Structure for Gable window

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OrangeJuice09

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I’m having a single storey extension built and have query about the structure required for a gable window. There are two glazed areas, triangular piece of glass for gable and doors below. I would like to keep the horizontal bar between the top glazed section and the doors to a minimum height for sight line reasons and indicated by the orange line.
Could someone suggest the type of structure / steel needed please? (I think the orange line and the red line (upstands) will be in steel, this is just an idea I’ve had - however the builder said no steel is needed other than the lintel.


Thanks again
 

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Yes a vaulted ceiling. The plans have a 75mm x 225mm ridge beam. (I've added plan drawing to my post, though it lacks the details)
 
Who has done the plans and specified the size for the ridge beam/rafters etc? Are they not designing the rest of the structure?
 
jks7492 said:
Who has done the plans and specified the size for the ridge beam/rafters etc? Are they not designing the rest of the structure?
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The architect designed the entire extension which is almost built, including the flat roof section. Unfortunately, not much detail was provided for the gable. I know, its not good though I have asked for the detail I think the architect cannot deliver :(
 
OrangeJuice09 said:
The architect designed the entire extension which is almost built, including the flat roof section. Unfortunately, not much detail was provided for the gable. I know, its not good though I have asked for the detail I think the architect cannot deliver :(
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the ridge is structural and has to be fully supported to stop the roof spreading.

the solution is either a cranked steel beam which transfers the loads to the sides, or you need a steel post below the ridge and a steel beam above the patio doors.

even without the roof loading issue, the patio doors need something above to give them stability.

How wide is the brickwork either side of the patio doors - there needs to be consideration for lateral stability.


Has this design not been to a structural engineer - it needs to be, I wouldn’t go an further until it has been.
 
Hi Notch7, I agree on the two options, either a cranked steel or steel post between ridge and patio doors. I'm favouring cranked steel option.

I've updated image, is this what you mean by a crank steel (in red) - The Orange line indicates a thinner steel section to preserve sight lines.

The width of brickwork either side is 490mm (internal) - Is there a minimum return (I wanted to increase the width of the Patio Doors), resulting in a retun of 390 (internal) either side ?
 

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OrangeJuice09 said:
Hi Notch7, I agree on the two options, either a cranked steel or steel post between ridge and patio doors. I'm favouring cranked steel option.

I've updated image, is this what you mean by a crank steel (in red) - The Orange line indicates a thinner steel section to preserve sight lines.

The width of brickwork either side is 490mm (internal) - Is there a minimum return (I wanted to increase the width of the Patio Doors), resulting in a retun of 390 (internal) either side ?
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675mm brickwork each side externally is probably fine -especially given the flat roof extension will act as a buttress (for lateral stability)

Yes thats a cranked steel -the welds etc have to be suitable to take the load -so it needs specifying by a SE

You will still need a strong steel for between the patio doors -to resist flex up down and in out -you dont want wobbly doors -maybe a SHS

As Im sure you are realising -the gable end needs a lot of thought, it requires a structural engineer to design it and really the detailing should be done by an architect -there are various issues to cover including thermal bridging concerns, etc etc

Tony on this forum is a SE, he might see this thread and comment -but ultimately you need a SE to design it for you


Is there no detailing on the building regs drawings you have already?
 
Notch7 said:
675mm brickwork each side externally is probably fine -especially given the flat roof extension will act as a buttress (for lateral stability)

Yes thats a cranked steel -the welds etc have to be suitable to take the load -so it needs specifying by a SE

You will still need a strong steel for between the patio doors -to resist flex up down and in out -you dont want wobbly doors -maybe a SHS

As Im sure you are realising -the gable end needs a lot of thought, it requires a structural engineer to design it and really the detailing should be done by an architect -there are various issues to cover including thermal bridging concerns, etc etc

Tony on this forum is a SE, he might see this thread and comment -but ultimately you need a SE to design it for you


Is there no detailing on the building regs drawings you have already?
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Thanks for the above, appreciated. There is no details other than what the OP. I wil try to find a SE today.
 
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