How to Build a Halfpipe

In this Instructable, I will be showing you how we made a halfpipe ramp for scooter and skateboarding fun. When I started this Instructable we had already completed the ramp – see the stop-motion video that we created, which shows the majority of the build.

This project is extremely fun and surprisingly not at all time consuming, we managed to get the job done in roughly 3 days. It was a brilliant project and kept the whole family happy, healthy and fit during lockdown!

1. Sheets of plywood: enough thin 6mm plywood (ideally birch, which is less prone to splinters than normal plywood) to cover the area of the ramp that you ride on, multiplied by three (so you have three layers), as well as several sheets of thicker 12mm plywood to form the structural curves
2. Other wood: enough 6 x 2in (150 x 45mm) beams to construct the frame
3. Lots of screws: 40mm long for the thin plywood, 80mm screws for joining wooden beams
4. Scaffolding poles

First, decide on the size of your ramp, including its height. Decide how long the curved sections of the ramp will be, bearing in mind that you need a flat section in the centre.

To build the frame you will need lots of large beams. Firstly, cut 3 beams that are as long as your ramp. Lay two beams on the ground, parallel to each other, and at a distance apart equal to the width that your ramp will be. Lay the third beam in the middle of the first two. Saw two end beams that fit along the ends of the three beams, in order to make a rectangle shape. Screw all these beams together to make a frame. For the cross beams, you need to measure the gap between the long beams. Cut several beams to this length. To calculate how many beams you will need, divide the length of your ramp's flat section by 25cm and round to the nearest whole number. Multiply this number by two for the two sections (either side of the middle beam). Attach the cross beams on both sections of the frame, at roughly 25cm intervals, as depicted in the photo.

The next step is creating the curve of the ramp, which is made from thick plywood for strength. Firstly, draw the curve onto your sheet of thick plywood. We did this by attaching a pencil to a piece of string, which was approximately 5 feet long as this was the ideal radius for the transition of the ramp. Hammer a nail into the plywood at the centre point of your curve and tie the other end of the string to the nail. Pull the string taut and draw your curve. We chose to have one side of the ramp higher than the other for different abilities. You will need a curved piece for every 4-foot section of your ramp (e.g. for a ramp that is 8 feet wide, you would need 6 curved pieces – one at either end and one in the middle at each end of the ramp). Screw the four edge pieces onto the outside of the frame, so they stand up vertically.

The next step is to make the rungs that go up the curves. Above is an image of roughly what it should look like. First, you should mark your remaining curved pieces (in our case, we had two pieces) to show where your beams are going to go. It is best to place them at regular intervals to make drilling the plywood on top easier. We spaced the beams every 25cm. We used long beams to span the entire width of our ramp so, next, use a jigsaw to cut slots out of the pieces of curved plywood. The slots should match the profile of the long cross beams so that the cross beams can be slotted into the plywood. Fit the cross beams into place on top of the middle of the frame so that the bottom of the slots lines up with the top of the curved edge pieces. Screw them into place securely.

This step is by far the trickiest and it is advisable to have more than one person on the job as it is helpful for someone to hold the plywood in place whilst you screw. The concept however is simple – screw one layer of thin plywood onto the beams. Follow that with a second and third layer of plywood, making sure that your seams are in different places on each layer. Finish the edges of the ramp with more plywood, cut to match the shape of your ramp.

Tip: On the sides of the ramp, mark the positions of all the rungs so that you know where to screw. Then position a plank of wood between two marks on either side of the ramp and use it as a guide so you can screw into the plywood along the edge of the plank.

For our coping we used some old scaffold poles we quite literally found lying by the side of the ramp in the undergrowth nearby. We then used the method depicted in the photo to attach it to the top of the ramps.

All you need now is a platform or two to stand on at the top of the ramps. To do this you will need to construct a frame using beams. Decide on the width of your platform (ours was 50cm) and cut a beam to this length. Measure the height of your ramp and cut another beam to this length. Attach the two beams together at right angles to each other and then screw the shorter beam to the underside of the ramp, with the other beam resting on the ground as a support. Repeat at intervals along the ramp. Next, screw on a sheet of the thicker plywood to create a platform at the top of your ramp.

At the end of this project, we made barriers at the back of the platform, for safety. To do this we used some more old scaffolding poles (or you could just use some planks of wood) to go up vertically to support the barrier. Simply attach one pole or plank at each corner at the back of the platform, then screw planks of wood between the poles on each side.