internal bifold door span, joist/beam suggestions please

[Mr Chibs]

I'd like to put in a room divider to split a large room, and have bought some internal oak bi-folding doors.

At the moment, I haven't built a frame for them to sit into.

I've got a width of 3.8m (masonry walls both sides) and ceiling height of 3.3m.

I was thinking (dangerous I know) of using a couple of wooden joists, something like 175x50 bolted together to give me something to fix the header track into. Would this method work, or is sag likely to be an issue at a span of 3.8m?

Would steel box section be suitable, or can anyone suggest something I've not thought about?

Any advise appreciated.

 

[Notch7]

I'd like to put in a room divider to split a large room, and have bought some internal oak bi-folding doors.

At the moment, I haven't built a frame for them to sit into.

I've got a width of 3.8m (masonry walls both sides) and ceiling height of 3.3m.

I was thinking (dangerous I know) of using a couple of wooden joists, something like 175x50 bolted together to give me something to fix the header track into. Would this method work, or is sag likely to be an issue at a span of 3.8m?

Would steel box section be suitable, or can anyone suggest something I've not thought about?

Any advise appreciated.

I think you might need something a bit beefier TBH. Have you space for deep joists, say 8 x 2 or 9 x 2 doubled up?

In any cade you might be wise to pack the bifold frame a few mms to counteract sag which you will get.

 

[Mr Chibs]

Cheers Notch

OK, had a re-measure, and have revised sizes, 3.3m wall to wall, I have doors 3m wide, was intending 150mm nib each side.
I have 800mm from door track to sloped ceiling, so yes, I could easily upsize the timber.

Since this mornings post, I was wondering if a flitch beam might help... or do you think I'm over complicating it?

Thanks again

 

[Notch7]

If you have the space just use timber.

A flitch beam is quite a bit of work and theres the potential for the steel to be just where you track fixings want to be.

I have used glulam beams often in orangeries for bifold doors, although they are often 90 x 315 section.

Id be tempted to use 250 x 50 2no screwed and glued together.

Mind you Im slightly wondering if you need to be concerned with lateral stability, you dont want it wobbling as the doors are slid and opened. In which case you could make a box beam out of studwork, say 200 x 50's sat upright and 150 x 50's flat. Just a thought, if the beams is well the ceiling it might want to be nice n stiff.