"The Natural Philosopher" wrote in message
...
John Borman wrote:

So should I be worried that the guy that's installed central heating into
a renovated house cut a U section in the top of the beam ,of 1st floor.
That depends.

If its then had e.g chipboard nailed on top, a lot of the strength and
stiffness is restored.

No chipboard just t&g floorboards....

Note that the building regs tend to look at maximum defelection under
load, as ultimately failure load is way higher. You could have maybe 6" of
sag on a beam spanning 5 feet before it broke, but this is unacceptable in
a floor :-)