Tape the glass and the wall siding. But leave a 1/16th inch gap between the tape and the concrete—this prevents paint from seeping under and creating a glue seal that peels later.
Now go outside and glare at your windows. I bet you can’t unsee the sills. 😉 painting concrete window sills
Look for “100% acrylic latex” formulated for concrete, or better yet, a specialized elastodynamic paint that bridges hairline cracks. The 5-Step Process (Do Not Skip #2) Step 1: The Deep Clean You aren’t just wiping off dust. You are removing the "chalk." Mix TSP (trisodium phosphate) or a concrete cleaner with water. Scrub with a stiff brush. Hose it off. Let it dry for two sunny days. Tape the glass and the wall siding
Let’s fix them permanently. A freshly painted sill doesn’t just look clean. It creates contrast against your siding and glass. Whether you go with crisp white, a bold charcoal, or a color that matches your trim, fresh sills make your windows look bigger, brighter, and newer. It adds curb appeal for about the cost of a pizza. The One Rule You Cannot Break Concrete breathes. It holds moisture. If you use standard house paint (acrylic latex), that moisture will try to escape, push the paint off, and you’ll get bubbles and flakes within six months. I bet you can’t unsee the sills