Note 174 — Chapter VI · THE KEEP OF THE NORMAN CASTLE

Such cross-walls, found in the larger towers, were not merely useful as partitions between the rooms. They enabled the builders to lay their floors more conveniently, as timber of sufficient scantling for so large an undivided space was obtainable with difficulty. In case of the great tower being taken by storm, the cross-wall on each floor formed a barrier to the besiegers, shutting off the tower as it did into two halves. This is well seen, for example, at Porchester.