Build an outdoor fire pit using cast concrete stones and sand. Build the pit on bare ground or concrete, but not on a wooden deck. Check local regulations and homeowner organization rules before beginning construction.
Begin the project by clearing a circle on the ground where you plan to build the fire pit. The soil under the pit should be level. If you are building using bricks or rocks instead of the formed concrete, you may need to install a concrete footing to support the structure.
Drive a round stake into the center of the clearing, and tie a string around it to create a compass. Use the compass to draw a round circle the diameter of the pit. Use ground-marking paint to highlight the circle.
Lay the first course of concrete stones around the circle. Use a carpenter's level to ensure the course is level. Add a second layer of stones so the joints offset from the first layer. Continue adding stones until you reach the desired level, finishing with a course of capstones.
Add sand to the bottom of the fire pit. The sand raises the level of the wood so the flames are more visible. Consider adding a screen to prevent flying embers.