How to Make Concrete Countertops

Concrete countertops are a cost effective and aesthetically pleasing alternative to the traditional laminate or granite counters that are so popular now in bathrooms and kitchens. Since you have the option of creating any shape and size you wish, consider this versatility a great way to exercise creativity.

Things You'll Need

• Workspace with plenty of ventilation
• Premixed concrete rated at 5000 PSI
• Premixed or precut reinforcements
• Coated particleboard
• Plywood
• Pneumatic stapler
• Measuring tape
• Notepad and pencil
• Saw
• Channel for leveling the concrete once in the mold
• Dropcloths
• Crowbar
• Sandpaper
• Acid wash
• Water
• Finishing polish
• Plenty of friends to help you lift the finished product and install it

Instructions

1. Take detailed measurements, using the measuring tape, of the area where the countertops will sit. Remember the adage to measure twice and cut once.

2. Make a scale drawing of the countertops with your pen and notebook. Using lined paper can make your job a lot easier, especially when working with a counter space that has a lot of right angles.

3. Measure any openings you need to leave in the concrete countertops. This includes the opening for the sink and any recessed areas you wish to have, such as for an enclosed knife block or soap dish.

4. Make a mold for your concrete countertops by sawing the coated particleboard for the perimeter and bottom. With the pneumatic stapler, connect the sides to the bottom. Think of this step as making a tub that will contain the wet concrete and shape the form of your counters as the concrete dries. Rely on your scale drawing for this step.

5. Craft the open spaces for the sinks and other inserts by making their spatial equivalents out of plywood. Attach the plywood space savers to the particleboard with the pneumatic stapler. This is a crucial step; failure to measure carefully and repeatedly may lead to a lot of wasted concrete or oddly shaped counters.

6. Mix the concrete according to the instructions set forth by the manufacturer and pour it into the mold. Stop periodically and add the reinforcements you chose. Polypropylene fibers are easier to work with than rods, but depending on the size of the concrete countertops, you may need to use both. Tamp down on the concrete to discourage the formation of air pockets and bubbles below the surface. Level the surface continuously with the channel. Continue the process until the concrete is densely packed into the mold and the surface is perfectly level.

7. Place the dropcloths loosely over the molded concrete. The goal is to slow down the curing process, ensuring that the inside of the slab dries to the same extent as the exterior of the countertops.

8. Remove the outer mold after four to five days. Use a small crowbar to separate the particleboard where it is stapled together. The plywood inserts are not removed until the countertops are installed and you are ready to put the sink in place and any other gadgets for which you left space.

9. Sand sharp edges around the corners and remove any excess concrete that may have dried in place. Prepare the acid wash according to the manufacturer's recommendation and apply it to the countertops. Finish with a water rinse and let the countertops dry naturally.

10. Mix the finishing polish carefully. Since this is the layer that contains the pigmentation and will pretty much determine the appearance of the concrete countertops you are making, extra care is highly recommended. Apply the finishing polish and follow the instructions given by the manufacturer with respect to sanding and cleansing.

11. Enlist the help of your friends and install the concrete countertops you just made.

Tips & Warnings

• If you prefer to have a lighter color for your concrete countertops, it is best to create your own mix. Experiment with various different mixes and add sand, gravel and other additives. Pour small batches the size of a 1-inch-by-1-inch patch and see how you like the effect.

• Practice mold making on a small scale first, just to give you a feel for the way the concrete will pour and how the inserts will leave open spaces. If you ever considered making a few stepping stones for your garden, this might be the time to make them!

• It takes 25-30 days for concrete to cure completely. Until then, it is hard to determine what the final color of the finished countertop will be.

• Do not work in an enclosed space without adequate ventilation. The fumes of the acid wash and also of the curing concrete may be harmful to your health.

• Never mix concrete, sand a surface or apply acid wash without wearing protective eye goggles, a breathing mask and gloves.

Resources

• Read this Article in Spanish
• Inspiration for your concrete countertops
• Unique blueprint ideas