It’s concrete: It’ll last forever…right?
Let’s make sure we’re all on the same page here. Concrete is a very durable, strong and long-lasting material which is why it’s used in foundations of buildings, as roads and driveways, and as floors, patios, etc. However, after years of exposure to the elements and disuse, concrete will break apart and crumble, leaving evidence of its form, but no longer standing or whole. Don’t want the Grand Canyon running through your driveway or patio? How do you prevent it from getting chipped, broken, pitted or cracked? It’s not rocket science! In fact, breathe easy, it’s really quite simple! Seal it.
Proper care and maintenance of concrete involves sealing it. Concrete surfaces are susceptible to water because it is a porous surface which allows water to move in and out of it. This movement of water coupled with fluctuating hot and cold weather can weaken the integrity of the concrete. Other things can mar the appearance and composition of your concrete such as: oil spills or other engine liquids used in vehicles that may drip or leak onto a concrete driveway, spills of paint, stain or other products used in the upkeep of the exterior of your home or business, dirt accumulation and regular traffic on your concrete. Sealing concrete protects it and extends its life. I think of it as similar to taking care of your vehicle’s appearance – washing it, to clean off the dirt and road salts and other corrosive elements it is exposed to from driving it around, and then applying a wax to protect and preserve the color from fading and to repel the dirt and grime from the road for awhile. Who wants to drive around in a rust bucket? To keep your concrete intact and looking good you need to treat it the same way by sealing it.
Sealers are either topical or penetrating sealers. As you might guess, a topical sealer sits on top of your concrete, usually by forming a thin film that acts as a barrier between the outside elements and the actual concrete; a penetrating sealer actually permeates into the concrete and is virtually invisible when dry. Topical sealers can be either solvent-based or water-based and are used to protect and enhance the appearance of stained, stamped or other decorative concrete, more often used indoors; while penetrating sealers are typically used on exterior or non-decorative concrete, especially since they don’t create a film on top of the concrete that may add to the slipperiness of the concrete. Types of topical sealers include acrylic, polyurethane and epoxy.
• An acrylic sealer can be used when economy and easy application are necessary, either on an interior or exterior surface. It is a UV resistant, non-yellowing, protection against water and chloride intrusions that also allows for moisture in the slab to escape. Acrylic sealers, when applied, generally dry to the touch within an hour. Because acrylic is a thinner sealer, it wears faster than other sealers and will require reapplication sooner.
• A polyurethane sealer has a protective film that is about twice as thick as an acrylic sealer and offers excellent resistance to abrasion and chemicals. Polyurethane comes in a range of sheens from high gloss to matte, is transparent, non-yellowing and highly durable. They are, however, moisture intolerant until properly cured. This means that upon application, if it comes in contact with moisture or water, it will create a chemical reaction that results in foaming and bubbling of the sealer. Polyurethane also does not allow moisture vapor in the concrete to evaporate out, which could cause problems in an outdoor concrete surface, i.e. a driveway or patio.
• Epoxy sealers are protective films that are hard, long-wearing, and abrasive-resistant. They are very good at repelling water and are much harder than acrylics. Most epoxies are glossy and can be clear or pigmented. Water-based epoxies bond well to concrete and provide a clear finish, but are nonporous and do not allow trapped moisture to escape. Epoxies are generally suitable for interior use because they are susceptible to yellowing with UV exposure.
A penetrating sealer is invisible protection that penetrates into the concrete to form a chemical barrier that shields against moisture penetration and de-icing chemicals. They are breathable, meaning they allow moisture vapor to escape, and are commonly used outdoors because of the excellent protection they provide against harsh exposure conditions, e.g. corrosion and freeze-thaw damage. Some common penetrating sealers are: silanes, siloxanes and silicates. These are good for use on driveways, patios, sidewalks, pool decks and other exterior concrete surfaces.
With simply a little care and maintenance by sealing and protecting your concrete, you will be able to enjoy it for years to come!