Prepping, Priming and Repainting Exterior Metal Siding

By Matt Weber

When the old paint wears away, it’s time to wash away the chalk and apply a new acrylic latex.

The house I’ve been remodeling was built in 1978, and the exterior paint colors did nothing to hide its age. The aluminum siding was a shade of beige that had aged into a dull mustard tone, and the trim was a rust-colored reddish brown. 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. A new paint job was the solution. However, over time the original paint coat of the siding had developed a chalky film, caused by the old paint film wearing away. The chalk had to be removed before slapping on a new coat. We had a lot of prepping and painting ahead of us. Here’s how it went.

Prep School

On any sort of painting project, surface preparation is absolutely critical for any hope of success. Obviously, you need to remove any loose dirt or debris. There was also a lot of shrubbery to cut and remove for unhindered access to the house walls. The chalk that coated the old aluminum siding posed the biggest obstacle for this project. If you wiped your hand across it, you’d draw back a dirty, yellow palm. This stuff seemed to cover every square inch of siding and made for a lousy painting surface.

A pressure washer with a detergent tank is a good tool for removing chalk from the old paint surface.