There is a moment on every renovation when the lighting stops being a matter of taste and becomes a matter of concrete. It arrives earlier than almost anyone expects, and it passes quietly. The electrician has the drawings, the walls are open, the ceilings are down, and for about a fortnight every decision about where light will come from in this house is cheap and reversible. After that fortnight, most of them are neither.
Ask a designer what went wrong on a project where the lighting disappointed and the answer is rarely that somebody chose the wrong fitting. It is almost always that a decision was made late. The scheme was resolved after the point at which resolving it cost nothing, and everything downstream became a compromise dressed up as a preference.
The programme is the brief
A lighting scheme has two calendars running against it. One is the design calendar, which is about how the rooms will feel. The other is the build programme, which is about first fix, plaster, second fix and completion, and which does not care how anyone feels.
The second calendar is the one that governs. First fix is the deadline for every cable, every drop position, every switch drop and every transformer location. Once plaster is on, moving a pendant position by four hundred millimetres means opening a ceiling, and on a project with any pace to it that conversation ends with somebody accepting the position as built.
Which means the lighting design has to be substantially finished before the trades that follow it arrive. Not sketched. Finished, to the point of a drawing an electrician can set out from.
What actually goes in the plan
A lighting plan worth the name is a reflected ceiling plan, which is to say a view looking up, showing every light position dimensioned from fixed points that will still exist when the walls are finished. Corner of a structural opening, centre line of a window reveal, edge of a chimney breast. Dimensioning from a wall that is about to be dry-lined is a classic and avoidable error, since that wall is going to move by fifty millimetres or so and take the setting-out with it.
Alongside it sits a schedule listing every fitting, its lamp, its colour temperature, its output, its finish and its control method. Then a switching and circuit layout showing which fittings are grouped together and what each control does. Then, on any project of size, elevations for the wall lights, because a wall light is set out in two dimensions and a plan only gives you one.
The schedule matters more than it looks. Colour temperature in particular has to be decided across the whole house at once rather than room by room, because inconsistency reads instantly and it cannot be fixed afterwards without rebuying lamps. We have written about what happens when this goes wrong, and it is one of the few lighting mistakes visible to people with no interest in lighting.
Control is the decision everyone defers
Dimming and switching get pushed to the end because they feel technical and detachable. They are neither. The dimming method dictates the driver inside the fitting, the dimmer at the wall and in some cases the cabling between them, all of which is first-fix work.
Deciding the control system late is how a house ends up with fittings that buzz, that flicker at the bottom of the range, or that will not dim below thirty per cent. Those faults are almost never the fault of the light. They are a mismatch between three components chosen by three different people at three different times. The compatibility problem is worth understanding in detail before it is delegated.
Where the budget sits, and why it decides the outcome
This is the part that does not appear in the design literature, and it determines more schemes than any drawing does.
On many projects the decorative lighting allowance ends up inside the main contract, held by the contractor as a provisional sum. When it sits there, the contractor carries both the risk and the benefit of what gets bought, and there is a standing incentive to substitute. A specified piece becomes an equivalent, the equivalent is cheaper, the difference is margin, and the client is shown the substitution late and in a context where refusing it costs programme.
Designers who have been through this once tend not to let it happen twice. The decorative lighting is carved out of the main contract and bought directly by the client, or by the studio on the client's behalf, with the contractor responsible for installation only. That single structural decision protects the specification more reliably than any amount of insistence at the drawing stage.
It has a second benefit. Buying direct means the long-lead pieces can be ordered against the programme rather than against the contractor's cashflow, which is the difference between a piece arriving for completion and arriving two months after the client moved in.
Ordering against the programme
Anything made to order needs to be treated as a long-lead item and placed on the procurement schedule alongside the joinery and the stone, not alongside the accessories. Eight to twelve weeks is normal for made-to-order decorative lighting, and it starts when the order is placed, not when the room is ready.
The practical rule is to order the made pieces at the point the ceiling design is fixed. That is usually months before anyone would instinctively buy a light, and it is the only way the piece is on site when the scaffold and the access equipment are still there, which is a saving in itself.
The rules of thumb, briefly
A designer researching this will meet a lot of numbered rules. The three-lighting rule, the five-seven rule, the correct angle to aim an accent light. They circulate widely and they are worth exactly what rules of thumb are usually worth, which is a starting point when you have no other information and nothing at all once you have measured the room.
The principle underneath them is sound and does not need a number. Light should come from more than one height and more than one direction. Anything aimed at an object should be angled so that neither the glare nor the viewer's own shadow lands where the viewer stands. Beyond that, the room decides. The layering framework in our working reference is more use than any of the numbered rules, because it forces a decision about each layer rather than offering a ratio.
The last week, which is not a formality
The final stage is commissioning, and it is skipped more often than it is done. Every adjustable fitting is aimed, at night, in the finished room, with the furniture and the art in place. Every dimmer is set and its scenes recorded. Lamps that have been swapped by somebody during the build are checked back against the schedule.
An hour of this transforms a scheme. It is also the only point at which the designer sees what they actually specified, which is a good enough reason to be there for it.
Where to start
If a project is at concept stage, the lighting conversation belongs there rather than at the point of choosing pieces. The questions are simple and they are structural. What is the ceiling doing, what will it carry, where can cable go, who is holding the budget, and what is on the critical path.
Our design team works with studios and specifiers at that stage, before the pieces are chosen and while the answers are still cheap. Start a conversation.
Words by Frances Ellory