So you decided to install an in ground trampoline?
The in ground trampoline usually sits just above a pit that is 27 to 29 inches deep. To do this, you need to excavate a pit of 13.6 feet in diameter on the top of the trampoline that sits above the ground and 12.6 feet in diameter for the lowest part of the pit. If the ground trampoline must be assembled in the pit areal, then the pit diameter should be 14.6 feet on top and 13.6 feet on the bottom. Before beginning the excavation, it is best to consult a landscaping expert for their recommendations on local soil conditions and the proper measures needed for drainage in the local area.
The entire in ground trampoline system will be 33 inches high to allow for the trampoline to be four to six inches above the grade. If the area requires extra measures for good drainage it may be beneficial to add 4 to 6 inches of gravel to the bottom of the pit for good drainage and prevention of standing water. If the area is particularly damp, a sump pump may be needed as well. This is a question for the local landscaping expert regarding local soil conditions and drainage. The site surrounding the ground trampoline should have a minimum of 18 feet overhead clearance and nothing surrounding the area for 6 feet around. The ground should be soft with impact promoting grass, sand, wood shavings or other forgiving material.
Before you begin digging for the foundation for the ground trampoline, collect and organize all the included hardware and parts for the in ground trampoline. These parts typically include the following: top frame segments, bottom frame segments, side panels, rubber edge protector strips, pad set, jumping surface, springs, bolts, nuts, washers, screws and a tool kit. After you have done that, set the panels out in a large circle. The template provided for the lower frame will aid in marking the pit for excavation. Make sure the spring holes on the top frame are facing up. Attach bolts and screws but only loosely to allow for movement of the system during assembly and bolt alignment. Using a long screwdriver to enable hole alignment is recommended. Assemble the lower ring again leaving screws loosely fastened. Overlap 3 panels on the ground upon each other to align holes.
Attach top holes to panel holes and to upper frame with bolt and washers on the panel side, nut and washer on frame side, keeping spring holes facing upward on top frame, again loosely tightened. Attach upper and lower frame rings using proper bolts and washers and nuts and washers, leaving all loosely fastened. Attach one panel at a time from lower bolts to upper with an Allen wrench. Continue until complete then tighten all bolts. Place frame in pit and back fill soil to make ridge rising up to edge of apparatus. Install the side springs. There will be frame and mat holes for each spring. Carefully check the pattern to see that each spring is connected. Install the Edge protector pad making sure all connections are complete. Do safety checks and enjoy the in ground trampoline.