6m X 8m Extension

[hankmarvin]

Hi,

I'm in the planning stages of a single story flat roof extension to my new house.

I'm planning to have a large opening on rear of extension and bi fold doors, I know I will need a beam between where the doors will hang.

Do I need a beam for each wall skin? Because biggest rsj I can see are like 203 x 133 x 25, which would only span just over one skin.



Has anyone installed these large span bi fold doors?


Thanks a lot
Hank

 

[tony1851]

Four metres is not excessive, and you don't need heavy rolled steel beams for that span. Catnic make lintels spanning up to 4.8m (and longer with some types).
They support both inner and outer skins, so no worries.

 

[hankmarvin]

They look perfect and as you say, fine for that span.

Could you sit another catnic/beam on that catnic (blocks built off it) to run to the corner of bathroom wall (the 3587mm line)? I want to use a beam there to cut the flat roof joist span so i have rough joist spans of 3 and 4 meters.

Thanks
Hank

 

[hankmarvin]

Does this look ok to people?

Using a combination of wall bearers and one rsj with a joist bolted each side and wood to wood hangers.


I was going to run the other way but I wasn't sure there would be enough block work wall above the opening beam/cat to be strong enough to take the wall bearer and roof weight, would be about 800mm block above opening.


Thoughts?