Middletown, NJ on Jun 10, 2012

To power wash or not to power wash?

What is the quickest and easiest way to remove mildew from siding? I have heard that power washing can lead to water damage behind the siding. Is there an eco-friendly product to that I can use with a brush to remove the mildew? Also, is there any way to prevent it from coming back?

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Alethea S Springfield, OH

I, too, have the same problem and I've always used a bleach/water solution and scrub brush... and that's not easy for me because of some surgeries on my arms, shoulders etc. The mildew comes back each year and I dread the process. I think I might go to Home Depot and check out the cleaner that also resists the return of the mildew. That would be a happy dance situation!!

on Jun 11, 2012 · Like 1
Carol C Mentor, OH

Bleach/Water will do the trick.

on Jun 11, 2012 · Like 0
Janet R Rio Rancho, NM

what about stucco?

on Jun 11, 2012 · Like 0
Woodbridge Environmental ... Colonia, NJ

Stucco, wood pretty much anything can be power washed if done correctly. The user must remember that water runs down hill,. So using a spray wand with 2,500 psi of water blowing out of the end will work its way up behind the siding real fast. In the Stucco world as well in the wood area you must be careful not to chew up the surface with the pressure. These devices can cut wood and cement blocks in half if not used properly. ...»

You must spray from the top down. using care not to point the wand up so water gets propelled up behind the siding.
Lower pressure works better when ever you can. So choosing the correct tip is very important as well. A large fan pattern softens the pressure quiet a bit so you want to use that type. All to often people use the pin tip that allows the water to spray higher so they do not need to use a ladder, but that results in water under the siding.
Most power washers come with a solvent hose attached. You can purchase cleaning chemicals that this hose connects to and it is drawn up into the washer as you use it. When that is done you let the siding rest for a short while then rinse it off.
A more eco friendly method is to purchase a hose, scrub brush with long wand and some mild soap or detergent solution. Wet, brush and spray.
The reason why mold returns is the area in which the wall faces, its time in the sun and quality of the paint on the surface. Mold requires something to eat and needs moisture to grow. If you can cut back tree branches so you get at least an hour or more sun you will find less mold development. Also as siding ages it begins to collect more dust in the wearing surface. As this occurs this gives the mold something to attach itself to and grow. So in this case simply hose the wall down on occasion until you can get on the house and paint it.
On another topic of siding EIFS or Stucco. The mold sometimes develops behind the lamina or surface of the stucco and stains it in that manner. If this occurs a lot, you need to have the stucco checked for leaks and caulked properly around windows and doors.
Last note, be sure to allow lots of air flow around the siding. If shrubs and trees are real close to house, mold will most certainly develop in that area.

on Jun 11, 2012 · Like 1
Becky H Tampa, FL

I power wash our home, and it has a good deal of lap board on it. You just have to insure you use the correct nozzle/pressure. Start with the soft spray and go to medium if necessary. That way, unless you have some seriously poor paint surfaces, it shouldn't chip or peel your paint.

on Jun 11, 2012 · Like 0
Lori P Colfax, LA

We used to power wash. Now we use a garden sprayer and use bleach water to spray on the siding. Then we use the water hose to rinse it off. Works great!! Just be sure and protect any plants, flowers or shrubs that might get bleach water on them. While my husband sprays the bleach water, I continually spray the landscaping to keep any bleach water washed off. So far it has worked great and bleach is really cheap.

on Jun 11, 2012 · Like 0
Jane P Fishers, IN

Arghh, I had my vinyl siding power washed this spring and a lot of my plants took a beating! The power washing guy used lye!!!

on Jun 11, 2012 · Like 0
Becky H Tampa, FL

Why would he use lye???

on Jun 11, 2012 · Like 0
Bea F Corpus Christi, TX

Bleach and water the best.

on Jun 11, 2012 · Like 1
Diana S Fishers, IN

lye is caustic! I would think the green soap (Palmolive types) and bleach should do the trick...

on Jun 11, 2012 · Like 0
Peace Painting Co., Inc. Alpharetta, GA

A new coat of paint is the best remedy for preventing mildews return. When the mildewcides in the paint from the factory have dissipated, it's time for a new coat.

on Jun 11, 2012 · Like 0
Nicole Y Palmyra, PA

good ol soap and water will work

on Jun 11, 2012 · Like 0
Nichter's Home Services C... Islesboro, ME

Since this photo shows a vinyl siding, some of the generic answers are less than accurate..
I generally disapprove of power washing, but if done carefully with lower pressure and an angle that does not inject water behind the siding it would get the uglies gone.
If this were my job, I would get some Jomax and mix with bleach and water per instructions, spray it on and rinse off with a jet from the hose or a low pressure power washer. ...»

