Leca beam over port - Alternatives?

[MagHam]

I am planning to build a garage 6x6.6 = 40m2. The idea is to use lecablock on an uninsulated slab since I am not looking for insulation but prefer thermal inertia. Furthermore, the facade will be plastered in the same style as the main building's rendering, which provides a good base for this.

Above the 2500mm door, a beam is needed as the last course. On this, supports for 2 of the roof trusses will be placed.
There are different options here:
- LecaBeam 2990mm which is terribly expensive but saves time, of course. Supports 5 kN according to Weber
- Place an I-beam (which can perhaps be cast in?)
- Build a formwork on-site and tie lots of reinforcement to then vibrate down concrete.

Best practice? Experiences? Opinions?

 

[byggolle]

I always advocate for in-situ casting of everything (I'm the concrete piece). However, an engineer should do a proper calculation for loads, reinforcement, insulation, concrete quality, etc. You should probably contact an engineer for the steel beam as well. So the easiest might be an expensive leca beam where you already know what point loads it can take.

 

[MagHam]

Thanks for the response.

I can calculate a typical I-beam myself if I dig out the old schoolbooks or do a bit of googling...

But I'm inclined to cast a concrete beam on-site in the form, just as you suggest.
I've noted on old prefabricated ones that they tend to be reinforced in a diagonal truss pattern. It's more difficult to calculate the strength achieved oneself in this case (though one can always overdo it a bit).
You definitely don't want it to give way and collapse on someone :eek: