How to Paint Rusty Metal Lintels: An Easy Solution

Metal lintels — the structural beams above windows and doors, often visible on brick homes — are prone to rusting over time from ongoing weather exposure, and painting over that rust without addressing it first is one of the most common reasons a lintel repaint fails quickly, with rust bleeding right back through within months.

1. Remove loose rust and failing paint first

A wire brush or wire wheel attachment, followed by sanding, removes loose rust scale and any peeling or failing existing paint — this needs to happen before anything else, since painting over loose rust just traps it under the new paint rather than addressing it.

2. Treat remaining rust with a rust converter

Following the same rust-treatment approach covered for other rusted metal surfaces throughout this site, a rust converter applied to any remaining rust that couldn't be fully removed mechanically chemically stabilizes it, converting it to a paintable surface rather than leaving active rust that will continue spreading under the new paint.

3. Prime with a rust-inhibiting metal primer

A dedicated rust-inhibiting primer, applied over the cleaned and converted surface, provides both a proper adhesion base for the topcoat and genuine ongoing corrosion protection — this is not an optional step to skip for the sake of speed given how exposed lintels typically are to ongoing weather.

4. Apply a durable exterior metal paint

A paint rated for exterior metal use, formulated to handle UV exposure and weathering, holds up considerably better on an exposed lintel than an interior-rated or general-purpose paint not designed for constant outdoor exposure.

5. Check for and address the underlying moisture source, if identifiable

If the lintel's rusting is being driven by a specific ongoing moisture problem (poor drainage, a gap allowing water to collect against the metal), addressing that root cause, where practically possible, gives the fresh paint job a genuinely better chance of lasting rather than facing the same rust-causing conditions again.

6. Inspect and touch up periodically

Exterior metal lintels benefit from periodic inspection (checking for any new rust spots forming, particularly at joints or where the paint might be thinner) and prompt touch-up of any small issues found, which is considerably easier and cheaper than addressing a fully rusted-through repaint situation down the line.