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 tin siding.
For steel use a latex bonding primer instead of a regular metal paint primer.
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.
What is the best paint to use on metal siding.
When it s time to.
When ready pour the primer into the paint container on the sprayer or pour the primer into the paint tray.
If your siding is horizontal paint left to right.
The homeowners hated the look but the metal was still in decent shape and they didn t want the expense of re siding the entire house.
As long as the siding is clean you won t need to use a primer unless raw metal is exposed.
Paint in long even strokes making sure not to overdo it.
If your paint is dripping then you have too much.
Work from the top down to eliminate dripping paint from ruining your hard work.
Finally since metal is such a good heat absorber avoid painting siding while it s getting direct sunlight.
Tin or aluminum siding is low maintenance and doesn t need to be painted as frequently as wood but over time even the best paint can fade chip or break down into powder.
If vertical paint up to down.