Build an asphalt covered basketball court in your backyard by first sectioning off the space that you will be using. The dimensions are completely up to you, however, to give enough room for a standard high school half-court you will need a 30 by 30 foot area. Place stakes in the ground to mark the four corners of the court. Remeasure the distance between the stakes to make sure your dimensions are correct. Double check to verify that your dimensions are squared off by making sure you have the same distance from the top left stake to the bottom right stake, and from the bottom left stake to the top right stake.
Dig up the area inside you laid out. Remove any large pieces of rock, as these will eventually create uneven areas on your finished court. Excavate 7 to 9 inches deep to allow room for the crushed rock and asphalt that you will need to lay. Level out the area after all the necessary dirt and rocks have been removed.
Dump and level out 4 to 6 inches of gravel to cover the dimensions of your court. This will be the base the asphalt will be spread over. Compact the rocks by walking over then entire area or rolling a weighted compaction tool around the entire area. Make sure there are no depressions or uneven spots before moving on to the asphalt.
Spread 2 to 3 inches of asphalt over the gravel to act as the blacktop for your basketball court. You can hire a professional to lay the asphalt for you, or you can do this job yourself by wheel-barreling in sections of asphalt at a time. Level out the asphalt so that it is even throughout the entire court. Compact the asphalt cover in the same manner as you compacted the gravel. Make sure the asphalt is level after it is compacted and allow it to dry fully. Come back the next day to make sure that the asphalt is completely level and does not need to be adjusted anywhere before moving on to painting the basketball court's lines.
Purchase a basketball court stencil to give you a guide to paint the lines on your court. You can purchase a stencil from the "Basketball-Court" website. It will come with step-by-step instructions to guide your through the stenciling process.
Add the basketball hoop to your court. You can purchase a portable unit that does not need to be cemented in, or you can purchase an in-ground basketball goal that will remain in place. Most sporting good stores offer in-home installation with the purchase of in-ground basketball hoops. Make sure the backboard is 3 feet in front of the baseline and the front of the rim is 15 feet from the free throw line to make the lines on the court correct.