A
Anonymous
Guest
Many thanks for the technical advice, as advised the supporting joists are ancient 4X4 oak. Seven of these span 13'. All the advice I'm getting indicates the joists should never have sagged so dramatically, maybe the room was used for heavy storage when the oak was still green. As there is no indication of recent movement I plan to shape new joists to the bowed floor,then put down new boards to tension and flatten. Thanks again.