Downlight centres and wall offsetsA ceiling grid should be read with the task surface and first-row offsets before holes or rows are fixed.

Table PDFDownlight Set-Out Planning Table

Download the table with the page URL and retrieval date for offline lighting checks.

Set-out item	Value to list	Planning check	Boundary
Room outline	Room length, width, ceiling shape and fixed obstructions.	Confirms the grid is based on the same area as the downlight count.	A simple rectangle should not hide bulkheads, beams or cupboards.
Effective height	Ceiling height minus the assessed plane height.	Links beam diameter and spacing to the surface being lit.	Floor, desk and bench checks can have different effective heights.
Beam and output	Beam angle, delivered lumens and fitting trim or diffuser note.	Shows whether spacing is being checked for spread, output or both.	A wide beam does not remove the need for glare and task-position checks.
Row centres	Proposed spacing between rows and between fittings in each row.	Keeps actual centres beside the calculator or chart result.	Average spacing can still shift for symmetry and ceiling services.
Edge offset	Distance from walls, benches, wardrobes, curtains or tall furniture.	Helps avoid weak edges, wall scallops and shadowed task surfaces.	Edge notes do not replace detailed set-out drawings.
Task and view notes	Bench, desk, mirror, screen or seating positions that affect glare or shadows.	Keeps the lighting layout tied to where people stand, sit or work.	A uniform grid can still perform poorly at a named task surface.

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