How to Draw a Reflected Ceiling Plan

This blog post follows our earlier post titled Introduction to residential lighting: an architect’s guide. That article is an introduction to the different types of artificial lighting within a domestic setting, types of light fixtures, LEDs, light temperature, Lumens, lux, fittings and bulbs.

This post will go into more detail about how these light fittings and drawing symbols can be laid out in a reflected ceiling plan, what to include and how to draw a lighting layout. We will delve into the details on lighting position design considerations as well as exploring different lighting control options and how to position sockets and switches within a room.

You can download the reflected ceiling plan example, along with this PDF Guide at the end of this post. We have created a pack of symbols and trim details that will help you with your lighting layouts and reflected ceiling plans to accompany this post. We also have a large selection of electrical and lighting symbols available to purchase or free download for members. Scroll to the end for more information. 

[Scroll to the end of the page to download this article as a handy PDF guide]

01 Detail Library Lighting Key Cropped

The key feature of any architectural drawing is to convey information in the clearest way possible. This may mean that on some projects you can include more information than in others.

Basic principles

What is a reflected ceiling plan?

Lighting layouts are usually drawn as a reflected ceiling plan. This can sound very complicated but you do not need to do anything to your plans. A reflected ceiling plan is drawn over your normal plan. The word reflected is used as you are not representing the ceiling from below, as seen from inside the room, but from above. This way you can have the floor layout, furniture, sanitaryware, kitchen, doors and fitted furniture as reference. You do not need to mirror the floor plan.

02 Detail Library Reflected Ceiling Plan

Detail Library – Example reflected ceiling plan for a period semi-detached ground floor extension

In more complicated terms, a reflected ceiling plan is a plan of a ceiling that gets projected on a flat plane placed over the plan.

What items should be included?

The main things to include are any items that will need to be installed in the ceiling. It is also necessary to include any wall lights and lamps, so the lighting design can be viewed as a whole.

03 Detail Library Reflected Ceiling Plan Key

Detail Library – Example key with lighting types used within a reflected ceiling plan

In addition to the lighting, both in the ceiling, walls and floor, a reflected ceiling plan will include any other electrical equipments to be installed on the ceiling, such as:

  • speakers
  • security alarm and sensors
  • smoke alarms
  • carbon monoxide detectors 
  • heat detectors 
  • sprinklers
  • mechanical curtains and blinds
  • skylights
  • ceiling vents
  • mechanical extracts
  • inspection hatches 

and any other ceiling decorations such as cornices or rosettes.

Apart from the lighting and other ceiling elements, a lighting layout should show the circuits that the lights are on including the switch and its location. When a light switch is switched on, certain lights switch on, these are all connected and should be shown as such on the plan.

How is this drawn?

This is usually done with a curved line which goes from the controlling switch through all the lights that it controls. Sometimes, in large rooms or in spaces like corridors, you may have two switches that control the same circuit, so that you can switch lights on and off from different points of a room. To represent this, the curved line will go from one switch, to all the lights in that circuit and finish at the second switch. Confusingly, in some places it can be called a 3-way switch but in the UK it is more normally called a 2-way switch.

It is important to include dimensions and if lighting is centred on items, noting that a light string is of equal distance to for example the edge of a window or piece of fitted furniture. Guidelines on the drawing can sometimes help with this. 

Some people show reflected ceiling plans with colours to help differentiate between lights, circuits and heating, although this is not mandatory. Colours and style of electrical layout plans often vary from practice to practice.

Sometimes with smart lighting systems, a switch or control panel does not control a single circuit. For these representations, you may want to show the location of these control panels and what lights are linked, but you do not need to link lights to the switches as all lights when installed will be linked back to a control module which is then controlled through the control panels in each location or wirelessly. More information regarding this can be found below in the section Lighting controls.

04 Detail Library Reflected Ceiling Plan Print Lighting Layout

Detail Library – Simple front room lighting layout with a lamp position, two gang switch controlling a pendant and two spots in front of fitted furniture with a possible point for a carbon monoxide detector if installing a working fireplace.

Can any other information be included?

