YouTube personality The How to Dad shows how to build a stowable half-pipe for budding BMX racers or skaters from his Ontario garage.br br "This video will show you how to easily build a mini-ramp using common materials available at any lumberyard and a few tools. You have space for a mini-ramp, don't let anyone say you don't!" he explains in this easy-to-follow tutorial.br br It took just four hours to build the half-pipe, he explains.