Here is a pictorial about how we upgraded Lompoc HS, California's old Vaulting pit by adding three base unit sections, and a common top cover to it from Paso Robles HS.
Here is Paso Robles old Port-A-Pit with slanted front bun sections and a decent top pad. We loaded it on my trailer after they got a new pad which conformed with the new HS rules.
When we got to Lompoc we chose to reset the planting box. The run-way had a slight downgrade on the end which made the existing box position too low. In order to do this we had to flatten the front edge so that it would lay on the top of the runway it self.
Next we set the planting box in proper position making sure that it was level with the top of the run-way. In addition, we back-filled with a mixture of dirt and long jump pit sand around the edges of the box so that ground was smooth and flush with the top of the box.
Then we cut a 4'x 4' piece of old wrestling pad they had in storage and then used the top of the box as a template and cut a opening so that it fit perfectly around the box.
Then we placed the front bun sections in place around the box with the collar in place.
Since the blue Lompoc pit sections and the red Paso Robles pit sections were not the same heights, we elected to place tires under the red sections so that they were the same height as the blue.
Next we positioned 4 base unit sections across the back of the front buns and tied them all together with cloths line. On any available o-ring.
Then we attached both the old blue Lompoc top pad and the red Paso Robles top pad and tied them to all available o-rings. Please note that it is important to not tied them too tightly but rather leave just a little bit of slack so that they don't rip the grommets out of the fabric.
Next we installed a new gray single ply 20'3 x 19'8 common top cover over everything and fastened it with cloths line to any and all available clips and o-rings. So the result is a landing pad up to the new minimum HS standards with 2' of additional padding on each side and 4' of additional padding behind the rear of the pit
Then we set the standards up with their existing standard base padding and admired our work.
Total cost: $750