How to Make a Block Wall Footer Using Blocks

Refer to the manufacturer’s instructions for the particular type of block you're using to determine how much of the block the manufacturer recommends sinking into the ground as part of the footer. This will be the base layer for the wall. Commonly, most manufacturers recommend at least half the thickness of a block be set below ground level.

Measure for your footing trench. The width should be half the height of the wall, so if the wall is 4 feet high, the footer should be 2 feet wide. Dig at least 6 inches deep for the gravel, 2 inches for the sand, whatever the manufacturer recommendations for the first row of blocks and at least 1 inch for the base layer of mortar. The footer should be centered beneath the wall to spread the weight out evenly.

Shovel the gravel into the trench so that the bottom is layered by a couple of inches. Tamp it into place. Tamp another layer in place. Continue until you have at least 6 inches of compacted gravel. Then do the same with the sand until you have at least 2 inches of compacted sand.

Mix up some concrete mix. Shovel at least 1 inch of concrete mix, or "mud," on top of the sand.

Layer the footer blocks on top of the mortar mix, with at least 1/2 inch of space between them. Use the mason trowel to fill the gaps between the blocks with mortar. Tap the blocks together slightly so the mortar bonds to the sides of each block. Insert as many rows of blocks as your footer width requires.

Set the level on top of the layer of footer blocks. Tap them down into the base layer of mortar with the rubber mallet. Use the level to ensure that the first row is completely level across the base of sand and concrete. This is the base for the entire wall, so it needs to be completely level. Let the concrete dry 72 hours before setting the wall.