How to deal with these roof trusses

[Autodidak1]

Story of my life

But why does it have to be so complicated then?

• I want a bunch of trusses c-c 1200.
• There are truss manufacturers who both calculate and manufacture.
• The manufacturer nearby has timber for trusses c-c 600. He suggests setting them in pairs to achieve c-c 1200 where I want, but doesn't know the distance at which they should be nailed together...

I say - does it matter?
You say - don't make it complicated!

I say why truss when beam is simple

But you can also use double trusses, I would get a price for both and choose accordingly.

Good luck! No problems

 

[justusandersson]

Since I haven't seen any drawings, it's difficult to give specific comments, but there are some general aspects that might interest more than just TS. If a consultant, such as a structural engineer, has been hired to provide technical documentation for a building, it is very common in professional contexts for the specified component to be replaced with another considered equivalent or better. Such assessments should be handled by a KA. The point is that there is a design calculation in place that is tailored to the local conditions. If a supplier is to be used for calculations as well, there must be an agreement with the supplier that obliges them to take responsibility for their calculations.

 

[Relaxia]

Since I haven't seen any drawings

OK, I know it gets much nicer with pictures. I'll fix it...

|¯¯¯¯¯--------------_______8000mm
| 960mm______________|300mm
[ X ] 7200mm [ X ]

That is the shape of the truss. Quite basic, almost like a beam.

 

[Jeppenator]

Something similar?

 

[Relaxia]

What! Isn't my ASCII drawing good enough?

Well, kind of, but more triangular, like this one

or maybe more like


Or a combination

According to the lower image
H1: 300
H2: 960
S: 8000
S3: 120
S4: 6900
S5: 120

 

[fahlis]

This variant is probably better than the top one:

 

[justusandersson]

Looking at the span, a shed roof truss with common construction wood is fully possible. What complicates it a bit is that it should cantilever 80 cm beyond the outer support, thereby incurring a small torsional moment that requires a certain beam height over the support. This consideration plus the desire for a 7-degree roof pitch results in a relatively high height at the innermost point. An alternative to a truss is a shed-shaped glulam beam. I don't know which will be the cheapest in the end. Glulam tends to be about three times as expensive as regular wood in terms of volume, but here there's quite a bit of labor involved. Then there are some other aspects that could also influence the choice.

 

[Relaxia]

This variant is probably better than the one above:
[bild]

Exactly so

Now I've got an answer on how they should be nailed together. Upper and lower frame two nails c-c 200, diagonals c-c 300.

But does it have to be nails? And due to nail plates they won't be flush.
Say you happen to place a sheet of suitable material (plywood?) between the beams before screwing them together. Would that be negative in any way?