Re Tracing ceiling joists

[Deebrief]

I previously asked for advice on fixing a crack in the kitchen ceiling and
it seems it would be best to screw the plaster board up into the joist
somewhere above it.

However I know that the bathroom above has plastic tubing running through
the joists and I am worried about drilling into one of these.

How can I detect where the wooden joists are (The floor above has a tiled
floor).

Thanks


Dee

 

[Andrew Gabriel]

I previously asked for advice on fixing a crack in the kitchen ceiling and
it seems it would be best to screw the plaster board up into the joist
somewhere above it.

It should be already?

However I know that the bathroom above has plastic tubing running through
the joists and I am worried about drilling into one of these.

shouldn't need to screw more than half an inch into the joist
bottom. I think you just need to pray the tubes are not that
near the joist bottoms (they shouldn't be, but doesn't mean
they aren't). You don't need to drill first.

How can I detect where the wooden joists are (The floor above has a tiled
floor).

You can usually find them with a magnet, to find the screw or
nailheads fixing up the boards. That's why I don't understand
why you think you need to put more screws in?

 

[Woody]

It should be already?


shouldn't need to screw more than half an inch into the joist
bottom. I think you just need to pray the tubes are not that
near the joist bottoms (they shouldn't be, but doesn't mean
they aren't). You don't need to drill first.


You can usually find them with a magnet, to find the screw or
nailheads fixing up the boards. That's why I don't understand
why you think you need to put more screws in?

Knocking.

The ceiling will sound hollow away from the joists and flat/solid
where the joist is - and it helps if you already know which way
the joists run. If you have a strip light that will be screwed to
one single joist which will give you a good starting point. Knock
with you knuckle as you move away from the light going perhaps an
inch at a time.

Generally speaking the joists will be 16" apart in an older
house, or perhaps as little as 12" on a modern house, the
breakover time being 70's-ish.