Downlight advice - joists / spacing guide

[snipersmith87]

What are people's methods of installing downlights?? Rule of thumbs?? Spacing?? I installed 14 today in a kitchen. 2 banks of 7 at just over a metre apart. 650mm from walls. Problem is joists. felt like it took an eternity just to mark out as I would inevitably land on joists somewhere along my row then knocking out measurements. I didn't want to start pushing some 50mm forwards or backwards as wanted them all equal. I managed it but had to keep amending accordingly. Any advice on speeding things up appreciated!!!

 

[Octopus]

There are times when you have to compromise on spacing ........

Did you have all 14 on 1 switch?

 

[snipersmith87]

It was a open plan kitchen/diner but the customer is serious OCD and insisted he wanted them all evenly spaced as 2 rows. 2g switch 10 and 4. I used a laser to ensure straight but marking between lights was a nightmare.

 

[sam400]

Yea it's a nightmare, sometimes it works out sometimes it doesn't!
Hopefully your next one is easier - You will get quicker !
I had one recently where they had a massive roof lantern so all the surrounding timberwork was double or even tripled up, there was more wood than space to put lights took me forever to lay out!
I prefer a chalk line, only use a laser when the ceiling is painted also need a good quality tape that doesn't keep bending - fatmax XL for me!

 

[Leesparkykent]

Joists are generally 400mm or 6oomm apart. Your 1st row was 650mm from the wall and a meter apart. 650, 1650, 2650, 3650, 4650,5650,6650 So if they were 400mm centres you would hit 3 joists out of 7 lights.

 

[123]

You won't see a 50-100mm difference in spacings between downlights imho. Well unless they are out of line of course

 

[littlespark]

I dont think there is a way to speed it up... The joists may not be equally spaced, or not a 'standard' distance apart. You can only check, measure, check again.... Sketch a plan, see what it looks like..
Watch out for wood crossing the space between the joists too!

 

[Octopus]

Or you may get lucky and find you a placing lights in a consistent gap between 2 joists .....

 

[snipersmith87]

Joists are generally 400mm or 6oomm apart. Your 1st row was 650mm from the wall and a meter apart. 650, 1650, 2650, 3650, 4650,5650,6650 So if they were 400mm centres you would hit 4 joists out of 7 lights.[/QUOTE

They was 1100 apart. The joists also changed direction on the last 4.

 

[snipersmith87]

I dont think there is a way to speed it up... The joists may not be equally spaced, or not a 'standard' distance apart. You can only check, measure, check again.... Sketch a plan, see what it looks like..
Watch out for wood crossing the space between the joists too!

Perhaps I'm looking into it too much. Just took forever just to get set measurements to miss joists consistently. I suppose give or take 50mm when landing on a joist isn't the end of the world. Just nice to get everything evenly spaced.

 

[snipersmith87]

Do you guys normally measure end lights first and then space within??

 

[Leesparkykent]

1100mm apart...That's really surprising. I've never seen joists that far apart before. I can't see how at them distances how it would be structurally sound and must of been a complete ball ache to board as sheets come in 2400mmx1200mm size so when the joists are laid out in either 400mm or 600mm centres then the board finishes on the centre of a joist.

 

[snipersmith87]

1100mm apart...That's really surprising. I've never seen joists that far apart before. I can't see how at them distances how it would be structurally sound and must of been a complete ball ache to board as sheets come in 2400mmx1200mm size so when the joists are laid out in either 400mm or 600mm centres then the board finishes on the centre of a joist.

Apologies mate. The downlights were spaced at 1100mm.

 

[Leesparkykent]

I whip the boards up above as you need them up any way, measure joists and jot them on a bit of paper, work out positions as not to hit joists, mark them on ceiling, Bradawl the ceiling where I've marked them to double check
I haven't hit anything then cut them out.

 

[Octopus]

^^ a bit tricky if it's a tiled bathroom floor!