On Wed, 19 Dec 2007 10:21:31 -0000 Dave Baker wrote :
We are having work done on our house and it involves a big and heavy
steel beam to support most of the back of the house. It is probably
about 1000kg and 7m long (300mm x 300mm).

Firstly a quick calc shows it shouldn't weigh anything like that much.
No more than half a ton even if it's made from 1cm thick metal

300x300 UCs come in 7 rolling weights from 97 to 283kg/m so 1000kg is
perfectly possible. If it's possible to lift each end in turn by
degrees, then the lift weight is half this.

I hope the designer/engineer has satisfied himself as to the adequacy of
what holds this beam up!

--
Tony Bryer SDA UK 'Software to build on' http://www.sda.co.uk