This work reports on the characterization of a neutron beam shaping assembly prototype and on the first steps in the design of a treatment room for BNCT that are carried out as part of the program for the development and construction of a Tandem Electrostatic Quadrupole Accelerator devoted to Accelerator-Based Boron Neutron Capture Therapy in Buenos Aires, Argentina. The beam shaping assembly has been characterized by means of Monte Carlo simulations (MCNP) and measurements have been performed on an experimental line of the Tandar accelerator at CNEA (National Atomic Energy Commission of Argentina). The neutron flux was generated via the ⁷Li(pn)⁷Be reaction by bombarding a thick LiF target with a low current 2.3 MeV proton beam and it was measured by means of activation foils. The measured and calculated parameters comply with those suggested by IAEA when scaled to the final proton beam current of 30 mA. The treatment room design is conducted by means of MCNP simulations.