Patio roof - support beams of steel?

[MaWa71]

Hello!

We are planning to build a roofed deck at the back of our brick house, built in '64.

The deck will run along our living room which is recessed about 1.3 meters in the façade, and since we have a nice view over the fields towards the city center, we want as little as possible to obstruct the view.

The deck measurements should be 7m wide and about 3m deep (in addition to the 1.3m currently recessed in the façade), a total area of about 30 sqm. The roof will have Plannja's Modern cladding and an interior ceiling with recessed lighting. As we want a roof that looks light and modern, we would like the roof to be as "thin" as possible. d^_^b

Now to our challenge:
If we calculate on Moelven's site where you can make calculations for glued laminated timber, our deck gets the following suggestion:

7m long, 3m deep, 2 columns: supporting beam 90x360 or 115x360 (deflection 46 or 36mm). Roof joists LT 42x180 or 95x180 (deflection 11 or 5mm).
A total roof thickness of about 360+180+22+22+?= about 600mm which doesn't feel so light and modern

We can also choose to have three columns and then get the following suggestion:
Supporting beam 115x180 or 56x225. Roof joists LT 42x180 or 95x180 (deflection 11 or 5mm).
A total roof thickness of about 180+180+22+22+?= about 450mm which also doesn't feel so light :S

Can we choose to build with steel beams instead of glued laminated timber? Columns and supporting beams are in my mind. HEA or similar? Where can I find information/calculation models to see how strong the beams need to be?

Is there possibly someone on the forum who has experience with similar constructions or who would like to share their knowledge?

Thanks in advance!

 

[MaWa71]

Hello again!

I have tried to illustrate how we envision the patio.
The living room is slightly recessed into the facade, and there is currently a narrow terrace under a roof (1.3x7m), and we want to create a covered patio along the entire living room.

Anyone with any wise ideas on how we can realize the patio without having too many pillars/posts that block our view? :S

 

[anaitis]

It is certainly possible to do as you are thinking, but you should contact a designer for the correct dimensions.

 

[daviden]

But why don't you attach the rafters to the beam with joist hangers? Then the roof won't be much thicker than the beam's thickness, i.e., 180 mm. Starting to mess around with steel beams for a porch roof seems quite complicated, perhaps also expensive.

 

[MaWa71]

But why don't you attach the rafters to the beam with joist hangers? Then the roof won't be much thicker than the beam's thickness, i.e., 180 mm.

Hmm... But what should I do with the eaves then? I do NOT want a box clinging to the house. The patio roof should feel light and give an airy impression, and to create that feeling, the eaves should probably be at least 30 cm all around? :S

 

[Tjacko]

Unhook the roof beams, 45 is enough. Then it becomes 180+45. I myself built a storage shed this summer that is 4.5*7.8m with 180*42 glulam roof beams that I notched so the eave is only 45 high and 30cm long.

 

[MaWa71]

Remove the roof beams, 45 is enough. Then it will be 180+45. I myself built a storage room this summer that is 4.5*7.8m with 180*42 laminated wood roof beams that I notched so the eaves are only 45 high and 30cm long

Yes, that would be a possible solution...
Is it enough to have 45mm over the support beam then? In other words, can the roof beam hold the eaves up when snow and ice start to accumulate on the roof? :S

 

[Tjacko]

Yes, that would be a possible solution...
Is it enough to have 45mm above the beam then? In other words, can the roof beam hold up the eave when snow and ice begin to accumulate on the roof? :S

I haven't calculated it, it will be the first winter this year so we'll see
But 0.3m overhang isn't much and I find it very hard to believe it won't work. However, you should fasten the beams with joist hangers so they don't split

 

[MaWa71]

Realize I forgot to provide feedback.. The building permit fell through, so last summer we instead installed a 30sqm large patio awning over the wooden deck we built.