Marking Off Your Slab

• Decide where you want your concrete slab to go and exactly how large you want it to be. Use spray paint or powdered chalk to mark the area, spraying directly onto the grass or dirt that your concrete slab will cover. If the area is covered with grass, you will get better results if you take a shovel and dig down an inch or two in order to remove the grass and roots in the area where the concrete will be. You may wish to use a spade to divide the grass in the area into strips so that you can remove it as sod, placing it onto loose soil elsewhere in your yard in order to transplant it.
  
  

Building a Mold

• Once you have marked the area and removed any excess grass and the topsoil that it was attached to, it's time to build a mold for your concrete slab. Use straight, smooth boards along the perimeter of your marked area, using screws to hold them together so that the mold can be easily disassembled once the concrete has set. Use a level to make sure that the top of the slab won't be crooked, digging out the ground underneath portions of the mold as needed. When you are finished, you should have a square or rectangular wooden frame along the edges of your marked area, buried slightly into the dirt, and held together by screws at the corners and wherever two boards meet.
  
  

Pouring the Concrete

• Fill the bottom of your mold with gravel and other rocks before you begin pouring your concrete. This will not only let you use up any rocks and gravel that you might have around your house, but will also help you to use slightly less concrete when making your slab. Mix the concrete according to package directions, then pour it into your mold on top of any rocks or gravel that you placed inside of it. Fill the mold until the concrete is even with the top of it, smoothing it to create a level surface.
  Allow the concrete to set, placing any decorative gravel or other decorations into the top layer once it has started to firm slightly. Leave the mold in place until the concrete is completely dry, then remove it by first taking out the screws and then pulling the individual boards free. Fill in the depressions left in the dirt by the boards with soil. You can either sow grass seed into this soil so that the grass will grow next to the slab or you can use decorative fencing to mark off the slab's edges.