How to Build a Halfpipe
When nearby landmarks aren’t steep enough, it’s time to build your own halfpipe. Think about getting all your friends to help.
Required Materials
- 8 sheets ¾” plywood
- 2×4” stock
- 10’ PVC pipe
- laminate
- nails
- 1 ½” screws
Required Tools
- hammer
- circular saw
- drill with selection of bits
- tape measure
- fishing line
- pencil/paper
Instructions
- Site and Layout - Find the site that you are thinking about using and determine the overall size of your halfpipe. Think about the standard sizes of lumber and plywood when deciding on size.
- Layout - Begin by laying out the framing system. There will be two symmetrical sides. Construct a bracing structure approximately 4’ wide and 8’ long from 2×4” stock. The base should be in two sections 4×8’ with floor joists spaced approximately 7 7/8” apart. Next, lay the vertical and horizontal side bracing on its side. The height should be approximately 3’ 3”. There should be three pieces in total. Use the fishing line to lay out a curve with a 5’ 7 1/2” radius. This will be the bowl of your halfpipe. Then construct the side bracing with the radius line dictating support areas. The bottom supports should double up with the base and vertical support systems.
- Cross Members - Connect the two vertical support sides with cross members. These should be placed approximately 7 ½” apart. It is important to double up the cross members where the plywood seams will meet so the plywood won’t separate when in use.
- Decking - Attach plywood decking with 3” screws. For the ramp and starting platform, double up on the decking. On the ramp itself, glue a smoother surface to the plywood for a better ride. The starting platform should be supported by joists to hold several people at once.
- The Transition Cushion – The place where the horizontal starting platform and the vertical decking meet is called the grinding rail. In this particular section of the halfpipe, an element needs to be introduced to minimize damage to both the horizontal board and the vertical decking. Install a section of blocking along the transition section. Take a 10’ length of PVC piping and screw it to the support system and the plywood. One screw every 8” will do the job. Ultimately, this will provide a “cushion” to the transition area.
- Disassembly – Ideally, you would be able to use the halfpipe year round. In most places, this is not possible. As you build the halfpipe, keep in mind that you will likely have to disassemble it for the off season. Consider where the best disassembly points are for your storage requirements. The base system will probably yield the largest sections at 4×8”. The ramp itself will need adequate storage space. Just keep in mind that screws come out a heck of a lot faster and easier than nails.
Tips and Warnings
- You might want to think about covering the halfpipe when not in use to protect it from rain and wear.
- Check the stability of the halfpipe frequently and replace any rotting boards as soon as possible to prevent injury.