Handsome, hardwearing concrete walks, steps, and porches will form an impressive entree to any home. To achieve the best looking and most durable outdoor concrete, follow these 7 pro tips. They will help you to understand the steps of readying your surface, preparing the concrete, and taking care of it after it has been laid.
- Prepare the subgrade carefully before laying a concrete walk, steps, or porch. The subgrade should be uniformly compacted to help minimize cracking as the concrete settles. Make sure that your walkway will not be placed close to trees with large (or even potentially large) root systems, which can cause damage to the concrete as they grow.
- The concrete should be formed by mixing ingredients in the proper proportions, according to weight. Eleven percent cement, 26 percent sand, and 41 percent aggregate (crushed stone or gravel), plus 16 percent water and 6 percent air is the formula specified by the Portland Cement Association . Generally, it's best to thoroughly blend the dry components, together with an air entrainment agent, before adding the water. Air entrainment works to increase the finished concrete's resistance to damage caused by freeze-thaw cycling and the application of de-icing salt or other chemicals, while sufficient aggregate aids in forming a strong top layer.
- Use the correct compression strength. A compression strength of 400 PSI is recommended if the concrete is to be exposed to de-icers, which are normally used on residential paths and stairways in the course of snowy Northern winters.
- Don't over-manipulate the concrete or add water when it is being finished. Otherwise, you are likely to end up with a weak, flaky upper layer, formed of only water and paste, which is susceptible to spalling (also known as scaling). Spalling is the chipping and pitting of a concrete surface as the result of extremes of temperature. Although it does not significantly affect the strength of concrete walks, steps, and porches, nevertheless spalling will mar the beauty of the entrance to your home.
- Plan for control joints in walkways and other concrete slab structures. These are weakened lines cut so that the inevitable cracks which form in the concrete will be straight and regular, appearing as part of a preplanned design on the surface rather than a blemish. In addition to the traditional sidewalk score lines, nowadays control joints can be part of a checkerboard pattern, faux stone effect, or other decorative look.
- Allow the concrete to cure properly, starting immediately after it has been finished. This refers to a process of slowing down the concrete's drying over several days that is essential to produce strong, durable concrete. The concrete must be kept moist at all times during this period, especially if the weather is particularly dry and windy. There are several methods of dampening concrete during its curing: hosing it down, spreading with moistened straw or polyethylene sheeting, covering with a special curing blanket, or spraying the newly laid concrete with curing compound.
- Seal the concrete, either shortly after curing or at any point in its lifetime, to safeguard against extremely cold weather conditions and the havoc they tend to wreak.
Laura Firszt writes for networx.com.