7 Principles of Universal Design

These principles were developed in 1997 by a team of architects, designers, and disability advocates at North Carolina State University. They remain the most useful framework for making inclusive design decisions.

1. Equitable use

This means the design works for everyone without separating people. One entrance that everyone uses, rather than a main door for most people and a side ramp for wheelchair users.

2. Flexibility in use

Flexibility in use means the design should accommodate different people with varying abilities. A worktop at an adjustable height that works for someone seated and someone standing. A lever door handle that works for someone carrying heavy bags, someone with a limited grip, and someone who has a prosthetic hand.

3. Simple and intuitive use

This means that space is easy to navigate without needing to think too hard about movement within it. Clear sightlines, logical layouts, and consistent signage all help. If a space needs instructions to use it, then it has not been designed properly.

4. Perceptible information

This means hazards and cues are communicated in more than one way. For example, a step that changes in both colour and floor texture warns someone with limited vision just as effectively as it warns someone with full sight.

5. Tolerance for error

It means the design reduces the consequences of mistakes. Rounded corners instead of sharp edges, non-slip flooring in wet areas, and lever taps that cannot scald all reflect this principle.

6. Low physical effort

Low physical effort means the interior space is comfortable to use without unnecessary strain. For example, easy-opening doors, storage at reachable heights, and light switches that do not require a stretch all make a difference across a day of normal use.

7. Size and space for approach and use

This means that there is enough room for everyone to reach and operate the space, regardless of body size or mobility aid. A 900mm doorway accommodates a standard wheelchair, and a 1500mm clear floor area allows a wheelchair user to turn around with ease. These are not special requirements; they are simply sensible baselines.

Where Universal Design Shows Up in Interior Design Practice

Floor level changes are one of the most common barriers in both homes and commercial spaces. A single step at an entrance, a raised threshold between rooms, or a sunken living area creates difficulty for anyone using a wheelchair, a walking frame, or a pushchair. Level transitions between floor surfaces solve this without any visual compromise.

Door widths matter more than most clients realise until they need to use them. Older properties have interior doors too narrow for comfortable wheelchair access. Getting this right at the design stage costs nothing but changing it later becomes expensive.

Lighting levels with contrast abilities benefit everyone. Higher light levels reduce trip hazards and make everyday tasks easier, while stronger contrast between walls, floors, and furniture helps anyone with reduced vision move through a space effortlessly.

Kitchens and bathrooms offer the most direct opportunities to apply universal design thinking. Varied worktop heights, knee clearance under surfaces, pull-out storage, and lever or sensor taps, rather than twist faucet handles, all make space work better for a wider range of people. Most of these decisions add no cost at all when they are made at the design stage, rather than when they are retrofitted later.

Designing for Life

A useful way to explain universal design to a client is through the idea of a lifetime home, a space designed to remain comfortable and functional as the occupant gets older, rather than needing to be modified at every stage of life. A young, fit client may not immediately see why wider doorways matter, but a professional designer who can show them how those decisions protect the long-term value and usability of their home is giving them something genuinely useful.

Universal design is not about designing for disability but about designing for the full range of human experience: childhood, old age, injury, illness, and the enormous variety in how different people move through the world.

Spaces that work for that range are simply better interior spaces.​​​​​​​​​​​​​​​​