The new main beam for the stone floor was installed and the ground floor was concreted . The stone floor was reconstructed , reusing the old stone bearers and those joists that were fit for reuse . Other joists were made new from oak or pitch pine . New floorboards were laid in the dust floor , the 1 1 ⁄ 4 inches ( 32 mm ) thick elm boards being double @-@ grooved with a metal tongue between them . Those on the bin floor are of a similar configuration . The top four courses of brickwork of the mill tower were removed and work began on rebuilding them , aided by a trammel attached to the upright shaft .