Yes, You Can Paint Exterior Concrete
Concrete is a popular building material because it is inexpensive and durable. Plain gray exterior concrete -- whether in poured-in-place, precast, or block form -- tends to be a little boring to look at, but did you know you could paint it?
You'll need some special supplies and techniques to cover concrete's rough texture and to help it hold up in any weather. The brilliant results are worth it, though. Just think of the cute and colorful cottages so popular in Florida -- they're made of hurricane-resistant concrete painted in all kinds of fabulous pastel hues and they look great. Here's a step-by-step guide to painting outdoor concrete walls, floors, and driveways.
- Allow yourself plenty of time to get the job done right. This is not a quick, one-Sunday-afternoon project. You will need to wait at various stages along the way, while the concrete dries, or the primer or paint cures.
- Clear the space. The paint is going to have to cure for as long as a week after you apply it, so that means you'll have to find an alternate parking spot for your car if you paint your driveway ... or store outdoor furniture when it's your patio that's about to be refurbished, to name two examples.
- Clean up. Scrape off moss and pull weeds that may be growing on or near the concrete. Use a pre-paint cleaner to get rid of dirt and grease so they won't cause the paint to discolor. Strip off any old, peeling or flaking paint with a scraper, wire brush, and sandpaper. Then finish up with a pressure wash. Make sure the concrete is completely dry before you begin to paint.
- Repair any holes. Fill in all deep cracks, holes, or uneven areas in the concrete with concrete patch or mortar, applied with a trowel and allowed to dry as per the manufacturer's directions.
- Seal the concrete against moisture, when painting a previously unsealed house wall or other surface.
- Prime your concrete surface to fill in its pores and help paint adhere. Apply exterior grade concrete block filler, which will require 2 hours' drying time and another 6 hours before it can be painted.
- Don't use regular exterior paint -- it's not made for concrete and will tend to crack and peel as the material expands and contracts. Instead, choose dedicated driveway or masonry paint (aka "elastomeric"), which may be tinted to a color you choose. Because this is much thicker than standard exterior paint, you'll need special equipment. Look for masonry paintbrushes and "texture" or "high capacity" rollers. Attach a long arm to your roller or an extender to your brush to make it easier to cover large areas.
- Add masonry paint thinner to the paint for your first coat and mix well. Apply paint smoothly and evenly. You are likely to need two or more coats for proper coverage. Let dry for at least several hours (check instructions on the paint can) before applying an additional coat. The second and any subsequent coats do not require thinning.
- Apply concrete sealant to protect the paint and make your handiwork last longer, after the final coat is thoroughly dry. Purchase sealant in your choice of glossy or matte finish, and apply with a brush or roller. A second coat may be advisable in areas with heavy vehicle or foot traffic or where furniture is frequently moved across the floor, such as a driveway, swimming pool surround, or patio.
- Allow the paint to cure for three to four days for an exterior floor, or a full week for a concrete driveway, before you start to use the good-looking new surface.
For expert concrete installation and finishing, contact a professional concrete contractor.
Laura Firszt writes for networx.com.
Updated January 31, 2018.