Steel design for roof

[Selfbuildnewbie]

Our roof has ended up being quite complex. The solution that our SE has come up with so far for supporting the roof structure is to use steel beams spanning between the perimeter walls. The trusses will sit on top of the steel beams and rafters will span between the perimeter ICF walls to the steels (I've attached cross-sections below). 

To my untrained eye, that looks like a lot of steel and I'm guessing it will be quite expensive? The two large beams spanning from one side of the house to the other side would each be around 11m in length.

Perhaps this is the best (or only) solution but reaching out here in case there are any other options we should look into before we go ahead with this design?

[Selfbuildnewbie]

I also gather that it's not uncommon to use a SIPS roof with an ICF build.  Would welcome any opinions on whether that's a better route than a traditional cut/trussed roof for an ICF build? Plenty of info online but much of it is from manufacturers and therefore biased so we're unsure which is preferable in our case.

And whether a SIPS roof would reduce the need for so much steel.

[Conor]

That looks like quite a simple and neat solution for a complex roof. It's the hipepd end on your gable that's the culprit, along with the fact that there is no continuous ridge from front to back on the opposite side.

 

Edit. I've just seen your plans post. That's a ln unnesecsarily awkward roof design. Why is there not a continuous ridge from front to back and why is it a tad lower than the main ridge? It looks awkward and it's going to cost you more.

Edited October 20, 2022 by Conor

[Iceverge]

I think the SE has made as tidy a job as possible without simplifying the roof design. 

 

It won't be cheap but probably the most economical effort given the design. There's too many roof surfaces to make sips or even trusses cost effective. I count 18 separate planes. With a few pen strokes you could easily get down to 10. 

 

I think I had redrawn this sometime in Feb to a more buildable design. I'll have a poke on my laptop if you like when I get home .