The interior design guide
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The interior design guide. A definitive knowledge base for interior designers.

From first principles to the finishing touches: shell, surfaces, space planning, furniture, electrics, plumbing and joinery, in the order a project runs.

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The Lexicon.

Every term, in plain words.

From hue and light reflectance to bonding and kick space, every term the guide uses has a short definition, what to know in practice and the pages that use it.

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The interior design guide.

A definitive knowledge base for interior designers.

Eleven chapters take a home from first principles to the moment you show it to the client. Start with Foundations and read in order, or search for a topic, a term or a rule of thumb.

Chapters.

Eleven steps, from principles to presentation.

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Where to go next.

Sections.

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Where to go next.

Surface types and properties,

the right material, in the right place.

Floors, walls and ceilings do different jobs and wear in different ways. A timber floor must withstand footsteps, a bathroom wall moisture, a kitchen splashback constant cleaning. The same material can suit one place and be entirely wrong in another.

Anatomy of a surface.

Substrate and finish.

A useful distinction is between the substrate, the construction a finish is attached to, and the surface finish, the visible and exposed layer. A ceramic tile may be laid over a screed, bonded to a prepared wall or set on a waterproofed assembly: the visible tile is identical, while the construction beneath it differs considerably.

The same five roles in every surface: structure, substrate, an intermediate layer, a fixing, and the finish you see.

The three surfaces of a room.

Floors, walls and ceilings.

Each surface, in turn, with the performance it is chosen for.

Floors

Floors receive the most continuous physical use. They carry furniture and foot traffic, resist abrasion, and shape the room’s acoustic and thermal comfort, while setting its visual base across its largest plane.

Hard floors such as tile, stone, polished concrete and timber are durable and easy to detail, but differ in sound, warmth and upkeep. Carpet and resilient floors are softer underfoot and reduce impact noise. Choose for traffic, moisture, cleaning, slip resistance, the substrate and the expected service life.

Walls

Walls are boundaries and backgrounds. Their finishes can be decorative, such as paint or wallpaper, or protective, such as tile behind a sink or durable panelling in a corridor.

Choose a wall finish by its exposure. A dry bedroom wall may need only painted plaster; a shower needs a properly designed waterproof assembly. In busy interiors, impact resistance and repairability matter as much as colour or texture.

Ceilings

Ceilings shape a room’s perceived height and carry lighting, ventilation and other services. They also control reflected light and reverberation.

Painted plasterboard, exposed soffits, timber linings, acoustic panels and suspended systems all differ in appearance, in access to the services above, and in how recessed fittings can be built in.

The main surface materials.

Their appearance is rarely enough.

Materials differ in composition, installation, physical behaviour and maintenance. The cube places each one by where it goes, whether it suits wet areas and how much upkeep it asks for; the table then sets out what each gives and what it demands.

Twelve material families placed by where they go, how they take water and the upkeep they ask for. Drag to turn the cube; choose a material to read its properties.

A general guide to each material family. The product chosen, and the complete assembly it is installed in, decide what it can do.

MaterialCommon applicationsMain qualitiesMain considerations
Solid timberFloors, wall liningsWarmth, natural variation, repairabilityMovement with moisture, wear, maintenance
Engineered timberFloors, wall liningsMore stable than comparable solid timberProduct construction, moisture limits, refinishing capacity
Ceramic and porcelain tileFloors, wet-area wallsHard-wearing, water-resistant surface, easy cleaningGrout, slip resistance, substrate and waterproofing
Natural stoneFloors, walls, worktopsDistinctive appearance, longevityPorosity, staining, sealing and maintenance
TerrazzoFloors, wallsDurable decorative surface, varied aggregateWeight, cost, joints, installation
ConcreteFloors, exposed structureContinuous mineral appearance, durabilityCracking, staining, surface treatment
Vinyl and resilient flooringFloorsComfortable underfoot, easy cleaning, wide range of looksSubstrate preparation, wear layers, product emissions
CarpetFloorsSoftness, thermal comfort, sound absorptionStaining, cleaning, wear and moisture
PaintWalls, ceilings, joineryVersatile, economical, easily renewedPreparation, sheen, cleanability and substrate
Wallpaper and wallcoveringsWallsPattern, texture, visual varietyMoisture, adhesion, visible seams, repairability
Plaster and decorative rendersWalls, ceilingsSeamless or textured appearancePreparation, cracking, specialist workmanship
Laminate and decorative panelsWalls, joineryConsistent appearance, durable facesEdge treatment, substrate, moisture

How to compare materials.

Several properties, judged separately.

Durability

Durability is a surface’s capacity to withstand its intended use over time. A bedroom, a busy restaurant and a public corridor may need different levels of performance from finishes that look alike.

Look for evidence that suits the material: abrasion and indentation resistance, impact performance, colour stability and the upkeep it needs. A hard surface is not necessarily scratch-resistant, and an expensive one is not automatically durable.

Moisture resistance

Some materials tolerate occasional splashes but fail in sustained wet conditions; others resist water themselves yet still need a waterproof assembly beneath them.

A porcelain tile is generally water-resistant, but tile and grout alone do not make a waterproof shower. The complete installation, with its waterproofing, penetrations, corners and drainage, has to be designed.

Slip resistance

Slip resistance matters most on floors exposed to water, grease or the outdoors. It depends on the surface finish, contamination, footwear and the test method.

Specify the slip-resistance classification required, or appropriate, for the jurisdiction and the use. A description such as anti-slip is not enough for a specification.

Acoustic comfort

Hard surfaces reflect sound; porous and soft ones absorb more. Carpet also reduces impact sound from footsteps, where a hard floor may need an acoustic underlay or another treatment in the floor build-up.

Surface absorption, impact sound reduction and sound insulation between rooms are three different properties: do not confuse them.

Maintenance and repairability

Consider how a material will age. Some gain an acceptable patina; others show scratches, stains or discolouring that a client may not accept.

Ask whether the surface can be cleaned, repaired locally, refinished or replaced without disturbing a large area around it, and with the cleaning products likely to be used in practice.

Environmental performance

Manufacture, transport, service life, indoor emissions, maintenance and what happens at the end of its life all count.

Product-specific Environmental Product Declarations (EPDs) and other verified disclosures help compare products, provided their scope and assumptions are compatible.

Four floor finishes, compared in words rather than scores. Product specifications and the complete assembly decide actual performance.

Choosing surfaces by room.

Start from what each room demands.

Identify each room’s demands before choosing a material. These are design priorities, not product approvals: check any finish against its technical data and the project’s requirements.

A small flat, each room shaded by what its surfaces must do.
RoomFloor prioritiesWall prioritiesCeiling priorities
Living roomComfort, wear, visual continuityAppearance, impact resistanceLight reflection, acoustics
BedroomWarmth, softness, low noiseAppearance, easy maintenanceCalm appearance, lighting integration
KitchenCleaning, spills, wearCleanable splash zonesMoisture tolerance, lighting
BathroomSlip resistance when wet, waterproof assemblyWaterproofing in wet zones, cleaningHumidity resistance, ventilation
HallwayAbrasion, dirt, repeated trafficScuff resistanceDurability, lighting
OfficeChair movement, acoustics, maintenanceImpact resistance, visual comfortAcoustic treatment, services
Commercial circulationIntensive traffic, cleaning, safetyImpact resistance, maintenanceAccess to services, fire and acoustic requirements

Checklist.

Before you choose.

Go through the list for each surface, room by room. Your ticks are kept in this browser.

Surface selection

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Where to go next.

Previous

3 · Surfaces

Next

Surface layout and transitions

Units