How to Do Concrete Blockwork

Ensure that your concrete blockwork has a stable foundation. Build a framework of 2-inch by 6-inch boards that extends two inches on all sides than the size of your intended wall. Your wall must have a 2-inch wide lip on all sides to ensure that it has a good, stable base. Secure the framework by pounding wooden stakes at 4-foot intervals around the perimeter of the framework and nailing them to the form boards with double-headed nails. Simply nail the double-headed nails into the stake while it is pressed against the form board. When the nail reaches the lower head, stop hammering. This ensures that you are able to remove the nail later when you dismantle the form boards.

Fill the form boards with concrete. The amount of concrete you need will depend upon the scope of your project. A single cubic yard of concrete typically covers 81 square feet of space, at four inches deep. Drag another 2-inch by 6-inch board across the top of the form boards to knock down the high spots and fill in any low areas in the foundation. Allow the concrete to cure for at least 12 hours before continuing.

Mark the exact corner locations of the wall at each end. Pull a chalk line from one end of the wall to the other to create a straight line between the two ends. Trace the chalk line with a grease pencil so it doesn't fade or get wiped away while you are working.

Mix a batch of mortar by combining one part masonry cement with three parts sand in a five-gallon bucket. The size of the project will determine the amount of masonry sand and cement required for the project. Mix the ingredients in this ratio: one part masonry cement and three parts sand. You could use a shovel to measure, or a bucket, as long as the measurements remain the same. Mix these ingredients around with a hoe and create a pit in the center of the bucket. Slowly add up to 2 gallons of water, mixing constantly with the hoe, until the mixture is the consistency of mud and you can form a soft ball with your hands.

Spread a 1-inch thick layer of mortar inside the grease marks for the concrete blockwork wall, using a steel trowel. By placing the point of the trowel on the concrete base and pulling the trowel toward you in a side to side motion, the mortar will slide off of the trowel in a straight line. Spread it out to fill in the grease lines, and cover enough space to lay three or four blocks.

Place the first block into position and tap the top of the block lightly with your hand to embed it in the mortar. Spread a 3/8-inch thick layer of mortar on the end of the block and set the second block into place, gently pushing it against the first block to create a firm bond between the two. Continue laying the blocks in this manner.

Position the next layer of blocks so the end of one block is at the center mark of the block below it. This staggering effect ensures the wall will not have any weak joints. Always use 1-inch thick layers of mortar between the layers of blocks, as it will compress slightly, giving the appearance of only being 3/8-inch thick, like the upright joints. Allow the mortar to cure for three to seven days before allowing the blockwork to get wet. Typically, you can build a block wall up to 6 feet high before requiring additional supports. However, check with your local building inspector before building a wall over three foot high. A single layer of blocks equals 1 foot in height.