Interior Designer vs. Architect: Who Does What During a Renovation or New Build?

An architect and an interior designer contribute different but complementary expertise to a major home renovation. In general, the architect focuses on the building’s structure, exterior form, code requirements and architectural planning, while the interior designer focuses on how the interior functions, feels and comes together in detail.

For complex renovations, additions and custom homes, homeowners often benefit from having both professionals involved. The strongest results typically come when the architect and interior designer collaborate early, before the plans and major interior decisions have been finalized.

What Does an Architect Do?

An architect considers the building as a whole. Depending on the project and agreement, the architect’s work may include:

• Assessing the existing building

• Developing the overall architectural concept

• Planning additions or significant structural changes

• Creating floor plans and exterior elevations

• Addressing zoning, code and permit requirements

• Coordinating structural and other engineering consultants

• Preparing architectural construction drawings

• Assisting with permit submissions

• Reviewing construction in relation to the architectural documents

  
  

The architect’s scope is especially important when a project involves changes to the building’s structure, exterior envelope, footprint, stairs, windows, roof or relationship to the site. An architect may also contribute to interior layouts and architectural details. The exact scope varies by firm and should be confirmed before the project begins.

What Does an Interior Designer Do?

An interior designer considers how the home will function and feel from the inside. Depending on the project, the interior designer’s work may include:

• Reviewing and refining interior floor plans

• Developing furniture and circulation layouts

• Designing kitchens and bathrooms

• Designing custom cabinetry and millwork

• Planning storage throughout the home

• Developing interior elevations and details

• Selecting flooring, stone, tile and other finishes

• Selecting plumbing fixtures, appliances and hardware

• Contributing to lighting and electrical planning

• Selecting or designing furniture

• Developing window treatments

• Selecting rugs, textiles, artwork and accessories

• Coordinating final installation

The interior designer looks at how these decisions relate to one another across the complete home. A kitchen layout affects lighting, plumbing and circulation. Furniture placement affects electrical outlets and architectural openings. Millwork influences wall dimensions, ceiling conditions and finish transitions. Addressing these relationships early helps connect the architectural plan to everyday living.

Where Do Their Roles Overlap?

The architect and interior designer may both contribute to floor plans, room proportions, lighting, materials and architectural details. This overlap can be valuable when responsibilities are clearly defined. For example, the architect may establish the overall layout and structural organization of an addition, while the interior designer refines the kitchen, furniture arrangement, storage and relationship between adjoining rooms. Both professionals might review: Room dimensions; Door and window placement; Ceiling heights and details; Stair design; Interior sightlines; Kitchen and bathroom locations; Lighting requirements; Material transitions; Built-in cabinetry; The relationship between old and new portions of the home.

The purpose of collaboration is not to duplicate the same work. It is to consider major decisions from multiple perspectives and coordinate them before construction begins.

Why Furniture Planning Matters to the Architecture

Furniture is sometimes treated as a final layer, but it can affect the architectural plan from the beginning.

The dimensions and placement of furniture influence room proportions, circulation paths, window locations and lighting and electrical layouts. A dining table, for example, helps determine the correct location for a ceiling fixture. A sectional influences the positioning of electrical outlets and circulation through a family room. A significant artwork may affect wall dimensions and lighting. When preliminary furniture plans are developed early, the architect and interior designer can ensure that the building supports the way the rooms will eventually be used.

Who Selects Interior Materials and Finishes?

Interior material selections are primarily led by the interior designer. These may include: Flooring; Tile and stone; Countertops; Cabinetry finishes; Paint colours; Wallcoverings; Plumbing fixtures; Decorative hardware; Decorative lighting; Interior doors and trim; Fireplace materials.

The architect may also specify architectural materials, exterior finishes and some interior elements. Major materials should be selected early enough to coordinate dimensions, transitions, lead times and pricing before they are needed on site.

Who Is Responsible for the Construction?

The builder or general contractor is normally responsible for executing and managing the construction. This commonly includes:

• Establishing the construction schedule

• Hiring and supervising trades

• Managing site operations

• Coordinating deliveries

• Maintaining site safety

• Preparing construction pricing

• Ordering construction materials

• Addressing construction methods

• Managing inspections

• Completing the work according to the construction contracts

The architect and interior designer may review portions of the work in relation to their drawings and design intent, but they do not replace the builder’s responsibility for construction management unless a separate agreement explicitly states otherwise.

Who Should Be Hired First?

There is no single sequence that applies to every project. If the renovation involves a major addition, structural changes or complex zoning requirements, an architect may be one of the first professionals consulted. However, the interior designer should still become involved before the architectural plans are finalized. In some cases, homeowners contact an interior designer first. The designer can help clarify the interior scope and introduce architects or builders whose experience may suit the project. The important point is not which professional receives the first telephone call. It is that the core team is assembled early enough to influence the plans and coordinate major decisions.

When Might You Need Only One?

A project may not require both an architect and an interior designer. A furnishing-only project that does not involve construction may be managed entirely by an interior designer. A limited architectural project with little interior scope might not require comprehensive interior design services.

However, a major renovation or addition usually contains both architectural and interior-design decisions. Homeowners should consider the complexity of the project rather than trying to assign all responsibilities to one professional solely for convenience. The appropriate team depends on the home, scope, location and applicable professional requirements.

Creating One Cohesive Home

The homeowner should not have to reconcile a collection of disconnected architectural and interior decisions. A coordinated project team considers how the building, interior details and furnishings support one another. This approach can produce a home that is structurally sound, functionally considered and visually cohesive. Four Blocks South collaborates with homeowners, architects, builders and specialized trades on major renovations, additions and custom homes in Toronto and select surrounding areas. Our full-service interior design work can begin during early architectural planning and continue through interior detailing, material selections, furnishings and final installation.