Installing spotlights in living room with joists

grumbler

theonlywayisup said:

35har1old said:

mi-key said:

dil1976 said:

grumbler said:

tacpot12 said:

You will probably need to route cables through the joists and this could be tricky unless you have a right angled drill or drill attachment. You need to know where it is safe to drill through the joist, and also how to isolate the existing lighting circuit. It's quite likely that you will have to cut holes in your ceiling to get the drill into the ceiling, although you might be able to drill via the holes for the downlighters in some cases.

I think it's more common to make small notches at the bottom of joist then making holes in the plasterboard for drilling through the joists.

You shouldnt make notches in the bottom of joists just the top to help keep the strength.

https://www.eden.gov.uk/planning-and-building/building-control/building-control-guidance-notes/notches-and-holes/

Taking a 10 - 20mm notch out of the bottom of a 2x4"  joist makes no noticable different to the structural strength

Downstairs joist are normally 8x1.5  (122 mm x 38 mm)

Joists will be the size required for the span.  

For the biggest span of this floor. Joists are the same in big and small rooms.

mi-key

On an 8 x 1.5 then will make even less difference taking a 10mm notch from the bottom.