Christian McArdle wrote in message
et...
Isn't the correct way to drill holes through the joists at half
depth and run the cables through? The joists are only 70mm deep,
so would drilling holes all over the place weaken them?

No, it is acceptable if the space is not likely to be used. Indeed,
it
prevents the need to drill the joists, thus weakening them. As you
are now
converting the area into a storage area, you'll have to solve the
problem.

This can be done by drilling the holes in the prescribed manner (you
should
only drill holes in certain defined parts of the joist of certain
prescribed
sizes and quantities). You can also add battens to the joists, so
the
flooring sits on those instead.

If your joists are only 75mm, then they are very weak. If the span
is quite
large also, then the storage capacity of the area in terms of weight
will be
pretty low, especially after the weight of flooring/battens is
considered.
Don't start putting large boxes of books up there.

Christian.


Thanks, Christian, I was a bit worried about holey joists. They are
nearer 70mm (2¾ inches) than 75mm. In fact I'd already laid some
boards on battens so maybe that's the way to go. The span is 4 metres
max. Are there tables of prescribed dimensions and spacings etc
somewhere I can access?
Just off to move those large boxes of books!

Rob


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