On Fri, 23 Apr 2004 00:54:35 GMT, Ian Stirling
wrote:

dundonald wrote:
I'm laying flooring [1] in my loft. The wiring is simply thrown over the
joists rather than a hole drilled centrally through the joist and the wiring
passed through the hole. Is it good practice to cut a little nick out of
the joist, enough to lay the wiring for the flooring to flush with the joist
over the top? Is this detrimental to the structure?

Hi,

How wide apart are the joists? It's probably not that hard to get a
small drill in there and rethread the wire through the holes. If you
have an angle grinder a cheap wood bit could be cut down if necessary.

Yes.
Cutting out a 10% section of beam at the top reduces strength by at best
20%.
What about routing a groove in the chipboard?

If that's not possible and the wires are parallel to the joists in
some places, another alternative would be to rout a diagonal slot in
the top of the joist.

Anyone hazard a guess as to how much a diagonal 5*7.5mm slot in a
50x75 joist would reduce it's strength?

cheers,
Pete.