Q&A / 

How to Clean Exterior Siding

Cleaning Exterior Siding

The mildew and algae on this vinyl siding can be removed quickly with a solution of oxygen bleach. (C) Copyright 2017 Tim Carter

How To Clean Exterior Siding TIPS

DEAR TIM: My primary home and a camp I own in the woods both are covered with siding. One is wood, the other is vinyl siding, and both are dirty.

In the past few years, I've been stunned to discover mildew and algae growing on the vinyl siding. I thought vinyl siding was supposed to be maintenance-free, that's why I purchased it.

What's going on? Should I just drag out my pressure washer and get to work, or is there an alternative method to clean siding on houses? Patrick O., Fryeburg, ME

DEAR PATRICK: Each week I receive emails from homeowners just like you. They share your astonishment about having to clean their vinyl siding. Many homeowners are not too happy as the salesmen's claims about no-maintenance seem to be as hollow as an old log.

IMPORTANT TIP: Maintenance-free is a myth. All exterior surfaces must be cleaned on a regular basis. They include:

  • siding
  • decks
  • windows
  • docks
  • roofs

CLICK HERE to get FREE & FAST BIDS from local handymen who can easily clean your siding.

I've seen hundreds of printed ads, heard countless radio commercials, etc. with these maintenance-free statements when it comes to exterior home improvement products.

Decking, siding, railings, fencing, etc. are often touted as requiring no future care. As you now know, it's just not true. Certain products are absolutely reduced-maintenance, but not maintenance-free.

Algae & Mildew Food

You're probably wondering how mildew and algae can survive on plastic, or vinyl siding. The mildew and algae are feeding on sugars, dust, dirt, or other things that are attached to the siding.

Many people are unaware that trees, both evergreen and deciduous, often broadcast ultra-fine aerosols of sugars at different times of years. Park your car under certain trees, and you'll discover thousands of tiny droplets of sap or sugar on the painted finish and glass.

This is yummy food for mildew and algae!

Wood Stain Food

When it comes to wood siding, the mildew and algae are possibly feasting on the actual stains and sealers you may have used to preserve the wood. Many clear and semi-transparent wood sealers and stains are made with alkyd or oil resins.

These natural oils are also delicious food for mildew and algae. Some of the sealers and stains contain chemicals that are designed to prevent mildew and algae growth, but these chemicals do breakdown when exposed to sunlight and repeated exposure to rainwater.

Spiderman® Power

I know that you may love your pressure washer because it's a cool tool, but it can wreak havoc with houses if used improperly. Pressure washers are like Spiderman® - "With great power comes great responsibility."

The water that's ejected from the tip of the pressure washer wand can be driven into cracks and crevices where water is not supposed to go. The intense water stream can and will erode the lighter-colored spring wood in your wood siding causing it to look older than it actually is.

Water Behind Siding

Water driven behind vinyl siding at lap joints and corners can cause wood rot if your house lacks a proper weather barrier under the vinyl siding. Believe it or not, this requirement was lacking from the building code for many years.

There are tens of thousands of houses, maybe hundreds of thousands, that do not have a weather barrier under the siding. The siding is nailed directly to wood sheathing.

CLICK HERE to get FREE & FAST BIDS from local handymen who can easily clean your siding.

Stain Solver

Oxygen Bleach

Stain Solver is MADE in the USA with USA ingredients that are food-grade quality. CLICK THE IMAGE to order some NOW.

Perhaps the better way to clean the mildew and algae off your house is to use a hand-pump garden sprayer, some Stain Solver certified organic oxygen bleach and a brush on a pole. I just demonstrated this method last week to a homeowner, and he was amazed at how well it worked.

Don't confuse oxygen bleach with chlorine bleach. Chlorine bleach can remove the color from wood siding, and it can kill expensive landscaping around your home.

Stain Solver oxygen bleach will not remove color from wood, and it's safe to use around plants and animals.

Easy DIY Use

To clean your wood and vinyl siding, you just mix the powdered Stain Solver with warm water, stir till dissolved and then apply it generously to the siding.

It's best to work when the siding is in the shade. Allow the solution to fizz and bubble on the siding for about ten or fifteen minutes. Scrub with the brush and rinse with clear water from a garden hose. The siding should look brand new once dry.

RV Brush Best

Use the type of brush on a pole RV owners use to clean their expensive vehicles. An RV brush will not scratch automotive paint, so you know it's perfect for your vinyl siding.

rv brush

This is a perfect brush to clean vinyl siding. It's got an adjustable handle and the perfect bristles that remove dirt loosened by using Stain Solver oxygen bleach. CLICK THE IMAGE NOW TO HAVE THIS BRUSH DELIVERED TO YOUR HOME.

Apply Dry

It's always best to apply the oxygen bleach solution to dry siding. This allows the solution to soak into the wood and deep clean it. Oxygen bleach can and will remove sun-damaged wood sealers and stains from the wood. It can absolutely remove sun-damaged and oxidized paint pigments from painted surfaces.

This makes it an excellent product to use if you're getting ready to re-stain or repaint your home. You want to remove these damaged finishes before you apply new.

