Stained concrete outside helps make the concrete more pleasing. It is one of the easiest DIY projects as the prep work and equipment needed to stain concrete is minimal. There are a few guidelines when prepping the concrete before staining:
- Pressure washing will remove most stains from the concrete. Be careful not to hold the nozzle to close to the concrete or you will etch an unwanted pattern that will show up when finished staining and sealing the surface.
- Oil stains can be faded with degreasers found at the hardware store. Be sure to thoroughly rinse the surface afterwards, because the degreasers will be very sudsy. The oil might not come out on the first try, a couple of tries might be needed. Some time you will be left with a shadow of where the oil stain was.
- Hard water stains can be removed with CLR or similar products, but do not use if you are planning on staining the concrete with an acid stain. This will deplete some of the lime the acid stain works with to produce the color in the concrete. If you need to use CLR you will have to use a water or solvent based dye to stain the concrete.
- For exterior surfaces that are very dirty and after trying the above steps still won’t come clean, the last resort would be to grind the concrete. You will need to rent a grinder from a rental place. This will take the top surface of the concrete off, so you will see some aggregate in the concrete.