Max load on beam

[olahall]

For spans of 6-7 m, glue-laminated timber or steel beams are advisable. While you can certainly build a truss construction, it won't be small and neat...

Truss construction...
Are we then talking about my latest sketch?

This one...

 

[tommib]

If that picture is from the side, then it is a truss construction, yes.

Träguiden is a good place to start for formulas...

https://www.traguiden.se/konstruktion/dimensionering/berakningsexempel/bostadshus/dimensionering-av-en-rak-trabjalke/


I can't help you offhand since I haven't calculated this kind of thing.

 

[olahall]

I don't understand that image at all. Take a photo and explain how and where you're thinking of putting the roof. But there are glulam beams that are much better for large spans. Regardless, it's the snow load on the roof that will determine your beam.

I've uploaded several images, so I'm not sure which one you're referring to. :/

Hard to capture how I'm thinking in a picture.

I have a drawing...

I want to have a plastic roof over the sofa.
At the bottom of the drawing, there are posts I can use, which currently have a plank on them.
At the top of the drawing, there's a garage, whose gable is against the top edge of the drawing.

So, I just want a roof over the sofa.

 

[olahall]

If that picture is from the side, then it's a truss construction indeed.

Träguiden is a good place to start for formulas...

[link]/

I can't help you off the top of my head as I haven't calculated this kind of thing.

...if I'd understood these formulas, I could calculate it myself.
Was hoping some construction genius could help me here...

 

[Magnus E K]

Two ideas: Dismantle the roof on October 15 and put it back up on April 15 to avoid dealing with snow load. How tall is the wall behind the sofa? Maybe it's possible to build a "hanging roof," especially in combination with the first idea.

 

[GoC]

Am I understanding you correctly that you want a bearer where you will place roof rafters and a roof above the sofa? You will definitely need a laminated beam to support that construction, both for wind load and snow load. You can manage the snow load by putting up a post in the middle of the bearer in the fall and removing it in the spring. Because you won't be sitting on the patio then anyway. But regardless, I don't think you'll get away without a laminated beam; it's a substantial span, even if the beam is only loaded on one half.

 

[GoC]

Two ideas: Dismantle the roof on October 15th and put it back up on April 15th to avoid snow load issues. How high is the wall behind the sofa? Maybe it's possible to build a "hanging roof," especially in combination with the first idea.

You put up one or two posts in the fall to handle the snow load.

 

[olahall]

Two ideas: Dismantle the roof on October 15 and put it back up on April 15 to avoid accounting for snow load. How high is the wall behind the sofa? Maybe it's possible to build a "hängtak," especially in combination with the first idea.

What is a “hängtak”?
The height behind the sofa is 2 meters today. But it's adjustable, in the worst case.
Ideally, I'd keep it at 2 meters.

 

[Magnus E K]

What is "hängtak"?
The height behind the sofa is 2 meters today. But it is adjustable, at worst.
Preferably, I keep it at 2 meters.

I don't know what the correct architectural term is. I envisioned something like this (viewed from the side):


But it probably requires certain specifications for the upper attachment point, so if the entire wall is only 2 meters, it might not be possible.

 

[olahall]

[image] [image] Can I get a layman's explanation of how much weight a rule of treated wood can support?

I'm wondering what a 45x220 board, 4500 long (placed on the "height"), can support in weight.

If I attach it at each end, how many kilos can I then place in the middle, before it starts to bend... and when does it break?
(Image A)

Another question...
If I take two boards (same as above), about 3 meters long. Attach one on one side, the other on the other side... towards each other so they meet. How do I attach them best in the middle (where they are joined), so they can support as much weight as possible?
(Image B)

[image]

I've uploaded several images, so I'm not sure which one you're referring to. :/

It's hard to convey my thoughts in a picture.

I have a drawing...
[image]
I want a plastic roof over the sofa.
At the bottom of the drawing, there are posts I can use, which currently have a plank on them.
At the top of the drawing, there's a garage, whose gable is against the top edge of the drawing.

So, I just want a roof over the sofa.

Could it work if I build a truss construction on-site?
Let's say I prop up (temporarily), so that the truss construction is curved upwards a few centimeters. I build a neat framework, on which I then place the slimmest possible rules to attach the roof to.

Then I remove the posts... so the natural curve makes the construction straight (straighter).

 

[tommib]

How high were you thinking of having the ceiling above the sofa then? If there's only 2 m without the ceiling and ceiling joists, there won't be much left after you've put in reasonably sized joists.

 

[olahall]

I don't know what the correct construction term is. I was thinking of something like this (seen from the side):

[image]
But it would probably place some demands on the upper attachment point, so if the whole wall is only 2 meters, it probably won't work.

Aha, you're thinking of attaching the roof to the rear part instead...!
Hm!
Yes, that would mean I might need to set up some new posts in that case... quite sturdy ones maybe?

But the roof would in that case "hang" out about 3 meters.

Would that work??

 

[Pasjostrom]

Is there no possibility to have one or two posts? Glulam is likely the most reasonable solution, but the span of 6-7m is still a problem.

 

[olahall]

How high were you planning to have the ceiling over the sofa then? If there's only 2 m without ceiling and ceiling joists, there won't be much left after you've put in reasonably dimensioned joists.

I mean, 2 meters is enough at the lowest. You'll only be sitting there anyway.
My idea was 2 meters at the back, so to speak... then upwards. However, I can only mount the beam at about 240 cm at the highest (just over).

 

[olahall]

Is there no possibility to have one or two posts? Laminated wood is probably the most reasonable solution but the span of 6-7m is still a problem.

Possibility...yes, but they will end up in the middle of the floor on the deck, which I want to avoid.

If I had been okay with posts, this wouldn't be a problem