent.

Now of course that sounds a lot easier said than done.  But it isn’t just spray and kill. If only job were only that simple!  There are some considerations you should be mindful of before starting a project like what we’re talking about.  You’ll need to know what kind of pressure washer to use, be aware of the surface you’ll be working on, take heed with the amount of pressure the washer will be putting out, and be safe with the cleaning agent you’ll be using.  I’ll elaborate on these points and more right now.

Use A Hot Water Pressure Washer

Besides the common choice between either gas or electric pressure washers, did you know that there are washers that use hot water and washers that use cold water?  Which one should you use for the specific task of removing mold and mildew? Both will actually do the trick, but a hot water pressure washer will do the job better.  Let me explain.

Mold and mildew are part of the fungi family.  You know… like in mushrooms and all? They are living organisms and their spores can be in the air and can stick to surfaces in settings where it’s warm and shaded or dark.  Breathing in these spores can cause health complications, especially for those that suffer from asthma and allergies.

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Now you know what living organisms hate?  When things get too hot. Hot water does a much better job of killing these spores, and when you combine that with a powerful water blast you’ll be able to remove the mold and mildew off whatever surface in no time.  Using hot water to pressure wash is often called power washing. These terms are interchangeable.

But that’s not to say you can’t do the same with a cold water pressure water.  There are antimicrobial cleaning solutions that you can add to pressure washers for a deeper clean.  More on that later.

Consider Using Bleach or Vinegar Before Pressure Washing

Some prep work before you start pressure washing can enhance the cleanliness of your targeted surface.  Bleach and vinegar are well-known disinfectants that kill bacteria, fungi and viruses. You can use mixed solutions of either to remove mold and mildew and their spores.  

Dilute with water to the appropriate concentration, pour into a spray bottle or a hand pump.  You can use the same hand pump that you use for weed killer solutions. Then apply to the surface.

With bleach you’ll want to create a solution that has 1 part bleach and 3 parts water.  If you’re using vinegar try a solution that has 1 part vinegar and 1 part water.

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After applying the bleach or vinegar solution, let it sit for 5-10 minutes before continuing on to pressure washing for the dirty work of washing and rinsing.  The pressure washer will do a better job of tackling the removal of accumulated dirt and grime.

Be sure not to fill your pressure washer with either of these solutions.  They will damage your pressure washer. Bleach is very corrosive on metals and pipings.  Do the prep work by hand first, then wash and rinse with the pressure washer.

Choose Pressure Washer With PSI Range 1000 to 2000

PSI is short for pounds per square inch.  Why is this metric important? Because basically PSI translates to the force with which the pressure washer sprays out.  The higher the PSI the greater the force of water will be that comes out. With more force coming from the water you can get a deeper and more thorough cleaning.  However, this comes with the risk of damaging the surface you are washing.

You’ll want to work with a pressure washer that puts out an adequate amount of PSI without damaging the surface where mold and mildew are on.  Always test out the water pressure that’s expelled on a small and discrete part of the surface you’re washing so you can be sure no damages will incur.

  • 1000 to 2000 PSI is a good range for patio furniture, siding, sidewalks and vehicles
  • 2000 to 2800 PSI is a good range for siding, fences, decks and patios.
  • 2900 to 3300 PSI is a good range for paint stripping, large areas, second story houses.

Most electric pressure washers run up to 2000 PSI, which is suffice for most common pressure washing surfaces around the house.  Gas pressure washers are more powerful than electric ones. With that power you’ll need to be careful about not stripping away paint or damaging surfaces.

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Final Thoughts

Pressure washing is a great way to remove mold and mildew outside your home.  It’s fast, effective and easy to do. No more labor-intensive scrubbing with bleach and soap.  These cleaning projects can take all day! With a pressure washer you just point the wand to the areas you want to clean and pull the trigger.  It’s fun and exhilarating watching mold and mildew being blasted off! Enjoy your clean house exteriors in no time and have peace of mind that the mold, mildew and their spores are gone and won’t be giving you any health concerns.