"Tony Bryer" wrote in message
...
In article , Dg wrote:
Although I agree that use of such a beam is a bad idea, it is
interesting to note the many houses built up to the mid 60's with
first floor walls built off a single or doubled timber joist.

Yes, but double joists nailed together have a lot of lateral
stiffness when compared with one of IMM's TJI beams which are
basically 50x50 top and bottom with a ply web.


Ahhh no ... there is no ply web, it is akin to 14mm OSB, but not ply.

They are also 90mm wide for typical domestic beams not 50mm, and 300mm deep.

It is unfair to compare the stiffness of one TJI beam against a joist, TJI
beams are designed with a complete homogenous floor system ... i.e. Silent
Floor
Where the Intralam ring beam and the glued & fixed deck all contribute to
the finished performance not one individual beam.


Rick