3 rooms of my home have 2"x10" floor joists, 16" oc, 16' span. There are no supports beneath & the floor bounces quite a lot.
Is adding a beam underneath my best option to strengthen the floor?
There is roughly 12" from the bottom of the joists to the ground (in the crawl space) & there is no proper access, just numerous service holes cut into the floor & then later patched. Also, the subfloor (which currently is the only flooring in 2 rooms) is solid wood tongue and groove planks.
I considered pulling up some of the flooring to gain access. However, the house shell was constructed & lath added, etc, prior to the 2 interior walls being added. The walls are nailed to the subfloor, though the subfloor was never nailed to the joists). The walls run parallel to the joists and are placed between 2 joists.
The ceiling is closer to 2"x6", 16" oc, 16' span. I say *closer* because the wood in the attic still has bark on one side of the board(s) & varies from board to board. (Beneath a very thin layer of cellulose insulation is a VERY old layer of straw insulation & beneath that is a layer of soot.)
The ceiling in the rooms below flexes, sometimes A LOT depending upon the weight of the person moving about. The plaster ceilings below have cracked as a result of all the movement.
How do I fix the flex in the ceilings so that I can repair the plaster & not have it re-damaged later?