Steel over bifold

[Sunil237]

The structural engineer provided this as the alternate UB 356x171x67. The RHS weighs 500kg, where as the UB will be 600kg, making things significantly more challenging logistically.

 

On 20/11/2024 at 11:05, Russell griffiths said:

Build the opening smaller then, stick to around 5m. 
having built two new houses and multiple renovations with this type of extension on the back I can’t think of a reason for such a big door. 
we where going to have two sets of 5m wide doors in the back, but went for one and a picture window, and our view out the back is probably better than 95% of peoples, we just couldn’t see it being used fully, and the impracticalities were many. 
 

A 6.5m wide opening looks good on the fancy architects plans. 
but that is all. 
pros and cons of such a big opening. 
 

CONS. 
future deflection effects door working properly 

Expensive steel

more calculations 

very expensive door

problems with such a door in the future 

how many days in England will you actually want it fully open

smaller reveals on the inside restricts furniture and kitchen layout. 
 

PROS. 

 You can show your friends what a big door you have. 

I really do appreciate the complexities created by such a large opening, infact my wife wanted 7.2m initially!! I've talked her down to 6.4m so far..

 

Is there a reason for 5m specifically and do all these issues drastically reduce at this mark?

[saveasteading]

40 minutes ago, Sunil237 said:

Is there a reason for 5m specifically

No. In simplistic terms, the implication of changing length is the square of the span, so any change is significant.

Then when a section of steel doesn't quite have the capacity, there is a jump up to the next weight. Not all the steel sections listed are readily available.

The steel is going to be £/t. 

[scottishjohn]

6 hours ago, Sunil237 said:

The structural engineer provided this as the alternate UB 356x171x67. The RHS weighs 500kg, where as the UB will be 600kg, making things significantly more challenging logistically.

any digger or telehandler that can lift 500kgs will lift 600kg 

 quite sure if you going for a "genie" same will be true 

you certainly not lifting either by hand 

so no problem 

 if you really want such humungus opening then have  slim post in the middle ,that will change everything .could be round or square  and could be bolted on the sides  to the beams -making each one half the length  and  a lot lighter

 as now the span is only half to a support  and willl you really notice a post that much? - i doubt it  if lined up with  joint in the framing  

 on the other side have you considered how much heat that size hole is going to add to that room when sun iis out and how much extra heat loss there will be with that size of glass 

 at that size you are going to be thinking about a Brise soleil shading system  tyo stop overheating in height of summer 

Edited yesterday at 07:35 by scottishjohn

[Russell griffiths]

What we haven’t seen is a plan, show us a layout of what you want to build. 
I will stand by my thoughts that a smaller door would work. 
or go even smaller and a large picture window. 
has the SE said anything about supporting this beam. 

[Sunil237]

Thanks guys, attached the PDF of the floorplan here.

 

Heating has been considered as I have a heatpump going in, the engineer has done a full heat loss calc

1.pdf

No the SE hasn't suggested supporting the beam, he was confident with the rectangle box beam though.

Edited yesterday at 11:00 by Sunil237