One way to keep your concrete driveway, walkway or walls looking good is to wash them and seal them every 2 to 3 years. Concrete sealer helps prevent water from creeping into the small pores and imperfections that lead to cracks and crumbling. Sealer also helps prevent stains from setting in on the concrete. Sealing concrete after pressure washing is similar to painting walls in your house.
Allow the concrete to dry completely before sealing. If possible, seal in the mid-morning or before the sun is directly over the concrete. This gives you an opportunity to apply the sealer without it drying too quickly. Sealer that dries quickly often leaves behind unsightly streaks or lines.
Open the bucket of sealer, and mix it thoroughly with a wooden paint stick. Screw the handle extension into the handle of the paint roller. Wrap the connection between the paint roller handle and the handle extension with duct tape to help ensure a tight fit.
Slip a medium-nap roller onto the paint roller. A medium-nap roller often rolls better on concrete and evenly distributes the sealer even in the small pores and pockets of imperfections.
Dip a paintbrush into the sealer, and scrape the inside of the container with the bristles to remove excess sealer. Paint corners and edges of the concrete in a thin even layer with the paintbrush. Extend the sealer at least 6 inches from corners. This helps to blend in the sealer with the roller later.
Pour sealer into a standard paint tray. Load the roller with the sealer, using the ribs on the paint tray to remove excess sealer. The roller should be saturated but not dripping with sealer. Roll the sealer onto the concrete in a "W" fashion, just as you would when painting a wall. Be sure to cover the concrete completely, overlapping roller strokes to blend one coat with the next.
Apply the sealer as near as possible to corners with the roller, blending the fresh sealer over the area brushed earlier. Allow the sealer to dry completely, and apply a second coat if necessary.