An interior designer shapes the physical structure, spatial planning and technical specification of an interior—walls, layouts, materials, lighting, systems—while a decorator works with surface finishes, colour, furniture and soft furnishings within an existing space. The designer solves problems; the decorator refines appearance. For structural change or commercial fit-out, you need a designer. For aesthetic refresh, either role works, but designers bring spatial expertise that prevents costly mistakes later.
What does an interior designer actually do?
An interior designer works with space itself. They plan room layout, specify wall and floor finishes, determine lighting strategy, select and position fixed elements like cabinetry and built-in storage, coordinate mechanical and electrical systems, and produce detailed specifications for manufacturers and contractors. Their role touches planning, building regulation, safety and functionality alongside aesthetics. When a commercial space needs reconfiguring—as with the Fruittii Hair Salon or Beaulieu Dental Practice—a designer manages the entire envelope: they decide where basins go, how traffic flows, what materials withstand daily use, and how light serves both safety and mood.
A designer’s output is a complete technical brief. They produce plans, schedules, material samples and installation drawings. Contractors and suppliers build from these documents. The designer’s competence is measured not by visual trends but by whether the space functions, lasts, and solves the client’s real problem. This is why designers typically hold professional qualifications, understand building standards, and carry liability insurance.
What does an interior decorator do?
A decorator works within a finished or near-finished interior. They select and arrange furniture, soft furnishings, artwork, lighting fixtures, colours and accessories. They understand proportion, colour theory, style, and how objects relate visually and spatially. A decorator can completely transform a room’s feeling without altering its bones. They source pieces, manage installation, and create cohesion across surfaces and objects.
Decoration is skilled work—it requires visual judgement and knowledge of materials, craftsmanship and sources. A good decorator prevents visual chaos and makes a space feel intentional. However, decoration works within constraints set by the designer or the existing structure. If the room layout is awkward, the ceiling too low, or the light poor, decoration alone cannot solve those problems.
When do you need a designer rather than a decorator?
You need a designer when the problem is spatial, structural or functional. This includes: new build or renovation where walls, floors and systems are being installed; commercial fit-outs with specific operational requirements; spaces where light, acoustics or flow are broken; any project requiring planning or building regulation sign-off; or interiors where the budget is substantial enough that poor spatial decisions become very expensive to correct later.
The London Embankment Apartment, Witham Project and Tone at Canary Wharf all required design—not decoration—because they involved layout planning, material specification, coordination with trades, and decisions about how people would actually move through and use the space. A designer entered at Discovery, developed a Concept, moved into Concept, Design & Specification with detailed drawings, then oversaw Commission and Reveal. At each stage, the brief was refined and technical problems solved before a single decorative choice was made.
If your space is already functional and finished, and you want it to feel different, a decorator may be sufficient. If you’re uncertain whether the space works, or if you’re making significant changes, a designer’s eye will catch problems that decoration cannot hide.
Can one person do both roles?
Yes. Many interior designers are skilled decorators, and some decorators have design training. However, the skill sets are distinct. A designer must understand space planning, technical specification, building systems and regulatory compliance. A decorator must have visual taste and sourcing knowledge. Few people excel equally at both, and the best practitioners often specialise.
What matters is whether the person you hire can demonstrate competence in the specific area your project needs. If you’re renovating a commercial salon or practice, evidence of previous design work—plans, material choices, how the space functions—is more relevant than portfolio images alone. If you’re refreshing a finished living room, show them similar decorative projects and ask how they’d approach colour and proportion in your exact space.
How to choose: what questions to ask
First, define what your space needs. Does it need to be reconfigured, or does it need to feel different? If layout, light, storage or traffic flow are the problem, you need a designer. If the space functions but feels tired, a decorator may be the answer—though a designer’s eye can always improve it further.
Second, ask to see relevant previous work. For a designer, request projects in your sector or building type. A dental practice designer should show dental work; an estate agent office should show commercial retail or office fit-outs like Keystones Estate Agent. For a decorator, look for colour and material choices in spaces similar to yours. Ask how they sourced pieces, managed timelines, and what they’d do differently if they repeated the project.
Third, understand the process. A designer should describe their process—Discovery, Concept, Concept, Design & Specification, Commission, Reveal—and explain what happens at each stage and what decisions get made when. This transparency shows whether they’ll catch problems early (when they’re cheap to fix) or late (when they’re expensive). A decorator should walk you through sourcing, mood boards, and installation sequencing.
Why the distinction matters in practice
Conflating the two roles often leads to disappointed clients. Someone hired as a ‘decorator’ cannot fix a poorly planned space; someone hired as a ‘designer’ who lacks decoration knowledge may produce a technically correct but visually cold interior. The clearer the brief and the clearer the role, the more likely the result will satisfy you.
The most durable interiors—residential and commercial—come from projects where design and decoration are both present and intentional. A competent designer creates a foundation that will serve the space for years. A skilled decorator makes that foundation feel like home or a workplace people enjoy. Understanding which role your space needs, and selecting someone genuinely skilled in that role, is the first and most important decision you’ll make.