Follow these four simple steps:1. Assure the surface is free of algae, mold, mildew, etc. by using C2 Wood Cleaner. Scrub the affected area with a cleaning mixture and a scrub brush and rinse with a garden hose or pressure washer no more than 1250-psi using wide fan pattern. Leave solution on concrete for 15 to 20 minutes. You can reapply if needed.2. Assure the surface is ready to accept C2 Guard by testing to make sure the product absorbs and does not roll off.3. Apply C2 Guard product when temperature is over 35° and air is dry, with no imminent rain. Use brush or sprayer.4. Apply second coat wet on damp. Do not allow previous coat to dry completely before applying the next coat. Older, porous wood might require additional coats.