The millstones were removed from the stone floor , which was then repaired . One of the main beams was found to have been attacked by Death Watch beetles , and over a third of the elm beam was replaced with oak . The six supports for the hurst frame were repaired one at a time , as they bore the whole of the weight of the machinery above . One post required replacement . It had rotted and the floor had sunk by 4 inches ( 100 mm ) causing the second main floor beam to fracture . When this work had been completed , the stone floor was removed , including the second main floor beam , which was removed in one piece so that the most suitable route to install its replacement could be assessed .