Hello! Loyal reader but not very active in writing here on the forum! But here comes an attempt, have to start somewhere 
I have an almost square house measuring 11*9m with a center wall on the ground floor. This center wall is to be removed to make the workshop more usable and the loft above more stable in the floor structure. The center wall consists of wooden posts about 100*100mm thick, these vary, between which some kind of stone/brick has been built in the cavities, the posts are currently about 1.5 - 2 meters apart, an old building built surely a bit on HO.
The function of the center wall is to support the floor joist above, the house body is on stone up to about 3m after which a wooden sill has been laid on which the rafters rest, "I can imagine a barn looks similar to this."
So the floor joist rests on the stone wall and on the center wall. The span is 9 meters and the center wall is in the middle.
Hope you get a good picture of the current situation. The floor joist is quite slender, 7'20 cm on the beams and C/C 100-120 span 4.5m.
I intend to help the floor joist by replacing the center wall with a type HEB180 or alternatively HEA200, with 3 support points, I would prefer not to have 4, the span is about 11 meters. My idea is to aim for 3 with a larger dim on the beam, rather than 4 with slimmer ones. But there are limits this should be handled with of course.
In addition to this, I plan to help the old floor joist with 2 additional beams so that the span doesn't become 4.5m in depth. I will do this with 2 IPE180 with 3 support points, thus reducing the distance to 2.25.
Thus, my question is what kind of beam do I need to be on the safe side to avoid too much deflection or to ensure the floor joist will be usable? I understand everyone will say this needs to be calculated, hire a structural engineer, etc., I understand this, but currently, there is no information about the building other than what can be measured. The live load on the joist is what I store on it myself, and it is difficult to know how much stuff one will load on. Or what one wants to store up there "maybe a lathe of 10 tons" Hope you understand. It's just the imagination that sets the boundaries and I just want to know what you would dimension with and consider reasonable. In the current situation, it might become a party floor up there that should handle a barn dance with 50 people.
I have an almost square house measuring 11*9m with a center wall on the ground floor. This center wall is to be removed to make the workshop more usable and the loft above more stable in the floor structure. The center wall consists of wooden posts about 100*100mm thick, these vary, between which some kind of stone/brick has been built in the cavities, the posts are currently about 1.5 - 2 meters apart, an old building built surely a bit on HO.
The function of the center wall is to support the floor joist above, the house body is on stone up to about 3m after which a wooden sill has been laid on which the rafters rest, "I can imagine a barn looks similar to this."
So the floor joist rests on the stone wall and on the center wall. The span is 9 meters and the center wall is in the middle.
Hope you get a good picture of the current situation. The floor joist is quite slender, 7'20 cm on the beams and C/C 100-120 span 4.5m.
I intend to help the floor joist by replacing the center wall with a type HEB180 or alternatively HEA200, with 3 support points, I would prefer not to have 4, the span is about 11 meters. My idea is to aim for 3 with a larger dim on the beam, rather than 4 with slimmer ones. But there are limits this should be handled with of course.
In addition to this, I plan to help the old floor joist with 2 additional beams so that the span doesn't become 4.5m in depth. I will do this with 2 IPE180 with 3 support points, thus reducing the distance to 2.25.
Thus, my question is what kind of beam do I need to be on the safe side to avoid too much deflection or to ensure the floor joist will be usable? I understand everyone will say this needs to be calculated, hire a structural engineer, etc., I understand this, but currently, there is no information about the building other than what can be measured. The live load on the joist is what I store on it myself, and it is difficult to know how much stuff one will load on. Or what one wants to store up there "maybe a lathe of 10 tons"
Hope you understand. It's just the imagination that sets the boundaries and I just want to know what you would dimension with and consider reasonable. In the current situation, it might become a party floor up there that should handle a barn dance with 50 people. Anyone who has done something similar and has experiences?