Although some people might consider this a difficult project, there are a number of ways one can avoid mistakes when installing do-it-yourself concrete countertops. One important tip is making sure that the existing kitchen cabinets can support the weight of concrete countertops, which might be much heavier than the existing countertops. Also, the cabinets should be level to avoid damaging the new countertops when they are installed. Finally, the countertop should be poured in sections less than 8 feet (2.4 m) long and should be thoroughly secured to the cabinets using plenty of silicone caulk. Many people may consider this project to be worth the effort, because successfully installing do-it-yourself concrete countertops can yield beautiful and unique results, and concrete can be a more affordable material than granite or other types of high-end countertops.
Before installing do-it-yourself concrete countertops, it's a good idea for one to verify that the existing kitchen cabinets can support the weight of concrete. If the weight limit is not known, the cabinet manufacturer or carpenter should be contacted. If the new concrete countertops will exceed the weight limit, they sometimes can be reinforced by securing sheets of plywood to the top.
Attaching plywood to the top of cabinets can also help to level the cabinet surface. If do-it-yourself concrete countertops are installed on top of uneven cabinets, the countertops can crack or warp. In addition to using plywood, the cabinet surface can also be leveled by wedging wood or plastic shims into any spaces between the countertop and cabinet. Sometimes, installers also level the surface using decking screws.
After the surface is determined to be level, the countertop should be thoroughly secured to the cabinet surface using silicone caulk. Large dollops of caulk should be placed all around the perimeter of the cabinet surface. Not properly securing the countertops to the cabinet can cause the concrete countertops to warp or crack as they cure.
For large areas, it's a good idea for installers to create smaller sections of do-it-yourself concrete countertops, because pieces longer than about 8 feet (2.4 m) might be more likely to break or crack. After the countertops are set, the seams in between these smaller sections can be sealed using clear silicone latex caulk. A colored caulk that matches the countertop can be used.
The seams can be sealed by applying painting tape to either side of the seam and then running a line of caulk over the seam. The line of caulk can be smoothed by running a finger over it. Finally, the tape should be removed when the caulk is dry.