How to Keep and Protect a Concrete Porch From Weather

Sweep or vacuum the porch to remove all dust and debris. Vacuums work best for removing dust from corners and steps, but if you only have access to a broom, sweep as thoroughly as you can.

Remove stains from the concrete. Once you apply the sealer, existing stains will be sealed into the concrete, so now is the time to remove stains. For grease stains, apply a paste made from water and baking soda to the stain and allow it to sit for 10 minutes before scrubbing it off with a scrub brush. For paint stains, apply paint thinner to the stains with a disposable rag and scrub the paint thinner with a wire brush. If you have mold on the porch, use a pressure washer to remove the mold completely. Allow the porch to dry before moving on to Step 3.

Mix the concrete sealer with a paint stick to ensure that it hasn't separated. Don't shake the can to mix it because air bubbles will appear in the sealer, and the air bubbles could remain trapped in the sealer after it's applied to the concrete, resulting in a compromised seal.

Apply the sealer to the entire surface of the porch. Use a paint-brush or paint roller to apply the sealer. If you have a very large porch, consider using a paint roller with a handle extension to make the job easier. Apply the sealer generously but evenly.

Allow the sealer to dry for two hours. If the porch was very porous or if you expect very harsh weather, apply one more coat after the two-hour drying time. Don't walk on the sealed porch for four to six hours after you have applied the final coat.