I visited a pressure washer retailer today and purchased a "downstream injector" assembly with a "2.1" spec General Pump brand injector, separate spray tip, and one gallon of soap/surficant to mix with water and some sodium hypychlorite I already have for my pool, which he says will let me use my 3.5 HP Honda gasoline pressure washer for soft washing the vinyl siding of my house. The store manager told me to mix two gallons of 6% hypochlorite with one gallon of his soap/surficant, and two gallons of water, and based on that mixture combined with my particular pressuer washer and the included 2.1 spec injector, that should allow me to soft wash my entire house with the right strength solution. I figure if I can do it myself I can do it more often and for less money than paying chemical wash contractors.

This will be my first DIY attempt. If it works and if I can dial in the least strength solution to minimize inherent damage to surfaces using caustic agents like these, I'm guessing that with the proper chemicals and experience I'll be able to soft wash all kinds of stuff: concrete, brick, my wifes plastic yard furniture, my shed, and anything else.

Besides the obvious of cleaning and rinsing the hardware when finished and wearing eye and appropriate breathing protection (I'm thinking N98 might be good enough, or a charcoal organic vapor mask, not sure which), do you guys have any other advice before I get started ? The last thing I want to do is accidentally damage my house, my lungs, maybe my skin, and most definitely my wife's plants.

So what am I missing for my first attempt ? Any advice is much appreciated.

I use a brand I get at Home Depot (M1 Housewash) that gets mixed at something like 1 cup housewash, 2 cups bleach and 12 or 14 cups water. It does amazing stuff in 8-10 minutes, then wash off with a garden hose. I use my pressure washer for a little more effect but the hose works fine.

The stuff you're using sounds like the same chemicals by a different name but much stronger so I'd be careful at first and let experience guide you.

I've never used a mask or respirator, just careful of the wind direction and staying away from the overspray or mist when applying the chemical.


They make a different version of M1 for concrete. Here's the house version;

https://www.homedepot.com/p/M-...ner-785G1M/100168300