How to calculate glulam load-bearing wall

[jonaslatt]

Oh really? That's what I was told. That I can lay the beam over the rafters and have it supported by the last rafter before and after the wall that needs to come down. And everything rests on the walls that remain.
And of course, screw the beam into all the rafters.

I also googled this and found a picture of someone who had done this.

Is this completely off track?

 

[mdab]

I think that sounds completely wrong. Then the load-bearing wall wouldn't be necessary if everything can be supported by the remaining walls.

 

[mape17]

Visit www.moelven.se where you can calculate with their calculator what is required for different options.

You can relieve with a beam on top of the ceiling joist. For example, this is done at our place where it is relieved to remove two standing studs in a load-bearing outer wall.

Opening 3600mm. House width 8000mm
Roof slope 27 degrees, safety class 2, Climate zone 0-2, Concrete roof, insulation, self-weight 0.9kN/m2, snow load 2.5, shape factor 0.8
Result of the calculation:
Deflection 9mm
Required camber 81mm
Self-weight of beam 48kg

Required beam 90*315mm

 

[jonaslatt]

Now I'm getting worried. Does anyone know?

 

[mdab]

Yes, if you attach it to the outer wall, it's perfectly fine, but that's not the case here. Or have I interpreted it wrong?

 

[hangun]

Contact Moelven. They did calculations for me for free. I then bought glulam (about 20 pieces) for my house. I showed the municipality the calculation, and it was accepted as a structural document for the framework. Moelven was very service-friendly with this.

 

[nimhed]

Oh? That's how it was described to me. That I can lay the beam over the rafters and have it supported by the last rafter before and after the wall that's coming down. And everything rests on the walls that remain.
And of course, screw the beam into all the rafters.

I also Googled this and found a picture of someone who had done this.

Is this completely misguided?

How are you going to attach the new beam to the old rafters? Because your construction can never be stronger than that attachment.

 

[jonaslatt]

Now I have finally fixed the picture that shows. There is currently a wall between the kitchen and dining room.
http://www.garaget.org/mypage/gallery_image.php?user=11787&image=2325945

I was thinking of buying bent metal sheeting and screwing it between the roof trusses and the beam.

 

[nimhed]

Personally, I would have accepted a visible beam.

But if not, there is the solution of notching in a beam from underneath. Then you have to tear down to the visible ceiling joists.

I understand your idea with the beam in the attic. I don't think I would have dared that solution myself.

 

[jonaslatt]

What a job it turned out to be. Shouldn't it hold as I had planned? One end of the glue-laminated timber will rest on the gable and the other end is a concrete wall where the chimney goes. So I think those walls should be strong enough to support the two roof trusses that will be affected.

 

[jonaslatt]

Anyone who knows/believes my solution might work. As mentioned, it's two trusses that will be hanging in the air but are supposed to be supported with the help of the laminated timber beam.

 

[mdab]

What a job it turned into. Shouldn't it hold as I had planned? One end of the glulam will rest on the gable and the other end is a concrete wall where the chimney is. So I think those walls should be strong enough to support the two rafters that will be affected.

Oh my god, that's exactly what I've been asking about. If the ends have a stable attachment, then there are no issues! I understood it as you just planned to lay the beam on top of the rafters. And as mentioned, 90x315 is a sensible dimension for the purpose.

 

[jonaslatt]

And the gable and chimney are a stable attachment? Becomes 90x315

 

[mdab]

Sure, there should not be any problems.

 

[mdab]

Regarding how you then attach the beam to the rafters, you can, for example, do it like this.