The ingredients in Jomax are activated by the bleach and becomes a mildewcide with a detergent action to free and lift the nasty junk off the surface so far less effort scrubbing or power washing

on Jun 11, 2012 · Like 4
Mirnda S San Antonio, TX

Joe Max & bleach- Spray on w/pump up sprayer.Let stand 5 minutes and rinse off w/sprayer on hose end. Wo0rkes wonders- and also keeps it from coming back , not totally, but not as bad. WE use here in TEXAS ON WOOD SIDING, ABESTOS, VINAL and even concrete.

on Jun 11, 2012 · Like 1
Dee W Rock Creek, OH

We used to wash our house yearly with a brush and bleach mix until we came across a a "siding wash and mildew preventer" sold at Lowe's that is a concentrate you hook up to your hose. Need a cool or cloudy day-spray it on, wait 5-10 min. depending how dirty it is-you can brush it too, just don't let it dry. Rinse it off and you're good to go! We used it 3 years ago and it is time now to do it again. Our home is 2 story, about 1280 sq.ft. and it took 2 bottles.

on Jun 11, 2012 · Like 3
Barlow Builders Inc. Madison, WI

The best way to remove and kill mold is to use ammonia and water. You can buy 3% ammonia at your local grocery store ( 1 gallon ) and dilute it to 3 parts water and one part ammonia. Bleach is harmful if you breath it into the lungs, and kills brain cells etc. Ammonia is safe to breath and will actually kill any spores that are in the lungs and can also be used inside your home in bathrooms or anywhere you have mold if sprayed in a light mist onto the mold.

on Jun 12, 2012 · Like 1
Susan H Jamestown, NY

bleach and water solution works

on Jun 13, 2012 · Like 0
Norma R Snohomish, WA

I use a green product called Bio-Clean. on siding and deck. Safe for plants and pets. Spray on and rinse. Elbow grease and brush will work on stubborn areas.

on Jun 14, 2012 · Like 1
Nichter's Home Services C... Islesboro, ME

Ammonia and chlorine are both on the hazzardous materials list. IOW, if a train car or truck carrying them spills, the area is evacuated and HazMat teams are called in.
I stop breathing around ammonia, due to asthma and reactions.

on Jun 14, 2012 · Like 1
Woodbridge Environmental ... Colonia, NJ

We would never use ammonia for that very reason Nichter. Its far to dangerous of a chemical to use. and you never know what it might react to that may have been spread onto the ground in the past.

on Jun 15, 2012 · Like 1
Barlow Builders Inc. Madison, WI

Our mold remediation expert from the University of Wisconsin Madison recommends the ammonia and water solution. Diluted down to the 3 to 1 mix it is not harmful at all. Ammonia is used in several cleaning products from glass cleaners to counter top wipes and is far safer to use in a spray than bleach. On the container it gives you several ways to use the ammonia to clean, and all of them are listed as to how it should be diluted for each type of cleaning you need. Of course as with any ...»
chemical, you need to use it carefully, and not if you are allergic to that chemical. I'm sure if a train car of bleach spilled, Hazmat would also be called in. It's standard procedure for all chemical spills.

on Jun 15, 2012 · Like 0
Woodbridge Environmental ... Colonia, NJ

Your expert is sort of right on this Barlow, but it does not work on porous surfaces.
Like bleach, ammonia will kill mold on hard non-porous surfaces such as countertops, glass or tiles but it is ineffective at killing mold growing in porous material such as wood or drywall.
Another disadvantage of using ammonia is that it is a harsh, toxic chemical. Make sure you never mix ammonia with bleach because the gas they create when combined is toxic. Chlorine mixed with ...»
ammonia was even used as a chemical weapon during World War 2.
Additionally, although ammonia can kill surface mold, dead mold and dead mold spores are still allergenic so you will need to make sure to remove them afterwards.
How to Kill Mold with Ammonia
To kill mold using ammonia, create a solution of 50% clear ammonia and 50% water in a spray bottle and spray it on moldy areas.
Make sure the ammonia you use says "clear ammonia" on the label.
Leave the area for a few hours before wiping and rinsing.
Often detergents or mold cleaning products will contain ammonia. In that case just follow the directions on the label and be sure never to mix it with bleach.
In my business which does this type of work, I would never use the stuff as its way to difficult to deal with, you must wear special breathing equipment which we do, but must add filters to prevent breathing of the fumes that are given off. And because of the risk of other fumes that can result when ammonia mixes with them we just do not do it. Its one thing to wipe a counter or some other hard surface, but to do an entire wall on the outside of the house. It simply should not be done.

on Jun 15, 2012 · Like 0
Cheri G Lake Charles, LA

Every year I clean mine with a bucket bleach water and a broom very easy you just hose it down and get your brush in their brush it has it off and it's done once a year

on Jun 15, 2012 · Like 0
Terri J York, PA

Just powerewashed my siding and deck w/ combination of bleach, soap and water. Used a scrub brush, and can't see any sign of moss, algae or dirt yet.

on Jul 06, 2012 · Like 0
DutchMolly Branford, FL

I have found the easiest and most cost effective way is to use Oxiclean -- mix it in a bucket with water and use a rag or long handled brush (RV brush with extending handle works great). It immediately removes the mildew and stains and doesn't harm the vinyl finish. I do my manufactured home twice a year with the method -- easy peasy!

on Mar 05, 2013 · Like 0

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