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Tim S Tim S is offline
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Default Is angle iron adequate for lintel?

mike coughed up some electrons that declared:

Does anyone know if a 3.5 inch angle iron over a 12 foot span is
adequate to support 8 foot of brick wall above?

A 12 foot wide picture window was replaced in a cavity gable wall,
with the result that the outer skin of the wall started to collapse.
There's a lintel on the inner wall but the outer wall was just built
off the original frame.

The collapsed part of the wall was taken down, the angle iron
installed (I didn't see it installed but I'm calculating it's 3.5
inches as it's not the full width of the brick but the outer edge is
visible), and the brickwork rebuilt.

It wasn't inspected by BCO.

To me it looks like there's a noticeable bow in the middle.


Hi,

I'm not a structural engineer...

Do you have any known history on who did the replacement and when?

Presumably the original picture window supported the wall with regular
uprights? What type of window or door is there now? (uPVC windows *can* be
built with internal structural supports, but if the installer didn't
bother...)

I doubt 3.5" angle iron (but what thickness???) is going to snap, *but* 12
foot is a long span and 12x8 foot of brickwork is very heavy. Instinctively
it doesn't feel right by a large margin (I've seen it done when the iron
was in the form of an arch, but not straight). The fact you are seeing a
bow in it confirms it's not good IMO.

Irrespective of whether it's likely to break, it would be wise IMHO to get a
couple of Acrow props under it pronto, to keep it stable in the meantime
(they're cheap enough to hire).


I can see why angle iron would be used so as not to disturb the inner
skin, but it seems quite a long span, and that some sort of U-shaped
construction on its side that would allow two or three courses of
bricks to be built within the U would be required. How is the weight
of the roof factored in?


What's supporting the inner leaf? Where does the roof load go (often inner
leaf, but do you know for sure?)

Personally, over that distance, I'd consider a steel box lintel of some
sort.

You might find this interesting reading:

http://www.catnic.com/libraries/document/150.pdf



Is there a table or calculator online that deals with this? And
should it be BCO inspected?

Thanks.


I think you need to rectify this, and get the BCO involved - but watch this
space for more comments.

Cheers

Tim