You need to select a levelled piece of ground for making the barbecue pit. An averaged sized cinder block pit is about 40-by-56 inches big but you can alter the dimensions according to your needs and the space available. Take a measuring tape and mark the dimensions on the ground. Outline the rectangle with spray paint.
Take a shovel and start the digging work. Begin inside the paint line marker out the rectangle and dig at least 8 inches. This shall become the foundation of your grill and hence, you have to make the dig area perfectly levelled.
Put a layer of gravel inside the rectangular pit and make sure it is 2 inches thick. You have to pour mortar around the inside boundary of the pit and level it with a trowel when it is still wet. Ensure you lay down 2 inches thick and 1 foot wide layer of mortar.
While the mortar is still wet, lay down the first row of cinder blocks upon it. Make sure to level each block you place and cover the entire perimeter of the rectangular pit.
Keeps the holes on the cinder blocks facing upwards vertically and then fill them up with dirt. This dirt will act as an insulator in the pit and sustain heat within it.
Apply a one-inch thick layer of mortar on the blocks before laying down the second row of bricks in the same manner. Repeat the process once again to lay down the third and final row of cinder blocks inside your barbecue pit.
Apply another layer of mortar on the third row of block and sink the metal braces into it. These braces will be used to hold the metal grate. Lay another row of blocks after that.
Conclude your task by placing the metal grate on the braces and let the pit dry for at least 24 hours.