My dad and I made the frame for the baseboard. Made from 8 1.8m x 32mm x 19mm wood, cut to my design, and screwed together. The 2x 30cm ends are bolted to the main frame, so can be removed for future expansion. To add more rigidity a 6mm MDF board will be screwed on top.
All in all to get it to this stage it took about 3hours.