Hoping for good advice from the forum's eminent expertise again. This time too, it's about floor joists and dimensions. After good advice on how to handle the floor joists in the 70s part of the house, it's now a super sturdy floor there. Now I'm focused on the part of the house that was built in 1930. The floor is opened up and what I see are wooden beams 65x160 with approximately 60 cm centers, length 3.9 meters. No noggins anywhere, but iron rods downward about 2 meters into the length of some beams (maybe all), which are cast diagonally in the traditional way in the basement ceiling vault. The beams are straight and nice, not a single one has twisted. The width of the entire room is 4.7 meters. The particle board floor laid in the mid-70s was sparsely nailed, glued at joints but not to the beams. It has creaked, but of all the floors in the house, this one has been the least creaky. We've not felt that the floor has flexed and the nails in the particle boards show no signs of the floor flexing.
What is the expertise's advice on the beams? Can I continue to rely on these and have a stable floor, or should I reinforce it?
What is the expertise's advice on the beams? Can I continue to rely on these and have a stable floor, or should I reinforce it?
Dimensional measurements from this time were always set in inches. A very common dimension for floor joists was 3x7 inches, which can be translated to 75x175 mm. 65x160 might be 21/2x61/2 inches, 62.5x162.5 mm. In any case: 65x160 mm cannot handle a span of 3.9 m without significant deflection issues. However, if each beam is supported by a steel beam, then the situation is entirely different. There are no problems whatsoever.
Thank you for the response. It made me dig into all the details and found that all the beams are supported underneath by two rails evenly spaced. This means that each floor beam is supported at each end and then supported at approximately 1.25-meter intervals. This should be okay if I understand JustusAndersson correctly. What I will do is add noggins where you enter the room and then noggins where the beams are supported. Then it's a solid construction upgraded for the long term.