Concrete facts will ensure summer project succeeds - June 21st 2013
From the calls to my office it is obvious that homeowners have begun to look at the exterior of their homes and begin to plan their summer projects. Patios, decks, walkways and driveways are common places where concrete and concrete products are used. Concrete can vary in its use and appearance. You may be familiar with terms such as exposed aggregate concrete, concrete paving stones, stamped concrete, and smooth / broomed finished concrete. Each type of concrete product and finish has uses which are better suited to it.
First of all, you never place new concrete over old, you must remove the old concrete first. It is very important that the substrate under the proposed slab is prepared properly. The substrate surface must be compacted properly using a mechanical plate compactor. Drainage must be addressed before the concrete is placed. Where is the water being directed? Never order concrete early, make sure the job site is ready before the concrete arrives. Also, what exposure will the surface be exposed to? If you are having a stamped concrete surface installed be aware of how much UV exposure the surface will receive, because the more sunlight the surface sees the more the colour will be affected by fading, requiring additional maintenance. There is no DIY refinishing kit for stamped concrete.
Keep in mind that you should clean your concrete surfaces at least once a year, using a quality all purpose cleaning product, a patio scrub brush, and garden hose. Many people will pressure wash concrete surfaces. If you are cleaning concrete surfaces using a wand-type pressure washer please do so with caution because you can damage the surface if the pressure is too high. The pressure washer wand nozzle should be no closer than three feet to the surface. If you use a pressure washer on a paving stone surface you run the risk of blowing all the sand out that has been placed between the joints causing settlement and pooling areas to develop. Do not pressure wash paving stone surfaces.
I do not recommend sealing new concrete surfaces until they have been in place for at least 30 days. Before sealing, you must acid wash the surface to etch the concrete to enhance the penetration of the acrylic sealer. Acid wash the surface, using 2/3 water & 1/3 Muriatic Acid, be sure to add the acid to the water, NOT the other way around. Caution: Wear safety glasses, clothing & rubber footwear and gloves when working with Muriatic Acid. Allow to sit until a foaming action occurs, scrub with a stiff bristle patio brush and then rinse and allow to dry. It is best to apply the sealers using a low-pressure garden sprayer, or puddle on the surface and spread with a 10mm roller. Do not seal concrete in direct sun, if it is sunny the surface will be warm and will cause bubbling or peeling to take place. Morning or early evening is the best time to seal concrete. Consider adding a non-slip product to the concrete sealer prior to applying such as SharkGrip, especially sloping traffic areas.