Step 1: Tools and Materials
In this project I am making 4 concrete tire piers, to support wooden beams, using worn tires from my small car. However, I am only providing instructions and a material list for just one concrete tire pier.
Wheel barrow or cement mixing tub
Steel trowel or putty knife
3/4 inch (20 mm) metal pipe, 3 or 4 feet (.91 or 1.22 m) long; 2 needed
Materials Needed for 1 Concrete Tire Pier:
Rebar supports: 2
3/8 inch (10 mm) rebar, 12 inches (305 mm) long: 3
Old tires: 2, one for the pier and one for the mold. They should be roughly the same size.
40 inch (1 m) roll of tar paper: 1 roll
Duct tape: 1 roll
Plastic garbage bag: 1
Ready-mix concrete: 2- 60 pound (27 kg) bags
Metal anchor suitable for your project.
Step 2: Preparing the Tire for Concrete
Step 3: Bending Rebar
Lay one of the pipes on the ground. Insert the rebar into the pipe leaving 4 inches (102 mm) of the rebar exposed. With one hand, hold the rebar next to the pipe so that it doesn't move. With the other hand, slip the second pipe over the exposed part of the rebar and bring the two pipes together as seen in Photo 2.
Then, place your foot on the first pipe and with your hand, pull the end of the second pipe upward to bend the rebar as seen in Photos 3 and 4. Photo 5 shows the bent rebar. Follow this procedure for the remaining rebar.
Step 4: Setting the Tire in Place to Add the Concrete.
Then place the tire on the mound (Photo 2) and place a level on the top of the tire. Adjust the tire so that it sits level on the mound as seen in Photo 3. Rotate the level by 90° and adjust the tire so that it is level.
Carefully remove the tire and place a garbage bag or piece of plastic on the mound and then place the tire on top of the plastic, as seen in Photo 4.
Use the level once again to adjust the tire so that it is level in both directions. The plastic-covered mound prevents the concrete from oozing underneath the tire.
Step 5: Creating the Mold for the Concrete Section Above the Tire.
Cut a 10 inch (254 mm) piece of the tar paper and fold it in half lengthwise so that you have a folded piece of tar paper that is 5 inches (127 mm) wide and 40 inches (1m) long. Position the tar paper inside the tire bead with the folded edge down and place a piece of duct tape about 2 inches (50 mm) from the end. Tape the tar paper to the tire, taping the free end of the tape inside the tire as seen in Photo 2.
Continue taping the tar paper to the tire at 3 inch (76 mm) intervals all the way around the tire. When you work your way back to the starting point, place the unsecured tar paper behind the beginning edge of the secured tar paper as seen in Photo 3.
Place a long piece of duct tape over the beginning end of the tar paper so that it is taped to the tar paper behind it as seen in Photo 4. Place the remaining unsecured length of tar paper around and behind the secured tar paper and tape the tar paper together so that you essentially have a tar paper ring. You will need to trim portions of the upper edge of the tar paper ring so that the height of the ring is uniform.
There will likely be bulges in the tar paper ring. To get rid of them use scissors to cut through the inner tar paper, in the bulging area, down to the fold and tape the cut so that the tar paper lies flat.
Note: It is convenient to use tar paper because it doesn't readily stick to the cured concrete and is easy to remove. One could use cut up paper grocery bags instead of tar paper but it would stick to the concrete and would require a piece of plastic film to be added to the inner side of the paper before the concrete is added to the mold.
Now carefully place the second tire on top of the first tire so that the tar paper ring fits inside of the second upper tire. Cut pieces of cardboard to the same height of the tar paper ring, which in this case is 5 inches (127 mm). The cardboard is naturally stiff so roll the cardboard pieces into a roll to pre-form the cardboard into a ring.
The cardboard pieces are not connected to each other but are placed in-between the tar paper ring and the upper tire. This is done to add support behind the tar paper ring. Keep adding layers of the cardboard to fill the space between the tar paper ring and the second tire as seen in Photo 5.
Step 6: Adding the Concrete and Metal Anchor.
Continue filling the lower tire with concrete up to the tire bead. Then insert the "L"-shaped rebar so that the long end is buried horizontally into the wet concrete in the tire below with the upper end of the rebar exposed and vertical as seen in Photo 1. Space the 3 rebar evenly in the concrete.
Add more concrete inside the mold filling it up to the upper edge of the tar paper. Use a spare (unbent) rebar to stab the wet concrete so that any voids or air pockets are eliminated.
Use a trowel or putty knife to smooth the upper surface of the concrete and then insert the metal anchor (Photo 2), working it well into the wet concrete as seen in Photo 3. Smooth the surface once again with the trowel (Photo 4).
Let the concrete dry for a few days before moving it. Cover it with a tarp if the temperature gets below freezing. Give the concrete a sprinkle of water each day if the temperature is really hot.
Once the concrete has cured, remove the upper tire and the cardboard. The tar paper should peel away from the concrete but it will still be attached to the tire so you will need a box knife to cut away the tar paper at the edge of the tire.