lintels over 8ft door - cavity wall

[calvert]

I'm putting a set of 8ft bifold doors in a single story building with cavity walls. i intend to use a 178 x 102 Universal beam over the doors themselves. Is there an alternative lintel I can use over the opening in the inner leaf of the cavity or should i use another U/B the same. Any advice appreciated, thanks.

 

[jeds]

It would help to know the overall make up of the wall. Sounds like you're planning to put the wall plate on the external leaf. How are you going to finish the wall externally? And why use a UB rather than a cavity lintel. I know a lintel is more expensive but it's a lot less messing about.

 

[^woody^]

Why would you want to put the beam on the external leaf?

 

[calvert]

Firstly, thanks for answering. It seems that the door frame needs to be fixed to a beam as a cavity lintel isn't rigid enough. I would much rather use a cavity wall lintel obviously. the wall is standard 9 inch concrete block, 100mm. what do you reckon? thanks.

 

[noseall]

Fit a timber beam over and tie it back to the internal 100mm beam and the rafter ends.

 

[calvert]

Sorry Noseall, when you say timber beam what size do you reckon it would need to be to give the rigidity for the doors to be reliable. I'd like to use green oak for the lintel but am I right in thinking that that might move too much?

 

[tony1851]

Sorry Noseall, when you say timber beam what size do you reckon it would need to be to give the rigidity for the doors to be reliable. I'd like to use green oak for the lintel but am I right in thinking that that might move too much?

I should think green oak would be the last material you would use for a beam in those circumstances, unless you don't mind the doors jamming.

 

[calvert]

Ok. That's the green oak out! Any more advice please?

 

[noseall]

2 x 150mm x 50mm bolted together.

 

[tony1851]

2 x 150mm x 50mm bolted together.

Would that not bend a bit?

 

[tony1851]

I'm putting a set of 8ft bifold doors in a single story building with cavity walls. i intend to use a 178 x 102 Universal beam over the doors themselves. Is there an alternative lintel I can use over the opening in the inner leaf of the cavity or should i use another U/B the same. Any advice appreciated, thanks.

What is the beam actually supporting. Flat roof? tiled roof? Gable-end? Will it be supporting the doors themselves?
Too many unknowns so far.

 

[noseall]

2 x 150mm x 50mm bolted together.

Would that not bend a bit?

Not if it is connected to the steel beam behind and borrows some turning resistance from the rafters possibly? Wasn't thinking of it supporting weight from above.
Is this a nine inch concrete block wall or a cavity wall? Confused.com.

 

[calvert]

The beam on the inner leaf is supporting a trussed tiled roof. The wall is cavity. Whatever is over he opening on the outer skin has to support the weight of the doors but as they run rollers in a track it has to be well rigid.

 

[^woody^]

You need an unequal angle (external) welded to a PFC channel (internal).

 

[calvert]

Thanks Woody. That sounds good. Is there any rule of thumb on the sizes or that a S E job?