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Discuss Getting across ceiling joists from below - tricks of the trade. in the Electrical Forum area at ElectriciansForums.net

FatAlan

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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?
 
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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

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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..
 
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S

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?

Screen Shot 2017-08-05 at 12.23.18.jpg
 

Wilko

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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.
 
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

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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!
 
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
 
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

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  • #10
Cheers folks. Just checking I wasn’t missing a trick. I like the omelet scenario :D
 

Midwest

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I did the whole thing, even a complete narrow section of plasterboard down, then reinstate the board. I’d always have the customer pay to have it plastered & decorated afterwards, unless it was only a couple.
 

suffolkspark

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I've had coving down before to run along when the joists direction isn't in my favour then just drilled a hole back up to get into the spaces I need
 

Welchyboy1

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Drill 100mm holes between joists, with a sharp hole cutter, about 3inches from one side of the joist, if you can

Use a 400mm long wood spade bit to drill through joists at appropriate height (ALWAYS check the other side of the joist before you drill through for pipes and cables)

Cut up 8in lengths of 1x2in roof batten(keep an eye out in builders skips they usually discard loads of off cuts), or the bits that come in oven packaging!
keep it in your van always

Use drywall screws to fix batten across holes and fix your circular cut out back in hole after wiring(paying attention to which way round they go and what one went it what hole, this is important for the best making good job)

Buy a bag of easi-fill and get some decent making good tools and fill holes
I personally use a little squirty water bottle to wet the area first and prevents your filler from drying out, but generally even a child can make a good job with this stuff its excellent!

Job done!
 

Welchyboy1

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Drill 100mm holes between joists, with a sharp hole cutter, about 3inches from one side of the joist, if you can

Use a 400mm long wood spade bit to drill through joists at appropriate height (ALWAYS check the other side of the joist before you drill through for pipes and cables)

Cut up 8in lengths of 1x2in roof batten(keep an eye out in builders skips they usually discard loads of off cuts), or the bits that come in oven packaging!
keep it in your van always

Use drywall screws to fix batten across holes and fix your circular cut out back in hole after wiring(paying attention to which way round they go and what one went it what hole, this is important for the best making good job)

Buy a bag of easi-fill and get some decent making good tools and fill holes
I personally use a little squirty water bottle to wet the area first and prevents your filler from drying out, but generally even a child can make a good job with this stuff its excellent!

Job done!
 

Gavin John Hyde

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Lost count of number of customers in new builds who in the rush to move in decide to lay expensive carpet and decorate. Then call a electrician to fit downlights if only they waited a week or so.
The one that annoys me is when you feed a cable between two parallel joists and find theres a timber going between them!
I am a fan of the hole being made.good with a timber and use the disc method.
Did just that last week in a new apartment, the ceiling and walls are all metal stud work so easy to find but due to amount of insulation and the sprinkler system being in the gap, had to cut holes to move lights.
Customer will be getting it sorted by decorators afterwords.
 

FatAlan

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  • Thread Starter Thread Starter
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Drill 100mm holes between joists, with a sharp hole cutter, about 3inches from one side of the joist, if you can

Use a 400mm long wood spade bit to drill through joists at appropriate height (ALWAYS check the other side of the joist before you drill through for pipes and cables)

Cut up 8in lengths of 1x2in roof batten(keep an eye out in builders skips they usually discard loads of off cuts), or the bits that come in oven packaging!
keep it in your van always

Use drywall screws to fix batten across holes and fix your circular cut out back in hole after wiring(paying attention to which way round they go and what one went it what hole, this is important for the best making good job)

Buy a bag of easi-fill and get some decent making good tools and fill holes
I personally use a little squirty water bottle to wet the area first and prevents your filler from drying out, but generally even a child can make a good job with this stuff its excellent!

Job done!
Good tips there. If you are drilling from one side of the joist through a 100mm hole how can you check to see if there’s anything on the other side without check via an access hole? Is that what you mean by 100mm holes between all joists that you’re routing between? :cool:
 

Rpa07

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Yes you’ll be needing to get the cable on the other side of that joist so you’ll either have a downlight size hole to check what’s on other side of joist or another 100mm to carry on the run.
It’s a thinker of a job at the best of times but doesn’t really matter if you cut a few wrong distanced holes at this stage!
 

Wilko

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Good tips there. If you are drilling from one side of the joist through a 100mm hole how can you check to see if there’s anything on the other side without check via an access hole? Is that what you mean by 100mm holes between all joists that you’re routing between? :cool:
Proper 18 hole golf course sometimes ... hopefully half get filled by lights :) .
 
Drill the holes for the downlights and use those holes as much as possible for feeding cables through.
If I cant see any existing cable runs through the new holes, I make an educated guess where existing cable runs might be through the joists (ie approx. 0.25 span of the joists and then drill further access holes (perhaps larger than the lights if necessary) and use existing cable runs rather than drill new holes - not always possible though.

