Marking out positions for recessed downlights in a room

[HawkEye244]

Hi all,
I want to do the marking out and intend to use a padsaw or holesaw from below to make the cuts for the downlights I've got planned to fit. I've never done this before and this is how I am planning to approach the job. Let me know if it's totally out of sync, or totally wrong.

1) Use a chalk line and snap diagonally from corner to corner.
2) Measure in equidistant, e.g. 1.5metres from the corner of each line and mark on ceiling.
3) Adjust sizes where necessary to account for any joists above (using bradawl)
4) Apply same procedure to all rooms.

Common sense would say not to measure off any of the walls as this could cause very odd positions for the lights but I'm not sure?

None of the rooms are big enough to need more than 4 and if I do go for a greedy 5, the 5th will be fitted centrally and the other for will be offset slightly less from each corner to account for the extra lux. 6 lights could obviously be marked using the same process if super greedy.

Appreciate your thoughts, good and bad?
Many thanks

 

[EFLImpudence]

Firstly you need to determine where the joists are, then allow a certain distance from them to work out your pattern.

Then buy some decent lights which don't need holes in the ceiling instead .

 

[sparkwright]

As said, work out where the joists are FIRST.

Chalkline - excellent, wish more people used them.

Use a holesaw, NOT a padsaw, to cut out the holes.

But before you do this, you a thin long screwdriver or a bradawl before drilling the holes, to check joists or other obstructions aren't in the way.

Before drilling the holes, test with the bradawl in the centre, and then all four 'corners' (wrong word) of the circular hole, to be sure you are clear of the joists etc.

Nothing wrong with measuring from the wall, assuming the wall in out of true.