How to Build a Radius Wall

Place the first two courses of specialized precast concrete blocks on top of the patio paving to build the straight wall leading into the curve.

Position the first slightly wedge-shaped starting block of the first course with the raised lip around the center hole facing upward, and the short side of the block facing outward. Place the second block next to the first block the same way, but with the short side facing inward to maintain a straight line. Work from right to left.

Straddle the joint of the first two blocks with the second course starting block, with the short side facing outward and the two semi-circular cutouts on the ends slotted over the raised lip surrounding the hole in the underlying block.

Continue laying the first two courses of the straight section this way until you reach the starting point of the curve. The ends of the last block in the second course must align with the start of the curve at 90 degrees, parallel to the wall. Remove the last block in the second course and slide the preceding two blocks over by one block toward the left if you need to correct this.

Rotate the block removed from the second course and place it against the last block in the first course with the short side facing inward to start the curve. Reverse another block and insert it into the gap left while shifting the two blocks over on the second course.

Place a stone mason’s chisel into the notches on top of a special double center-split block and deliver one or two heavy blows to the end of the chisel with a heavy hammer. Turn the block over and chisel the two underside notches the same way; this will split the block neatly in two.

Place the split side of the block against the end of the last block in the second course; save the other split half for the end of the curve on the second course.

Build the first two courses in the radius by setting the short side of the blocks facing inward to follow the curve.

Place the split end of the second half of the chiseled block against the last block in the second course when you reach the end of the curve; this will align the end parallel with the forthcoming straight section. Lay the next block on the first course with the short side facing outward to transition the radius back to a straight line.

Lay the rest of the blocks in the first two courses along the final straight section by alternating the block as described in Steps 2 through 4.

Lay the third and subsequent courses by repeating the entire procedure. Start and end the curve on the third course with a chiseled half block centered over the joint in the underlying chiseled block, and repeat this procedure on subsequent courses.

Finish the wall by placing the groove on the underside of the end caps over the raised center-hole lips of the final course. Alternate the front and back edges of the wedge shaped end caps along the straight sections to keep them parallel. Transition into the curve by rotating the cap at the start and end of the curve and follow the radius by positioning the short side of the end caps inward.

For added stability, join the end caps to the top of the wall by placing a bead of silicone adhesive with a caulking gun on the top edges of the wall, and along the mating sides of the end caps while laying them.