VERTRAMPS The two photos contain diagrams and an outline for building yourself a solid halfpipe ramp for full-on vertical skating, which many swear is the ultimate proving ground for skaters of all time. The dimensions (24′ wide, 16′ of flat bottom, 9’6″ transition with 1’6″ of vertical wall) are commonly used for several reasons: they reflect the fact that plywood is widely available in 4×8′ sheets, and 2×4 and 2×6 studs are usually bought in 8′ and 16′ lengths. Using lumber with these standard dimensions will add up to a nice 24-footer without wasting cut-off ends and creating a lot of useless scraps. If you lack funds or material, you can always cut back on your needs by building a smaller ramp, or by making the whole thing portable so you don’t need a foundation. Just remember: cheap is cheap. So, if you’ve got the money and the materials, build it big and strong without cutting corners. It will pay off in the long run.
FOUNDATION Once you find a site to build on, it is important to make sure it is close to level. A level bottom framework makes everything else fall into place easier. If you are building on an incline, dirt, or uneven ground, you might want to elevate your frame on posts. To do this, sink 4×4 redwood or pressure treated posts at least two feet into the ground and leave them sticking up high enough at the low end to run a level horizontal beam between them. If you want to build a super-sturdy foundation, lay the bottom framework on top of posts sunk in wider post-holes that are filled with cement (see page 10, figure 1). Posting also lifts the structure off the ground, thereby keeping rot and insect damage in check for a longer period. Besides protecting your ramp, it is required in some areas that permanent wooden structures be raised above the ground. If you are building on hard, flat ground, cement, or asphalt, an easier, cheaper and less permanent way to build your foundation is to lay your 2×4 framework on the ground and level with shims of scrap plywood. Whichever of these three bottom framework variations you have, be sure to thoroughly check it with a level before you continue; a slight tilt at this point can easily screw things up in the end. This part of the ramp will be mostly covered up, so make sure that it is solid before you move on to the next step. Use 2×6 beams and joists. Lay these in a rectangular box the size of the ramp. In our case it would be 16′ of flatbottom plus two 9’6″ radius transitions and two 4′ rollout decks. Your framework will be 43′ long and 24′ wide. Brace this structure with 2×4’s spaced 12″ apart (on center; see glossary) under the flat section. Traditional let-in bracing should be used here; ask a carpenter how it should be done. Place the 2×4 joists in the frame with the 2″ side facing up and sitting flush with the top of the 2×4 beams. Secure the joists with two 16dd nails in each end, or two equivalently-sized screws whichever you prefer. The joists will act as a solid base for connecting the plywood to the flatbottom section.
Thanxs for the info Thrasher