Concrete blocks are always in demand. They are used to build housing, fences, and in gardens. As a business, making concrete blocks requires very little to start in terms of money and time. Using hand molds, one person can make up to 100 concrete blocks per day. Once they're selling, a successful entrepreneur can move from hand molds to machines, churning out up to 1,000 blocks a day.
Clear a place in your garage or other semi-protected area and set up the concrete molds. If you do not have molds, use a Styrofoam block as a model. Measure around the block. Cut plywood or 2 x 4's to fit. Join the cut pieces together to form a box with a bottom, but without a lid. The average size for a concrete block is 300 mm long, 200 mm wide, and 150 mm thick.
Line the molds with flexible plastic sheeting, such as trash bags or cling film.
Make the concrete. In a large container, combine 1 part cement , 2 parts sand and 3 parts gravel. Begin slowly adding water to the mixture, stirring constantly. When the mixture is pliable enough to place in the mold, stop adding water.
Stir until the concrete is uniformly mixed. Then stir for another 2 to 3 minutes. This starts the hydration process which is what causes the concrete to harden.
Scoop the concrete into the mold using a trowel. Tap the edges of the mold to make sure there are no air pockets. Run a smooth, flat board across the surface of the wet concrete block to level.
Leave the concrete alone for 24 hours. Remove the block from the mold. Protect new concrete blocks from the rain and extreme temperatures for 3 days. At the end of this time, they will be ready to sell.
Advertise your business. Once you have a reasonable quantity of concrete blocks, take out an ad in your newspaper, post fliers on the bulletin board at the garden center, and set up a website offering your services. By reducing the cost of transporting heavy, bulky blocks, you will be able to offer a competitive price and you'll be better able to personalize the product to meet the needs of the customer.
If you are not confident in your ability to make concrete, use premixed products.
The higher the cement to sand ratio, the stronger the concrete will be.
Buckets will give more precise mixing measures than shovels will.