I am planning to install an I-beam under the ceiling (on the lower floor) to raise the load-bearing layer by 30-40 mm. It is weak in the middle of the future floor, the span is 6.5 m on the load-bearing layer and 800 mm between the joists. The beam will be placed in the middle between the joists, i.e., 3.25 m on each side. This is a log house with two load-bearing walls plus a core wall, typical of a Norrbotten farmhouse. Does anyone have ideas on the dimension of the beam? The length of the beam is 4.6 m.
