Cracking is a natural phenomenon of concrete and should be expected. Control joints, or those straight lines that are usually scored into the concrete, are to ensure that the concrete cracks both where you want it to and in a straight line. Discontinuous cracks and cracks away from the control joints sometimes occur and can be repaired to an extent. If the cracking is too bad you may want to replace the entire slab. Further information on concrete cracking, its causes and cures can be obtained through the BC Ready-Mixed Concrete Association or your local ready-mixed concrete supplier.

Dirt and grime can be easily removed form concrete in a couple of ways. The easiest method is through the use of a pressure washer. Pressure washers increase the water pressure from your household system through a series of pumps. Care should be taken to ensure that the pressure at the end of the washer wand is not above 2500 psi as pressures above this level can harm the concrete surface.

The use of hot water and running an alkali cleaning solution (made for pressure washing concrete) through the pressure washer can be used to enhance the cleaning performance. Note that pressure washing can cause loose or poorly bonded concrete to be blasted away so a thorough inspection of the concrete to be cleaned should be done prior to starting with the pressure washer. A stiff broom and a cleaning solution will also usually do an acceptable job of cleaning most dirt and environmental buildup from your concrete. The cleaner should be an industrial strength alkali cleaner available from your local hardware store.

Some people recommend using acid to clean concrete. This is definitely not the right thing to do as acids react with the cement paste in the surface of the concrete and will eat away or weaken the surface layer of your concrete. Acids are sometimes used on new exposed aggregate concrete as the final finishing step before sealing the surface but this is a specific application and should only be done after consultation with a professional from the concrete industry.

If you are having trouble getting tough stains from your concrete,  follow this link  to the National Research Council Canada for more information on the removal of stains from concrete surfaces.

Once the concrete has been cleaned a good quality acrylic concrete sealer should be applied. The sealer protects the concrete from staining and also makes it a lot easier to clean the next time. Sealers are available in gloss, semi-gloss and satin finishes. A good quality sealer is available from a concrete supply store.

These compounds are typically a pre-blended bagged product, which are designed to bond to the existing concrete and able to be feathered down to the existing slab so that there is no noticeable lip at the interface between the old concrete and the patch. This job is easily within the realm of the home handyman and the materials are again available from your local hardware store. Note that you should be very diligent in following the slab preparation instructions to ensure that a good bond between the old concrete and patch is achieved, otherwise you can't expect the patch to last.