- I am trying to remove a bow in hardwood floorboards.
- Under the bowed floorboards are two hardwood bearers (about 3m span) on masonry piers.
- Both bearers had about a 20mm sag at midspan.
- I jacked both bearers up to straighten them and left them propped for a few months.
- I then jacked the bearer another ~7mm to overcompensate.
- I sat a 150 PFC on the piers for one bearer and bolted it tight against the bearer using five M12 bolts.
- The joists are not sitting on the PFC.
- When I removed the jack, the bearer dropped back: the centre sagged at least 12 mm immediately.
- Floor level readings changed: above the piers it rose about 2 mm and 5 mm, and a nearby point on a joist supported by that bearer dropped about 5 mm.
- There is still a ~20mm sag in the floorboards.
- We need to install and level base cabinets for a stone benchtop (templating in a few days, install in about two weeks).
- The kitchen runs against an exterior wall, single brick vaneer house.
- The start of the kitchen run sits over the area that dropped 5mm, and the kitchen levelling needs to stay stable.
Do I either:
- (a) Leave the PFC/bearer as it is and accept the remaining sag, then install the kitchen level to a laser line, or
- (b) Jack and hold the bearer up again before installing the kitchen, and if so, what is the correct permanent way to make the bearer or the PFC hold that corrected level so it does not drop again?