Supporting cables is another issue though!!
 
Lost count of number of customers in new builds who in the rush to move in decide to lay expensive carpet and decorate. Then call a electrician to fit downlights if only they waited a week or so....
I was working in a similar one the other week... the owner has spent the best part of £25k for new kitchen, laminate flooring, walls all skimmed and redecorated everywhere... now she's decided she wants extra power sockets and tv/ethernet cables installed !
 

Leesparkykent

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by the time you’ve piddled around making holes, repairing holes, filling, sanding, painting etc it would be quicker and a superior finish to cut a length of the existing board out, opposite to the way the joists are running, run cables in and overboard the whole ceiling and tape and joint it.
 
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
Artex.......ASBESTOS Reinforced Texturing...happy cutting!
 

Midwest

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by the time you’ve piddled around making holes, repairing holes, filling, sanding, painting etc it would be quicker and a superior finish to cut a length of the existing board out, opposite to the way the joists are running, run cables in and overboard the whole ceiling and tape and joint it.
I've already said that, cuff. :)
 
I'm intrigued to know what tricks / techniques folks use to install multiple downlights into an existing ceiling in replacement of a central pendant.
I find surface trunking is the quuickest, complies with all the regs as well if you use suitable metal bands around the cables, job done.
 

telectrix

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devil's advocate...... if a prescribed zone in a wall is directly inline with accessories, cables < 50mm deep, why is a route between 2 downlights in a ceiling not permitted as a zone, when the cables are just above board (<50mm)?????
 

Welchyboy1

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by the time you’ve piddled around making holes, repairing holes, filling, sanding, painting etc it would be quicker and a superior finish to cut a length of the existing board out, opposite to the way the joists are running, run cables in and overboard the whole ceiling and tape and joint it.
Obviously the idea is you never get involved in the sanding and painting of the job, thats explained to the customer day dot. thats their look out to redecorate

You talking probably 3-4 holes for 6 downlighters max, the holes get replaced and the cuts get filled, job done walk away, everyones happy, you get paid

If the customer chooses to re-skim the ceiling then thats up to them surely and doesnt delay you getting paid

convince me, that will not ALWAYS be quicker, tidier and cheaper for everyone involved than re-boarding/(re-coving?), skimming and repainting a whole ceiling, considering its likely to be working above kitchens/bathroom suites that are not being replaced

then coming back to 2nd fix

your just making a load of hard work for yourself, and potentially pricing yourself out of the job!
 

Leesparkykent

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the idea is you never get involved in the sanding and painting of the job, thats explained to the customer day dot. thats their look out to redecorate

the holes get replaced and the cuts get filled, job done walk away, everyones happy, you get paid

considering its likely to be working in kitchens/bathrooms that are mostly not being replaced whilst using this method and the lighting is generally the only works being carried out

convince me, that will not ALWAYS be quicker, tidier and cheaper for everyone involved than re-boarding/(re-coving?), skimming and repainting a ceiling

your just making a load of hard work for yourself!
I never said skim the ceiling I said tape and joint. The average bathroom is just shy of 4 square meters....2.88 square meters to a plaster board.

Two sheets of board £14
Jointing tape £3
Dry wall screws £4
Filler £9
Paint £10

Total. £40

Filling the holes

Jointing tape £3
Dry wall screws £4
Filler £9
Paint £10

Total £ 26

What other mess are you going to make either way you still have to sand and paint and you’ve already banged a hole saw through multiple times creating dust?

Both going to take roughly the same time to do......So for £14 extra you have a superior finish. I know what I would choose in my own house.

Why would you need to come back?
 

Wilko

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Sorry but I don’t see it being cheaper and easier to give someone a new ceiling than repair
I never said skim the ceiling I said tape and joint. The average bathroom is just shy of 4 square meters....2.88 square meters to a plaster board.

Two sheets of board £14
Jointing tape £3
Dry wall screws £4
Filler £9
Paint £10

Total. £40

Filling the holes

Jointing tape £3
Dry wall screws £4
Filler £9
Paint £10

Total £ 26

What other mess are you going to make either way you still have to sand and paint and you’ve already banged a hole saw through multiple times creating dust?

Both going to take roughly the same time to do......So for £14 extra you have a superior finish. I know what I would choose in my own house.

Why would you need to come back?
Not to argue, but I can’t put up a board by myself and as we all know, I’ve got no mates ...
 

Midwest

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To repeat myself again, chose either method, whichever is appropriate. If I was doing a kitchen refurb for example, and other wiring was being altered, I'd remove a small section of board, mates or no mates. If was half dozen down lights, I'd cut circles.

Whatever, the client is responsible for making good to finish level, along with decorating, either taping & employing a plasterer or decorators etc.
 

Midwest

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@Sahibzada. You've been a trainee member for nearly 3 years, but your sole contribution, in all that time, is to give me a bed spelling rating. Jolly well done :p
 

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