Clean Twice a Year

For periodic cleaning to prevent mildew and algae buildup, just wash your home twice each year with a solution of liquid dish soap, a small amount of Stain Solver and water. Remove the sugars from the siding before the mildew and algae sit down at the table to feast!

CLICK HERE to get FREE & FAST BIDS from local handymen who can easily clean your siding.

Column 987


23 Responses to How to Clean Exterior Siding

  1. I have aluminum siding that faded and I primed and painted and we have had so much rain in Oklahoma City this year that all the way around the house you can see black specs and of course worse on north side I am wondering will this product you sell I suppose oxygen bleach solution will it work and not damage the paint that I put on there also do you have to use a scrub brush as it is not real heavy or can I use a power washer that is turned down on pressure so it won't knock the paint off?

  2. I had Whole Foods brand Oxygen Bleach. The ingredients are Sodium Carbonate peroxide and Sodium Carbonate.I followed the directions on the container for stains.; 2 cups of warm water per 1/2 Tablespoon. I applied it with a car wash brush on a pole. It did not fizz up. It did take off some so the mold and mildew but not all of it. Is my solution too weak or is the product missing something?

    • Billye,

      You used the wrong brand. You need my Stain Solver. What's more, there's a good chance the brand you used is not Certified organic and it may have impure offshore ingredients. Stain Solver is Certified organic and all ingredients are Made in the USA. CLICK HERE to get Stain Solver.

  3. I have white vinyl and live on a dirt road,front of house and below windows are stained where rain does not wash it off,tried zepp products with power washer and scrubrush,it helps some but still looks bad,any ideas ?

    • Chlorine bleach - sodium hypochlorite - is VERY TOXIC to all vegetation. It's the LAST PRODUCT to use if you want to preserve your grass, landscaping and valuable trees in and around your home.

      My neighbor systematically MURDERED two gorgeous maple trees next to her patio by cleaning the patio under the trees with chlorine bleach. I warned her for years to STOP, but she thought I was just a dumb ass. She paid arborists thousands of dollars to try to save the sick tree. Then, after ten years, she paid thousands more to have them cut down and taken away.

      The BEST product to use is certified organic Oxygen Bleach.

  4. Tim,
    Cleaning up the exterior of our yacht club in Pentwater, MI this spring.
    Plastic siding needs to be cleaned and brightened up. I will have volunteers to help do this project.
    Ladders to get to the peeks with soft brushes and Stain Solver is the plan. Any other suggestions to make this a successful project?

    • Russell,

      You bet. Here's the Success Checklist:

      Use warm / hot water to mix.
      One cup SS powder per gallon of water
      STIR until completely dissolved.
      Use hand-pump garden sprayer to apply solution
      Saturate DRY siding working in the shade
      Keep siding WET with solution for at least 15 minutes not allowing to evaporate
      Scrub siding with RV brush adding some liquid dish Dawn soap
      Rinse with lake or hose water.
      Celebrate your AWESOME CLEAN siding!

  5. I didn't realize that algae or mildew could survive on vinyl siding due to droplets of sap. I can see how cleaning your house regularly could prevent unsightly and possibly harmful mildew though. If the situation is getting out of hand, it might make more sense to just replace the siding entirely.

  6. Yeah, that's funny. I had a wood fence that always seemed to need painting. So I thought I'd replace it with the maintenance free vinyl fence. You guessed it, I had to clean it every year after that. I solved that problem permanently by moving to a dryer climate without a fence. 🙂

  7. I have a Image II standing seam metal roof. Will any of your recommended vinyl cleaning products/solutions harm the coloring of the metal roof or metal itself?

    • All steel metal roofs that are painted will SUFFER eventually from UV light degradation. The paint resin and pigment will FAIL and break off.

      My Stain Solver is designed to CLEAN off this destroyed material. So the cleaning product is not to blame, it's the active photons in the UV light causing the problem.


  8. I didn't realize either that siding is susceptible to things like mold growth. I recently noticed some growing on a higher portion of my home's siding that I don't feel comfortable reaching myself. I guess my best bet going forward would to hire a handyman that can come clean it for me.

  9. I have a recurring mold/mildew issue on the siding on the north side of my house. It gets zero sunlight so I pressure wash every year and it returns. Was wondering if I could provide artificial sunlight to that side of my house to prevent it from coming back. Would installing exterior lighting set to shine on that side of my house replace the benefits of the sun in preventing mold/mildew growth? If so, is there a special type of bulb (UV, IR)?

    • Bill,

      The column above has your answer. All you have to do is get the food source off the siding.

      Use my Stain Solver to do it FAST and EASY.

      Once the siding is clean, you can spray it with a copper sulfate solution to help prevent the mold, but the BEST WAY is to just periodically clean it as soon as you see the mildew return.

  10. Hello Tim. I'm curious how much Stain Solver I'll need to clean the exterior vinyl siding on my 2600 sq. ft. colonial once. One side faces due North, so it's by far the worst and will need more product than the others. My East side has shade trees so it needs more attention than the South and West sides which get full sun without any relief until sundown (and are virtually mold and mildew free, but I'll still clean/wash them). I'd like to purchase at least enough SS for the two annual cleanings - to keep me motivated to do it both times and not have an excuse because I'm out of the special sauce! Thanks! Kevin.

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