ive had both with oxidized metal.

So a quick house wash can make it or ruin it. A test spot may be in order.

We try to steer clear of badly oxidized metal siding because you never know what is going to happen with it. we have had paint roll off with just water at low pressure (500 psi). You cant count on all of the paint on the siding to react the same some will roll off and some wont. You need to let the customer know that they will most likely need to repaint when done then they can make the decision that relieves you of any liability. Put it in writing if you do the job.

Is 500psi really considered low pressure by todays standards? I've just cleaned a metal building that was installed in 1983 if I remember correctly, moderately oxidized and had never been cleaned before. My system runs around 80 psi. and used 1 oz. per gallon of Elemonator in my mix (trying something different AC don't hate me) then washed and Bleachwashed with very good results. Don't have pics ready yet but it cleaned up very nicely and the owners new from the get-go not to expect a newly waxed car when I was done. We also did a demo on the back side that faced the house not the road so they could look at the difference everyday until we did the whole building(he he he ha ha ha)!

Matt what percent mix did you use, I am guessing pretty light like 1%?

Hey Jim,

The percentage of mix is very important but the most important aspect of your cleaning here would be "Communication". Communication is the best possible mix because, like Greg said above, oxidized metal is an unknown. A small test area is not a great indicator of what the end result will be.

Thicker paint in some areas, more sun over there, better shade here.......are all factors. Communicate to your client that your mix can strip off the paint in some areas even if the test areas comes out just fine. Start with a weak mix at .5-1% and be sure to fully rinse when done.

Your client probably already knows they need a paint job but communicate by words and visual stimulation. Take your hand and rub it on the siding and show them what comes off. Show them the palm of your hand. I believe the palm works better then two fingers simply for the dramatic effect of it. The residue all over your hand really drives it home and helps your client understand what they, and you, are up against.

Rubbing your hand also allows you to get a better sense of the condition of the paint. Do this in several areas around the property.

I have a client with just that situation. Paint looks like striped in some areas and ok in others. Its gotta be years of neglect. His home is on the market and I am doing landscaping for him to freshen up the place. He has gm on the north side heavy and scattered throughout the roof as well as something here and there on the siding. I was going to offer roof cleaning but am concerned with doing his siding. Hate to make it look worse, ya know. Thx property is up for a short sale so his funds are limited otherwise I would suggest cleaning and paint to follow.

If by chance he does go for the cleaning and painting I need suggestions on prepping for paint. Bleach wash removal etc.

Jess

Sorry I think I may have hijacked this thread... Doug I did the palm demo by accident. Lol

Hey Jim I used 1.5% with pixie dust, let dwell about 3 minutes rinsed and checked on the worst side then finished the rest of the building with 5 minute dwell time. After drying there was some variation with chalkiness but after bleachwashing it blended it together nicely. It was not perfect but the customer was very pleased and that's all that matters in the end.

People were really talking about pixie dust last fall, but not so much now. I think there is a thread on here somewhere.
Thanks for all the tips and insight.