DIY Cement Block Wall

Snap a chalk line where you intend to install the cement block wall. Mark the line with a grease crayon as well, because the chalk may disappear as you work around it.

Set the blocks in position along the chalk line as a dry run. Put corner blocks in position on each end. Use scraps of 3/8-inch plywood between blocks as spacers. When you have the spacing the way you want it, mark the location of the corners. Set the blocks aside.

Mix mortar following package directions. Only add enough water to make a stiff consistency.

Use a trowel to spread the mortar 1 inch deep and about 3 feet from one of the corners. Set the corner block with the finished end toward the outside of the wall. Press it firmly into the mortar. Use a level to ensure the block is level and plumb, or straight up and down, on all sides.

Spread mortar on the end of the next block to create a 3/8-inch joint. Set it in place. Continue placing mortar and blocks in this manner on the concrete foundation until you reach the end of the first row, or course. Check the blocks as you set them for level and plumb. Make all alignment corrections before the mortar begins to set.

Cut blocks, as necessary, by scoring a line on the block where you plan to cut it with a sharp object, such as a spike. Place a masonry chisel along the line. Tap the chisel with a hammer to break it. Repeat the process on the other side of the block.

Place another corner block to begin the second course. Stagger blocks with the blocks from the first course as you lay the second course. Continue until you reach the top of the wall.

Pull a jointer tool along each of the joints to create a uniform appearance before the mortar dries. Dip the jointer in water as you work to make this task easier.