Time to start tearing down a load-bearing interior wall now...
The intermediate floor will be suspended from a Kerto-S beam, 45*400, 3600 mm long, embedded in a wall on the floor above. It will be supported by two 90*90 glulam posts that will be embedded in the walls on the floor below. The estimated vertical load is 15 kN per column.
Then the question arose, what should the posts have as a base???
I see a few options;
1. Placed on the floor joist that the wall studs stand on, on one side it is the sill in that case. The pressure in this case will be perpendicular to the grain direction where wood is the softest, so the question is whether it will compress the joist in the long term?
2. As above but with a steel plate, larger than the post, which distributes the weight over a larger area?
3. Cut out a section of each floor joist and place the posts against the concrete slab, with a moisture barrier in between?
4. As above but with a larger cut-out and a steel plate for pressure distribution?
The concrete slab is 100 mm thick in the middle and over 200 mm at the outer wall side.
We currently have two steel beams embedded in different places in the house with longer spans, one of which supports a 5 m exterior wall for the upper floor with rafters on this wall. These are only supported by three 45*120 studs nailed together, and these stand directly on the 45*120 floor joist/sill, and this seems to have held for 37 years anyway. Hence the consideration of placing it on the floor joist with a pressure-distributing plate in between.
For those who know, what is appropriate in this case. Options 1 and 2 are the simplest to do.
The intermediate floor will be suspended from a Kerto-S beam, 45*400, 3600 mm long, embedded in a wall on the floor above. It will be supported by two 90*90 glulam posts that will be embedded in the walls on the floor below. The estimated vertical load is 15 kN per column.
Then the question arose, what should the posts have as a base???
I see a few options;
1. Placed on the floor joist that the wall studs stand on, on one side it is the sill in that case. The pressure in this case will be perpendicular to the grain direction where wood is the softest, so the question is whether it will compress the joist in the long term?
2. As above but with a steel plate, larger than the post, which distributes the weight over a larger area?
3. Cut out a section of each floor joist and place the posts against the concrete slab, with a moisture barrier in between?
4. As above but with a larger cut-out and a steel plate for pressure distribution?
The concrete slab is 100 mm thick in the middle and over 200 mm at the outer wall side.
We currently have two steel beams embedded in different places in the house with longer spans, one of which supports a 5 m exterior wall for the upper floor with rafters on this wall. These are only supported by three 45*120 studs nailed together, and these stand directly on the 45*120 floor joist/sill, and this seems to have held for 37 years anyway. Hence the consideration of placing it on the floor joist with a pressure-distributing plate in between.
For those who know, what is appropriate in this case. Options 1 and 2 are the simplest to do.
When a 90x90 post carrying 15 kN vertically lands on a floor joist that is 45 mm wide, the pressure on it becomes approximately 3.7 MPa, which is a borderline case. Is it not possible to reinforce the floor joist just beneath the post itself with two upright stud pieces on either side, resting on the concrete slab?
Thank you.
The floor beam is probably 70 wide and 45 high except at the outer wall where it is 120 wide. In this case for me, the floor beam is the one lying on the concrete slab and to which the wall studs are attached.
Since the posts end up in the wall, the short beams would end up on the floor beam anyway, so I might as well cut the floor beam and let the post go down to the slab.
My idea with a steel plate, 10 mm, is precisely to reduce the point load.
The floor beam is probably 70 wide and 45 high except at the outer wall where it is 120 wide. In this case for me, the floor beam is the one lying on the concrete slab and to which the wall studs are attached.
Since the posts end up in the wall, the short beams would end up on the floor beam anyway, so I might as well cut the floor beam and let the post go down to the slab.
My idea with a steel plate, 10 mm, is precisely to reduce the point load.
Best answer
When they lie down that way, I call them sleepers. If it's 70 mm wide, I think it's enough. Otherwise, there's nothing wrong with pressure relief pads. You can make those in wood or plywood as well.
The problem is mainly obtaining a small piece of a material that is only sold in large sheets for quite a lot of money. If you disregard that, I would say 21 mm K-plywood. Oak also has good compressive strength.
They sell smaller pieces of steel, even to private customers. Might be good to know for others as well.
https://montano.se/category.html/stalplatta
https://montano.se/category.html/stalplatta