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How to Make Concrete Countertops


Making the mold for your concrete countertop

Note: I know I have said it before, but you must remain conscious that the mold is a negative image of the concrete countertop.

Place a sheet of the laminate coated MDF on your workbench. It is important that the workbench is sturdy and level.

Clamp the template on top of the melamine upside down. This means that all the notes and measurements that you wrote on the top of the template are now hidden, they are up against the top of the laminated MDF panel.

Note: Use scrap pieces of wood between the clamps and the laminate so that you do not mar the surface of the laminate panel.

Trace the outside of the template, the front, back and sides on to the laminate.

Cut the lamiante coated MDF using a table saw and fine tooth saw blade.

Note: When cutting the piece of MDF set the saw blade to remove the template trace line. It is better to have the concrete countertop slightly smaller than the optimum size rather than slightly larger.

Place the cut piece of laminate panel back on the workbench and place the template on top as before, upside down. With the template in place verify that it is the same size as the template. Trace the length wise position of the sink onto the lamiante. Draw a line on the lamiante defining the center of the sink. The depth position of the sink is not critical, but there are two things that you must take into consideration:

  • There must be enough free space between the walls of the sink and the outside of the sink bowl to allow for the positioning of the sink mounting hardware.
  • The sink should be positioned with a maximum of 4 1/2 inches and a minimum of 1 1/2 inches from the front edge of the countertop.

Note: The hole for the sink can be confusing. The hole allows for the sink edge to fasten underneath the concrete countertop, the sink edge should not be visible when looking down, so the hole in the concrete countertop is the size of the bowl or bowls, as the case may be minus a small overhang. We suggest allowing a 1/4 of an inch overhang all around the sink.

Measure and square the sink opening with the front edge of the template, do not measure from the ends of the template if you did not square the template when you made it. If the template was not square and built to match wall angles the ends of the template are not perfectly square and your sink will be crooked when mounted in the hole.

Mark the position of the faucet and any other accessories that will require holes in the concrete countertop.

Note: We must jump ahead at this point. Most faucets and accessories are designed to fit a countertop that is a maximum of 1 1/2 inches thick, our concrete countertop is 2 1/2 inches thick. Because of the extra 1 inch of thickness, some faucets and accessories will not have mounting stems long enough to go through the concrete countertop, hence you will not be able to fasten them in position. To alleviate this problem you have to place voids in the concrete countertop that will accept the faucet mounting stem and accessory mounting hardware. A 2 inch diameter recess is usually sufficient. However, check the mounting hardware on the faucet and accessories that you have purchased. This is mentioned at this time because the amount of concrete from any void or hole to an edge in the countertop must be a minimum of 1 1/2 inches to avoid cracking. To ensure that the void for the faucet or accessory mounting hardware does not encroach on this 1 1/2 inch distance when you are placing faucets and accessories allow 2 1/2 inches from the edge of the hole to any edge in the concrete.

Continued - How to constructing the mold for your concrete countertop

How to Make Concrete Countertops - Index