The key feature of any architectural drawing is to convey information in the clearest way possible. This may mean that on some projects you can include more information than in others. For this example, we have omitted heating and socket information for clarity. This information can then be overlaid onto the plan as a further Plumbing/Heating Layout and AV/Electrics. However, on some projects it is also feasible to include one reflected ceiling plan which can include all the m&e information such as:

  • Consumer unit
  • Door bell
  • Thermostats
  • Plug sockets
  • Fuse spurs
  • Isolation switches 
  • Aerial sockets
  • Data sockets
  • Telephone sockets
  • Master telephone/data entry socket or point
  • USB sockets
  • Speaker sockets
  • Gas meter
  • Gas connection points such as a boiler, cooker and fireplace
  • Radiator position
  • Heating manifold
  • Boiler location
  • Areas of wet and/or electric underfloor heating

Within the viewport it can sometimes be useful to grey certain layers or switch off certain elements for clarity. Items to be greyed can include:

  • Fitted furniture
  • Loose furniture
  • Sanitaryware
  • Kitchen

Whereas information that is normally greyed out to represent things above the plan, such as skylights, should be drawn in a black line.

Lighting position design considerations

There are a number of key considerations when laying out lighting.

 

Rooflights

The position of skylights and their structure can interfere with the position of lighting in the ceiling. It can be helpful to start laying out the lighting and any skylights from the start of a project as the size and position of the skylight may need to change if artificial light is needed under a proposed skylight position. A reflected ceiling plan can help to juggle the two. Surface mounted wall lights can also be used within the skylight ceiling recess to add artificial light to an area under a skylight. 

05 Downstand and rooflight

Ceiling shape and downstands

Especially within extensions, there can be areas of sloped ceilings, downstands and flat areas of ceilings. All of these can add complexity to a lighting layout. Drawing all of these details on a reflected ceiling plan can assist in laying out artificial lighting and any other ceiling elements. 

Existing and proposed ceiling decorations

It is important to consider these elements such as cornicing and ceiling roses as they may push ceiling lighting into other positions so that it does not interfere with this decoration. 

Window positions

It can sometimes be desired to line up lighting with windows.

Furniture layout

Where you place lighting in terms of furniture is key, especially any fitted furniture. Task light may be required above a kitchen counter, you may want accent lighting over a dining table, you may want to avoid bright spots over soft furnishings such as sofas and chairs.

 

There are many other considerations based on each specific project and client. Some of the following considerations are further discussed in the previous post Introduction to Residential Lighting: An architect’s Guide:

  • Task required for a space
  • Type of light fitting
  • Diffusion of light fitting

 

Lighting controls

Analogue lighting controls are those we are most accustomed to. These are usually in the form of a switch, controlling a light circuit to be on or off. This can become complicated if you are trying to create different lighting circuits in a space or if you require a circuit to be controlled from two sides of a room. Within a residential setting, analogue controls should be kept as simple as possible. Having one to two circuits in a room with ambient lighting and accent lighting controlled from one double switch whilst having any task lighting controlled at the location of the task can help usability of a space. Having too many circuits for a space with switches in different locations of a room can mean the user has to travel to switch on a certain section to switch off another. In a large space like an extension, three circuits may be necessary, although it may be better to group them in zones rather than types. The zones may be the kitchen, dining area and background lighting for example.  

Dimmers are a great way of increasing the control of a circuit. This type of switch allows for the lights to be turned on or off and also can provide low ambient light or medium light depending on the use of a space. Traditionally a dimmer would regulate the current in a circuit, allowing more current would give a brighter light and restricting the current would reduce the brightness of the bulbs. However, LEDs work with very low currents and therefore when pairing dimmers it is important to check if the bulbs themselves are dimmable. An LED compatible dimmer switch and circuit is also required. This process can be very difficult if trying to combine different types of lights into one circuit and can cause flickering if not done correctly. 

