Measure the space of the room or area in which you want to build the portable ballet floor and calculate the area of the floor by multiplying the width and length of the space.
Calculate the maximum number of 4-by-8-foot MDF panels -- the standard size in which panels are sold -- to fit inside the area. Use this number of panels to complete the project. For example, six panels will make a 12-by-16-foot floor.
Install a spring system before installing the fiber board, to make the floor better suited for jumps and leaps without strain on the joints. Apply 3-by-3-inch double-sided adhesive foam pieces to the floor, leaving six inches between each piece in all directions.
Measure along the sides of panels to mark where biscuits will be inserted to join the panels together. Space the biscuits about 8 inches apart. Note that not all panels will be aligned on four edges; corner panels will only be joined with other panels on two sides, and border panels on three sides.
On a sturdy work table, cut slots for the biscuits on points marked using a biscuit joiner or a router with a 5/32-inch slot. Cut slots that are approximately one-half longer than the biscuits for an easy fit. Do this for all the edges of panels to be joined.
Move all the panels to the prepared dance floor to join together with biscuits. Apply wood glue to the biscuits and to the straight edges of panels. Line the edges of two panels so that they are flush and clamp together.
Lay the fiberboard panels on top of the foam pieces as you join them. Press down to firmly to prevent bumps or unevenness in the flooring.
Thoroughly sweep the floor to remove dust and dirt from transport and installation. Wax the floor, ideally with a wax floor treatment specifically designed for dance floors. Use wax sparingly, as ballet floors, unlike other types of dance floors, should not be too slick.