We investigated the thermal expansion behaviour of pure-silica zeolite frameworks FAU, CHA, LTA and SOD through a series of NPT simulations ranging from 20 to 1000 K. We note that volume fluctuations during the MD increases with the temperature, making the results less reliable in the higher end of the temperature range. The thermal expansion curves and computed thermal expansion coefficient are reported respectively in Figure and Table and we now discuss them individually against the known experimental data.