Need advice on cleaning oxidation off a metal roof to prep for repainting

Trainerboy

New member
The job is a large Charlie's Chicken restaurant with a metal roof. It is heavily oxidized but otherwise in good shape.
I need to pressure wash it to prep for repainting.


My plan was to use a boom lift, a turbo nozzle, and time.


My equipment is a hot water, 8gpm, 3500 psi skid. I didn't plan on using chems or hot water. I just planned on blasting the oxidation off with some up close and personal love from my turbo nozzle.


I need advice.
Is my plan on target or do I need to rethink it? I also need advice on pricing this job. The owner is a close personal friend so walking away is not an option. I'm including a picture but it doesn't show some of the headaches I'll be dealing with. There are some neon lights and security cameras I will have to work around. Since I'll be in a boom lift I wondered about using my 19" WW classic surface cleaner. Has anyone ever tried it?


Remember, I'm prepping for a painter to come behind me. I'm not worried about making it sparkle when I'm done. My job is to remove the oxidation, clean off all the bird crap, and clean the black off the roof around the vent hoods.


Anything helps.
Thanks
 

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Does it need painting or does it actually just need cleaning?

It needs to be repainted bad. That picture is old. It has heavy oxidation in it. The owner has been planning it for a couple years. The only actual cleaning is around the vent hoods and bird crap. The main goal is to remove the oxidation.
 
If I were you I would tell the owner to have the painter do his own prep work. Especially if he's a good friend of yours. If you've never done this before, this is not a good job to cut your teeth on. Think about not letting your friendship get strained over this. Ask your friend if once he finds the painter you can watch how they prep and remove the oxidation for painting.
 
If I were you I would tell the owner to have the painter do his own prep work. Especially if he's a good friend of yours. If you've never done this before, this is not a good job to cut your teeth on. Think about not letting your friendship get strained over this. Ask your friend if once he finds the painter you can watch how they prep and remove the oxidation for painting.

The painter doesn't have a machine that will hold up to the task. The painter is a friend of the owner too. I have experience with roofs just not metal roof oxidation removal. Everyone keeps telling me to walk away. I just need advice on methods.
 
If its the paint thats oxidized I would use chems, maybe a caustic soap and let that do all the work, then rinse and done.
 
If its the paint thats oxidized I would use chems, maybe a caustic soap and let that do all the work, then rinse and done.

I wondered about a strong mix of sodium hydroxide and heavy snot through my roof pump. I just wasn't sure the caustic would get the job done on the oxidation. That's the kind of advice I'm looking for, thanks.
 
Personally......I'd 2 step it but use a high ph soap as the second step. You'll see all the chalky paint turn bright again. I agree that it's probably not a good practice job for you though. If you don't do it right the paint won't stick then your buddy is mad at you and the painter!
 
The painter doesn't have a machine that will hold up to the task. The painter is a friend of the owner too. I have experience with roofs just not metal roof oxidation removal. Everyone keeps telling me to walk away. I just need advice on methods.

There's so many variables to this than just methods....methods minus the experience equals disaster sometimes.
 
What if a roof just needs oxidization removed, not painting. My church just added an extension, and the new metal green Roof looks bright and shiny, while the old section looks dull and dark.

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A good alkaline detergent works well if you rinse properly the paint will stick very well (assuming the painter uses the correct paint)> it is important to remove all the grease and oils from the surface as well as any organic matter such as sap, moss,mildew etc. Two step would be the best method in my experience as it both cleans and neutralizes in one process. I would also avoid the turbo nozzle it would be a little too aggressive I believe. If you use a caustic be careful not to make it too strong or you may damage the surface. Also remember it will be running off the roof you don't want to damage the surface below. Treat an area and pattern clean with a wand an area you can complete before it is. Most important is to make sure you rinse well residue left behind can cause it to peel especially the oils by he venthood.
 
When we do metal roofs we make our mix 40% SH and 60 water and alway jetX plus never step a foot on metal roof. Our SH is 15%. Also I would rent a 35' towable lift and charge $1200 in our area. Six hour job.
 
How did this go?


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It went great. I went with my first instinct and used a turbo nozzle with no chems. The only problem I had through the whole job was the boom lift breaking down. The painter starts tomorrow morning.

Thanks for asking
 
It went great. I went with my first instinct and used a turbo nozzle with no chems. The only problem I had through the whole job was the boom lift breaking down. The painter starts tomorrow morning.

Thanks for asking

Glad it worked out Got any before and after pics to share?
 
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