Bifold Doors

[JohnWils]

Hi all,

Been searching for this info for hours without success and ended up here!

My question - upvc bifold doors, what is the max dip (deflection) allowed in the outer frame, top of the outer frame? Does anyone at all know the answer to that one and the BS or reg that specifies it. Would be so grateful for any help.

Thanks in advance

 

[freddiemercurystwin]

Why would it matter provided they work OK? Prolly better off asking in the windows section anyway.

 

[Paulg31]

Hi,

I guess you are referring to the max deflection in the steelwork or lintel over the opening.

Is the bifold door bring site measured or do you you have a set dimension for structural opening to build?

If it's site measured as long as the beam is sizes for something like span/250 deflection under total load I can't see it being a problem.
If you're building a set structural opening as long as you allow for whatever deflection your structural engineer calcs you should be fine.

 

[JohnWils]

Thanks for answering Paul, I mean the actual outer frame of the door, dipping in the middle.

 

[Nakajo]

Dare we ask why

 

[^woody^]

It can't dip else the rollers and doors will bind.

 

[tony1851]

(Slightly off topic here, but there was a thread on here 2 or 3 years ago about a client who had a large flat-roof extension with a brick parapet wall, and wide bifolds.
The SE had specified a steel beam to carry the parapet over the opening, and only allowed for live load deflection (eg snow load). Because the BS code for steelwork only specifies a limit for live load deflection, the SE appparently forgot to allow for the dead load deflection caused by the parapet wall itself, and the doors wouldn't fit).

 

[JohnWils]

Morning all,

Thanks for your replies. Bit of a long story but in short. Had plastic bifolds fitted and there is a small bow of 2 - 4mm in the top of the outer frame. Now this may be totally fine. But I need to know which British standard or doc covers this.

Thanks

 

[tony1851]

Now this may be totally fine. But I need to know which British standard or doc covers this.

Is it fine or isn't it? Are the doors jamming?

 

[JohnWils]

The doors operate fine. But that's not what I'm trying to get at. As with most structural elements, there are BS and/or approved docs that specify limits and detail. I need to know what the permitted deflection is and where this information is set out.

Thanks

 

[tony1851]

I may be wrong but I doubt you will find any BS which stipulates maximum permitted deflection in bifold door frames. Presumably tolerances will vary according to the limits individual manufacturers allow for their systems.
In terms of the beam in the structural opening of the building itself, there are deflection limits specified in various structural codes, but these are generally advisory only.

 

[JohnWils]

Thanks Tony, that's really helpful. Will try looking at the manufacturer info. In the meantime, any other input appreciated.

Thanks again

 

[freddiemercurystwin]

You'll get more assistance if we can understand the issues.

 

[^woody^]

With any manufactured system, it is always the manufacturers specification that takes precedence.

 

[JohnWils]

Excellent, thanks to all for your input. Anything else feel free to add.

Thanks,
JW