DIY Network

Custom Concrete Countertop, Part II A concrete apprentice puts the finishing touches on a custom countertop he put together for a residential bathroom. From "Trade School" episode DTRS-408

Concrete apprentice Mike Ferrara finishes out the custom countertop for a residential bathroom vanity.

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Materials:

Portland cement
sand
silica powder
coarse aggregate
several plastic buckets
portable cement mixer
wheelbarrow
shovel
float
metal scoop
grinder with diamond-polishing pads
abrasive pad
power buffer

Steps:

1. With the form ready, Mike prepares two batches of concrete. First, he portions out Portland cement, sand, silica powder and coarse aggregate into several plastic buckets.

2. Outside the shop, Mike pours the ingredients into a portable mixer. He also adds a special agent to keep the mix from clumping. With the ingredients churning in the mixer, he adds water until achieving the consistency of cake batter and then he dumps the wet concrete into a wheelbarrow.

Figure A

3. Inside the shop, Mike agitates the wet concrete with a shovel and then uses a metal scoop to pour it into the form. Instructor Sam Casto helps by evenly distributing the aggregate with his hands and then pulls up on the rebar so that it suspends in the middle of the liquid concrete (figure A). Then, Sam uses a float to smooth the concrete flat.

5. With the bottom tier full of concrete, he screws three melamine cap-boards onto the openings away from the sinks. These caps prevent the concrete from overflowing as he adds to the second tier around the sinks.

6. After mixing a second batch of concrete, he fills in the rest of the form, covering the sink molds. Again, he distributes the aggregate and smoothes the surface with the float. The concrete is allowed to set for a minimum of two days.

7. After the concrete has cured, Mike and Sam unscrew and remove the cap-boards. Then, they flip the heavy slab over onto a wheeled cart and proceed to remove the sink molds.

Figure B

8. To polish the concrete countertop to a smooth finish, Mike uses an abrasive pad and a water-feed to smooth the sides and concave sinks. For the large, flat surfaces, he uses a disc sander fitted with diamond discs of varying grit (figure B). Throughout the polishing, the running water feed helps prevent material from clogging the sanding surfaces.

RESOURCES :
custom concrete countertops — Set In Stone Inc.
E-mail: setinstone@myawai.com
Website: www.setinstoneinc.com