How to Build a Block Wall Boundary Line

Find the parcel measurements for your home at your county's courthouse. If you feel comfortable determining the measurements on your property, do so and mark the property corners using wooden stakes. Otherwise, hire a professional surveying company to mark the corners of your property.

Tie the end of a string around one of the property corner stakes, and wrap the string around the perimeter of the other stakes, securing it to the last stake. If you want to build a wall on only one side of your property, simply stretch the string in a straight line from one stake to the other stake on that side of the property.

Place a level on top of the string to ensure the instrument's air bubble centers, which means the string is level. If needed, raise or lower one end of the string until the string is perfectly level.

Dig out the soil directly beside the string on your side of the boundary line. Create a trench that is 4 to 6 inches deep and at least 24 to 28 inches wide. Place the removed soil in a wheelbarrow, and transport it elsewhere. Use the level to ensure the bottom of the trench is even; remove additional soil as needed until the trench's bottom is level.

Pour 4 to 6 inches of crushed rock, which is base material, into the length of the trench. Hit the top of the rock firmly and repeatedly with a hand tamper to compact it in the space. When properly compacted, the height of the rock will compress by 1 inch.

Spread 1 inch of sand on top of the crushed rocks. Spread the sand to make it level, and then compress it firmly with the hand tamper

Lay the first row of concrete blocks end to end along the entire length of the trench. Place each block as close as possible to the other blocks, leaving no gaps. As you install them, lay a level across their tops, and tap them with a hammer until the tops are even.

Insert a metal locking pin through the holes in the top of the concrete blocks, and hammer them into the ground until they are flush with the top surface of the blocks.

Cut the length of one concrete block by 4 inches using a hammer and chisel. Set the block on top of the first row of blocks to start the second row. Lay additional blocks directly beside the first block all the way down the wall. Cutting the first block offsets the joints of the second row of blocks from the joints of blocks in the first row.

Install metal locking pins through the top holes of the second row of blocks just as you did with the first row's blocks.

Install the concrete blocks in rows until you achieve the desired height for the wall. Fill in gaps along the side of the wall with gravel to provide support.