where to position downlights

[petedel]

Im planning on removing two lighting points from my living room ceiling and replacing with 8 230v downlights (2rows of 4).

the room is 3.6m x 5.0m

In order to get the best use out of these would it be best to divide the ceiling into 8 imaginary sections an then use each centre as the new lighting point or divide the length by 5 and place at every metre and same for the width ( 3.6/3 so lights placed 1.2m apart?

ceiling/floor space is accessable from above and doesn't have any insulation inside

before anyone asks I have 2330 level 3 and 17th edition, I also have access to a metril mft that has a valid calibration certificate

 

[Octopus]

Out of interest how to plan to get "past" the joists?

My question above was aimed at the OP - most DIYers haven't thought about how the lights get linked together!

 

[AndrewMgan1976]

Out of interest how to plan to get "past" the joists?

Do we not just use magic???

I installed 10 downlights in a kitchen yesterday, had to cut an extra 11 holes to get 'past' the joists

 

[mikeyb1000]

Joists - DO NOT cut into them you will find this is against reg you can only take out a notch or drill through - even with this restrictions apply so i doubt very much that you can straight up take a starett to it and cut into it. Lightly score the circle with the starett into the ceiling and drill a 5mm bit all the way into ceiling at each four "corners" and see if you hit a joist. If not - happy days. If so, then you what I usually do is score again to the left or right of the first circle by one radius - place the arbour bit at the circles edge and then score in again. Again repeat process of drilling in with the 5mm bit until you detect no joist. Okay you may have to polyfill a few scores but this is better than putting whole cut off plaster circles back in the holes. Subsequently if one cut out has to be realigned to avoid a joist then all downligjts on that row will need to be synchronized to do the same and offset by same amount to keep symmetry. From my experience stud finders are ****e.

 

[D Skelton]

We usually cut the bit of the joist out that is in the way. A quick nip tuck with the recip, job's a gooden!

Joists - DO NOT cut into them

Just thought I'd make very clear that my previous post was a JOKE!

Of course we don't cut joists out lol, that would be madness!

 

[Badged01]

Just thought I'd make very clear that my previous post was a JOKE! Of course we don't cut joists out lol, that would be madness!

Now you tell me!!! Was wondering why that kitchen ceiling fell down on me this morning ......

 

[Adam W]

Now you tell me!!! Was wondering why that kitchen ceiling fell down on me this morning ......

It wouldn't have happened if you had known what you were doing, I hope you were adequately insured!


I am aware that your last post was a joke. Mine was as well, just so as to avoid any further confusion.

 

[MDJ]

Im planning on removing two lighting points from my living room ceiling and replacing with 8 230v downlights (2rows of 4).

the room is 3.6m x 5.0m

In order to get the best use out of these would it be best to divide the ceiling into 8 imaginary sections an then use each centre as the new lighting point or divide the length by 5 and place at every metre and same for the width ( 3.6/3 so lights placed 1.2m apart?

ceiling/floor space is accessable from above and doesn't have any insulation inside

before anyone asks I have 2330 level 3 and 17th edition, I also have access to a metril mft that has a valid calibration certificate

If the lights are in rows of 4 then measure the room and divide by 5, that will give you an idea of 4 equal spaces to look at, and 2 wide divide by 3 for the 2 rows. You can then mark the ceiling with a pencil where each divide is and stand and look at them to decide if the positions look right or not. You can then move them either way a few inches or so until it looks right. Then you have the problem with joists being in the way LOL, all part of the fun though.

 

[7029 dave]

In the ceiling everybody knows that.

 

[petedel]

My question above was aimed at the OP - most DIYers haven't thought about how the lights get linked together!

16mm drill bit straight through centre of joist

 

[petedel]

If the lights are in rows of 4 then measure the room and divide by 5, that will give you an idea of 4 equal spaces to look at, and 2 wide divide by 3 for the 2 rows. You can then mark the ceiling with a pencil where each divide is and stand and look at them to decide if the positions look right or not. You can then move them either way a few inches or so until it looks right. Then you have the problem with joists being in the way LOL, all part of the fun though.

that's how I was trying to explain it when I said about dividing ceiling into sections and placing the lights in the centre of each, decided on just 6 lights instead as 4 in a row looked too crowded when I drew it 3x2 gives a more even space

 

[telectrix]

my method for ensuring i'm not too close to a joist ( assuming i can't locate them,) wire coat hanger angle with about 4" to go up the hole. then with the wire in , spin it round. if it goes full circle then there's no joist and then cut hole.

 

[Octopus]

my method for ensuring i'm not too close to a joist ( assuming i can't locate them,) wire coat hanger angle with about 4" to go up the hole. then with the wire in , spin it round. if it goes full circle then there's no joist and then cut hole.

I do that using a single core of 2.5mm! Great minds think alike, but I also make sure that no only is there the diameter available, but also the height!

 

[petedel]

another method ive used to find joists is use one hand to push up against the ceiling and tap with a small flatblade screwdriver with the other hand. instead of a hollow sound it becomes louder when tapping against a joist. I know it wont find pipes or cables, ill only find them when the floorboards come off upstairs

 

[Dave 85]

If the lights are in rows of 4 then measure the room and divide by 5, that will give you an idea of 4 equal spaces to look at, and 2 wide divide by 3 for the 2 rows. You can then mark the ceiling with a pencil where each divide is and stand and look at them to decide if the positions look right or not. You can then move them either way a few inches or so until it looks right. Then you have the problem with joists being in the way LOL, all part of the fun though.

Sorry dude but this is just plain wrong. This stuff is basic, it baffles me the number of electricians who cant do lighting plans.
To get the most even spread of light throughout the room you want:
(example)
wall-1.25m-light-2.5m-light-2.5m-light-2.5m-light-1.25m-wall
or
wall-0.6m-light-1.2m-light-0.6m-wall
etc etc
As for avoiding joists....it's an artform.
I mark the ideal positions, draw round the holesaw, spike the centre and 4 points round the edge on all lights to check for joists before cutting any holes. If one light needs to be moved I will generally attempt to move any others necessary to maintain even spacing. It can take time.

To get past joists, with no top access, I just notch 3" by 1" out of the plasterboard under each joist, clip the cable to the underside of the joist and then....
A. Tell them to call a plasterer
or
B. Wedge folded up down lighter instructions in the hole either side of the joist and slap some one strike filler over it. (I don't claim to be a good decorator)

 

[MDJ]

It has always worked for me Dave, it is a guide to start then easy to confirm actual final positions, I have only fitted thousands and have lots of happy customers. That said I wouldn't say your measuring method is wrong at all, every room has it's difference and sometimes you may find your measuring guide won't work.