06 Detail Library Reflected Ceiling Plan Lighting Layout

Detail Library – Image showing a two gang switch with a one-way and two-way circuit connecting to a pendant light with a coloured curved line

Digital lighting control can be used to set up different scenes or moods in spaces. Rather than having all the lights on a switch or dimmer, a control panel is installed so all lights, ambient, task and accent lighting can be controlled at once. This could include settings such as morning, when some task lights or low ambient lighting is required, entertaining, when ambient lighting and accent lighting might be needed, or nightlight when only low ambient or low accent light is required to use the spaces. Examples of these systems include DALI, DSI and KNX based systems. These can also be integrated with mechanical controls such as those for electric blinds, mechanical window openings, sound systems, thermostats, etc. 

Wireless lighting controls are becoming more of a popular solution as they do not require a hardwired control panel to all the light fittings. They are usually controlled via a tablet or mobile phone app and require the use of special bulbs or fittings that communicate. These can be very useful in retrofit projects although they require the use of one brand’s hardware and do not tend to work with other mechanical items like thermostats. 

Other lighting controls are those which are activated through motion. These are usually hardwired in and used locally for accent lighting or in bathrooms. A common application is cupboard lighting when a door is opened to see the contents and switches off when the door is closed. These are also useful in bathrooms with no windows and switch on when the door is opening and someone enters. A timer can be set so that the light switches off after a certain amount of inactivity. These types of controls can be very useful within a garden setting.

Wall switch and socket location considerations

Having all switches at the same height and the same distance from door frames / architraves can really help elevate a simple project as well as making sure a home is accessible to all users. To communicate this to the construction team, a simple standard socket and switch layout can be produced. In a more detailed project, an elevation can be drawn for each room to show switch and socket positions to make sure that they do not clash with any furniture or that they are positioned perfectly for electrical items and use.

07 Detail Library Reflected Ceiling Plan Internal Elevation Switched and Sockets
08 Detail Library Reflected Ceiling Plan Internal Elevation Sockets Spacing

Detail Library – Image showing a two gang switch with a one-way and two-way circuit connecting to a pendant light with a coloured curved line

A socket layout can help show the location of sockets in relation to different items in a house, such as furniture, sanitaryware and kitchen items. Having an elevation as well as a plan, will make sure that electrical locations can be checked carefully on site. 

A socket layout can also include a summary table for each room of how many electrical items are in a room to help with costing for the electrician or building. This can include;

  • Name of the room
  • Power (how many sockets)
  • 5A (how many 5A sockets)
  • Data (How many data sockets)
  • TV (how many tv sockets)

Part M4(1)

When setting out switches and sockets, our first point of reference is the building regulations Part M4. 

Guidance within this document, titled Service and controls 1.18 recommends:

1.18 To assist people who have reduced reach, services and controls should comply with all the following.

  • Switches and sockets, including door bells, entry phones, light switches, power sockets, TV aerials and telephone jacks,serving habitable rooms throughout the dwelling have their centre line 450mm-1200mm above floor level, as shown in Diagram 1.5. 
  • Consumer units are mounted so that the switches are 1350-1450mm above floor level. 
09 Building Regulations Part M4(1) Height of switches sockets Diagram 1.5

Diagram 1.5 – Building Regulations Part M4(1) Heights of switches, sockets etc.

Another key element to consider is the height of the door handles. Well designed projects often align switches with the door handles usually about 1000-1050mm from ffl. When setting out distances between elements, a good rule of thumb is for switches and sockets to be abound 100mm-200mm from architraves or door frames and room corners respectively. Spacing between visible sockets and switch plates should be about 50mm. Depending on the location these can be stacked or placed side by side.

Summary

This post has looked at laying out residential lighting design both with a reflected ceiling plan and internal room elevations. We have looked at what items should and can be included in a reflected ceiling plan along with details on lighting position design considerations and how this should all be drawn. Socket and switch positions are also key in designing a cohesive lighting layout and following basic rules of thumb, along with the Building Regulation recommendation on accessible design can help to elevate a simple project. 

Download the Guide

29 How to Draw a Reflected Ceiling Plan - Resource

Get the Details

We have put together a pack of standard electrical and lighting symbols to drop into plans and simplify the lighting design process. 

04 Mar Lighting Detail Pack LR

Author

Written by Aida Rodriguez-Vega, architect and researcher. At the Detail Library, Aida keeps busy by carrying out technical research and drawing new details for the ever-growing library.