If you did not do a good job of scraping off the old paint or there is chalking that you can t get to come off then you should first paint with a primer.
Painting over painted metal siding.
Start at the top of the wall and across the length of the metal siding.
As with all exterior painting projects proper surface preparation is the key to restoring your metal siding.
The secret to painting galvanized steel is white vinegar.
Galvanized steel should not be painted with oil based paint.
When ready pour the primer into the paint container on the sprayer or pour the primer into the paint tray.
If you have a kitchen then you probably already have this handy solution.
When painting with a brush brush towards the unpainted area and then back into the freshly painted wet surface to prevent lap marks.
Prepainted metallic surfaces can be treated almost like any other basic latex or oil painted surface.
The best way to get this siding clean is to power wash it.
All you have to do is simply apply the vinegar to a clean rag and then wipe down the galvanized surface.
Use the ladder for painting the steel siding on the top and using the roller paint in a horizontal direction.
The key to painting aluminum siding is to get it really clean and to use 100 percent acrylic latex paint.
The paint that you choose will depend somewhat on how well you prepared your metal siding to receive the paint and what the surface of it looks like.
Ensure that you re dealing with aluminum.
Metal surfaces require specialized primer and paint for good paint adhesion.
Also keep a damp rag handy to clean up any wayward drips or splatter.
Then apply the primer to the metal siding in even strokes.
For steel use a latex bonding primer instead of a regular metal paint primer.
Begin by thoroughly cleaning your siding of all loose dirt chalk and other contaminants.
White vinegar is both effective and non toxic so it is much safer to use than your average industrial solvent.
Painting vinyl or another metal material other than aluminum will be greatly different so it s important to be sure of what you re about to paint.
Then put the paint of your desired color in the rolling pan and cover your paint roller with the paint.
Step 4 retouch.
Repeat the procedure until you cover all the steel siding.
Check the label to be sure it s recommended for metal siding.
Before painting you ll still need to do a little.
Paint the steel siding panels using the sprayer.
Many paint manufacturers offer multi purpose enamel or a direct to metal paint.
Expect to pay the premium for good paint.
However if you want to paint over prepainted metal you re in luck.
Aim the sprayer nozzle directly at the panels eight inches from the siding surface.