On Thu, 12 Feb 2009 13:29:55 +0000, Tim S wrote:
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.

That's my gut feeling, too - that's a heck of a lot of weight over quite
a long span, irrespective of the metal thickness. I can't offer any exact
calculations, but I certainly wouldn't want to put my head under that lot :-)