Mary Fisher wrote:

"Tony Bryer" wrote in message
...

In article , Michael
Walsh wrote:

The first was an engineered flooring joist it was made from 75mm
square timber frame with steel diagonal ties and occasional 75mm
square reenforcing. It came lengths up to 5M. It seemed like a good
idea as it allowed easy running of plumbing and electricals through
the joists without drilling as they were hollow and it is supposed
to have better flex and load carrying characteristics

Catnic tried an idea like this about 20 years ago. The diagonals were
V shaped galvanised pressed steel, with the ends and point being
stamped out to form nails like the plates used to assemble trussed
rafters and pressed into the top and bottom members in a similar way.
They didn't catch on.


What were the reasons for it not catching on? Just too new, people too
suspicious of something unfamiliar? Presumably it had been tested and proved
to be suitable.

Basically its actually more expensive than just whacking down 6x3 softwood.

To make the most out of all this stuff you need a slightly different
approach to design.

If you mass produced a complete celing/floor using them, so the blokes
on site just laid it en bloc, it might be worthwhile.

All this clever stuff means you have to change teh way things are done.
Pre-fabbing is vheaper, but you have to think about plumbing and wiring
eairler, and have things like cranes on sie to lift in prefab chunks.




Mary