Painted Wooden Siding

Bob McCay

New member
We are cleaning a roof for a customer who would also like us to remove the mildew from his painted wood siding. Since I am pretty much a "roof guy" I need to know the best formula for cleaning his siding. Any ideas?
 
House Wash Mix

Bob, there are any number of recipes available for cleaning house siding. Most contractors use some mix of soap and bleach. I recommend a solution where the bleach is between 1% (normal concentration) and 3% (for extreme problems) and the soap is a degreaser. Washing houses is great work, highly satisfying. There are some different techniques used for house washing - some folks use shooter tips and some use X-Jets.

Do a search here for house wash recipes, and you will find a lot of information.

The process is simple: apply a good strong cleaner, allow it to dwell on the surface for 10 minutes or so, and then rinse off. As always, soap from the bottom up and rinse from the top down. The bleach kills the mold and "breaks" the soil. The soap lifts the soil from the surface and allows you to rinse the side clean.

If you have any other questions, feel free to call me.
 
The most important thing to remember is...no pressure! Seriously, if you can't hold your hand in the spray, you are using too much pressure. Let your chems do the work.

P.S. I have heard soap from bottom to top and rinse from top to bottom for years, but I have never noticed a difference. I usually wash from top to bottom, but sometimes I wash from side to side.
 
Just like the karate kid, spray on rinse off, spray on rinse off, always with low pressure, dwell and letting chems do the work.
 
All of the houses I do are done by ds'ing sh and dawn. Start off with a weaker ratio on the sh if your unsure about damaging the painted surface. Be sure to check for flaking paint, chalking etc. I would also be careful around front entrance ways. Some ceilings are made of green board which cannot take being soaked and or much pressure. Also be careful of hardware around front entrance and other doors. Some expensive homes have hardware which can be made from substances such as nickel plating which will not stand up all that well to any bleach solution. Just some things to consider. Good luck with the job. Post some pics of your work when your done. :)
 
Bob, there are any number of recipes available for cleaning house siding. Most contractors use some mix of soap and bleach. I recommend a solution where the bleach is between 1% (normal concentration) and 3% (for extreme problems) and the soap is a degreaser. Washing houses is great work, highly satisfying. There are some different techniques used for house washing - some folks use shooter tips and some use X-Jets.

Do a search here for house wash recipes, and you will find a lot of information.

The process is simple: apply a good strong cleaner, allow it to dwell on the surface for 10 minutes or so, and then rinse off. As always, soap from the bottom up and rinse from the top down. The bleach kills the mold and "breaks" the soil. The soap lifts the soil from the surface and allows you to rinse the side clean.

If you have any other questions, feel free to call me.

How do you apply your cleaning solutions?
 
You have gotten a lot of good input here. Let me add to it a little.

I start by mixing up the right amount of house wash mix (usually around 10 gallons, calculated by using 150 sq. ft. per gallon coverage). I shoot that mix on a side of the house using an X-Jet.

A lot of guys will suggest that you use a shooter tip and downstream the cleaner (instead) to save the cost of an X-Jet, but I personally don't recommend that. There are posts today on this BBS explaining that hoses, swivels, and quick-connects can be damaged surprisingly quickly by downstreaming strong bleach, and the replacement cost for these wear items with stainless can be significantly more expensive than the difference in cost between an X-Jet and a shooter tip. Either method will work, and everyone has a preference about which way they like to work, so pick yours.

No matter which way you go, X-Jet or shooter tip, be sure to arc your spray. Houses are rain-tight but not water proof. That means that water falling from above (rain) will not enter the house or affect the construction. Shooting up at a house from the ground, on the other hand, can force water behind the siding and through windows. Arcing your spray out a couple of feet from the house will give your cleaner an almost rain-like landing on the siding. Practice makes perfect.

Back to the topic, if you use an X-Jet you need to figure out your dilution rate. There is a calculator for your house wash mix on my web site here near the bottom of the page.

By this calculator, if you are using a 4 GPM pressure washer, you would mix 1 gallon of soap with 2 gallons of 12% bleach and 7 gallons of water and shoot it on with no proportioner. If all you can get is grocery store bleach, then mix a gallon of soap with 4 gallons of 5.75% bleach and 5 gallons of water for your mix. That mix gets the bleach on your siding to around a 1.5% concentration, which is adequate power to attack dirt and mold.

After dwell times of around 10 minutes, the house siding can be rinsed off. All the mold and dirt will rinse away. Repeat this process on all four sides of the house, and move on to the next job.

Good luck in your business!
 
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