How To Polish, Seal And Restore A Concrete Countertop
Concrete Countertop Restoration Tips
By Troy Cantini
Concrete countertops need to be periodically restored to bring back the new look and shine they had when they were first installed. Over time concrete countertops will develop holes, etch marks, stains and blemishes and loose their shiny appearance. It is necessary to periodically fill in the missing concrete, polish and seal the concrete countertop.
The first thing that must be done to restore a concrete countertop is to remove any etch marks, blemishes and stains on the surface of the concrete. Concrete is extremely porous and extremely sensitive to acidic products. It is inevitable the over time the concrete will become stained and etched. A natural patina of etch marks and stains may look ok for some people but over time this natural patina can start to look unsightly and ugly. Also the concrete countertop sealer will break down over time allowing food, stains and bacteria to grow in the porous concrete. It is definately necessary to periodically deep clean and seal a concrete countertop.
After removing the etch marks and stains then all the holes in the concrete must be filled. Acidic food products, water and caustic cleaners will cause holes and divots to form in the concrete. Normal colored cement based grout can be used to fill in these holes and dovots in the concrete. You can also use a white cement and mix it with some powdered concrete color to fill in the holes and divots in the concrete.
A diamond polishing pad must be used along with a variable speed angle grinder to buff out these etch marks and stains in the concrete. A 400 grit diamond pad will remove most blemishes from the concrete. In some cases it may be necessary to go down to a 200 grit pad to remove deep etchings and discolorations. You should put a small amount of water on the etch marks and use the angle grinder to slowly buff out the etch marks and stains. You should periodically dry the etched area and inspect it and then continue buffing out the etched areas until the the countertop has a nice even appearance without any etch marks, stains or discolorations.
Another problem with concrete countertops is that over time holes, divots and chips can form in the concrete that need to be filled. To fill the holes and divots you should mix some white concrete along with some dry concrete coloring powder. You should choose a color that matches your existing countertop or you can also choose to add some color to your concrete countertop. Mix the color by weight with the white cement ensuring that no more than 8% by weight of color is mixed with the white cement. You can also use a normal unsanded grout with a matching color of the countertop to fill in the holes and divots in the concrete.
To apply the colored cement or grout you can use vinyl gloves to smear the cement with your hands over the entire surface of the countertop. Trying to use a grout float or similar tool will put the concrete flush with the cement forming divots in the filled holes. You want a thin layer of cement to sit on top of the countertop so that divots do not form in the filled holes.
Allow the cement to dry for about four hours and then sand the cement down with normal 220 grit sandpaper. A random orbital sanded works best to evenly sand down the countertop but you can also sand it down by hand. Be careful you are not too aggressive when you sand down the countertop or divots will form in the holes you are trying to fill. It is best to leave a slight mound on top of any holes and divots so that they can be polished down with the diamond bit polishing pads.
After you are done polishing the countertop then you are ready to seal it. It is important to seal the concrete because it will be extremely porous and easily stain and etch if it has not been properly sealed. You can apply a concrete countertop sealer like Chens concrete countertop sealer per the manufactures instructions. You should mix the sealer with water and slowly increase the concentration of the sealer on the countertop until you are applying the sealer at 100% strength. This will ensure that the sealer soaks deep into the porous concrete and seals it.
After sealing the countertop you should use some non-toxic food grade wax to polish the surface of the countertop. This wax will add an extra layer of protection to the sealed countertop. You should use the angle grinder along with a soft buffing pad to buff out the wax until a nice even looking shine forms on the countertop. The wax is important because no type of sealer can protect the acid sensitive concrete from becoming etched and stained from acidic food or cleaning products. You should repeat the waxing procedure at least once a month to ensure that the concrete is protected and to keep the concrete countertop looking shiny and new.
After restoring the concrete countertop you should caulk the seam between the countertop and the backsplash and install the faucets and fixtures. To keep the countertop looking shiny and new you should always clean up any food and spills from the surface of the countertop. Also try to avoid getting any type of acidic food or cleaners on the surface of the countertop. Periodically cleaning and polishing the countertop with the food grade wax will help keep the countertop looking shiny and new for years to come.
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