Getting across ceiling joists from below - tricks of the trade.

[FatAlan]

In the day and age of ..how many downlights can we get into one house, I'm intrigued to know what tricks / techniques folks use to install multiple downlights into an existing ceiling in replacement of a central pendant. In particular, once having located the joists, how do you get the cables across or through the joists with minimal damage to the ceiling? Is it a case of just cutting an access hole in the ceiling across the bottom of the joist so that you can see both sides with enough space to drill a hole (building regs compliant). Does anyone cut small notches and protect with steel plates for instance?

 

[Dustydazzler]

If possible wire from above by lifting or cutting floorboards or via loft space / eave voids

I’m not a fan of ‘notching’

You can cut holes and pop the circular cut out back in

 

[Baddegg]

With you dusty, if I can’t get the floors above up them it’s cut neat round holes (sharp holesaw) and timber across and reinstate the cutouts, bit of fine filler and all’s good

Edit.....unless it’s artex then it ain’t getting done..

 

[Squid]

Do the job properly,

joking apart what access do you have from above, how many lights, in what direction are the joists layed out in etc etc?

 

[Wilko]

Hi Al, at risk of revealing bias here, but notches are for Plumbers. I think I could run a C&G course in upside down temporary mini golf course design and construction.

 

[Leeroy]

New builds nearly always cut holes in ceiling and drill through joists them patch back in with batten and the plasterboard that has been cut .

Notching underneath joists is not permitted .

 

[Rpa07]

I always say “you gotta break eggs to make an omelette” - once I’ve explained this 3 or 4 times they let me holesaw loads of holes (I use 100mm so I can get my arm in there) to drill your joists.
It’s the careful planning of where the joists are so you can do as few holes as possible to route your cables.
It’s music to my ears when they state that the ceiling will be skimmed!

 

[Dustydazzler]

With you dusty, if I can’t get the floors above up them it’s cut neat round holes (sharp holesaw) and timber across and reinstate the cutouts, bit of fine filler and all’s good

Edit.....unless it’s artex then it ain’t getting done..

Artex is horrible to repair

I just done a small job a kitchen where the electrical job took about 25 mins after cutting a small hatch in the ceiling

The making good and applying a fresh splodge of artex to the new bit of boardi put in took about 3.5 hours in an attempt to make it look like the ceiling hadn’t been cut

 

[Dave5678]

Does anyone cut small notches and protect with steel plates for instance?

I'm pretty sure the building regs say that you can only put a notch in the top side of a joist, not the bottom, in the region that is between 0.07 and 0.25 of the span. Electrical regs then require you to protect the cables against penetration. Better to route your cables in the zone where you can drill holes through the joists.

 

[FatAlan]

Cheers folks. Just checking I wasn’t missing a trick. I like the omelet scenario