Interior design is more than selecting materials and arranging furniture. It is a structured process that transforms an interior space into one that is functional, efficient, and aesthetically aligned with the needs of its users.

According to the Environmental Protection Agency, people spend 90% of their time indoors. This makes the interior environment critical to comfort, productivity, and well-being. Whether a project involves a renovation, a tenant improvement, or new construction, most interior design projects follow a consistent series of phases.

This guide outlines the five key phases of the interior design process, with a focus on commercial tenant improvement projects. These phases are:

1. Programming

2. Schematic Design

3. Design Development

4. Construction Documents

5. Construction Administration

What Is Interior Design and Why Is It Important?

Interior design is the creation of environments that respond to human needs. Interior designers consider how spaces function and feel while coordinating finishes, furniture, lighting, and systems. The goal is to make a space both practical and enjoyable to use.

Interior design projects support more than aesthetic goals. They improve wayfinding, maximize usable space, increase productivity, and support brand identity. Interior designers also address technical requirements such as fire ratings, accessibility, and mechanical coordination.

Who Is Involved in the Interior Design Process?

Interior design projects often involve multiple contributors:

• Interior designers

• Architects (depending on project scope)

• Clients (building owners, tenants, or developers)

• Consultants (structural, mechanical, electrical, plumbing, lighting)

• FF&E vendors (furniture, fixtures, and equipment suppliers and installers)

Depending on the size and complexity of the project, additional stakeholders may include:

• A client’s facilities team (security, IT, food and beverage, etc.)

• Landlords, who may require adherence to building standards

• Environmental graphic designers (EGD), who design wayfinding and branding systems

What Types of Projects Involve Interior Design?

Any project with a usable interior space will typically include interior design. This includes homes, offices, museums, medical clinics, restaurants, and institutional buildings. The scope varies by project type:

• Tenant improvement (TI): Commercial spaces tailored to tenant needs

• Remodeling: Interior upgrades to an existing space

• Adaptive reuse: Transforming an existing building for a new function or occupancy type

• Ground-up construction: New buildings that include interior design as part of the core team

Phase 1: Programming

The goal of the Programming phase is to define the project’s scope and constraints.

Different organizations will have different spatial and operational needs. For example, a law firm and a creative agency may both need conference rooms, but the design requirements for each will vary. Programming helps clarify those needs.

Interior designers lead work sessions with the client and stakeholders to understand the business structure, space functions, and goals. Deliverables for this phase often include:

• Site visits to gather field data and create a survey report

• Creation or verification of a Revit model as the basis for design

• Programming spreadsheet defining room types and square footages

• Preliminary bubble diagrams and space planning sketches

• Project scope and schedule documentation

• Inspiration and precedent imagery

You can use Layer to organize this phase with a programming spreadsheet that tracks requirements by room and links to precedent images or Room Data Sheets.

Phase 2: Schematic Design

The goal of Schematic Design is to explore design solutions through test fits and conceptual studies.

A test fit is a scaled floor plan that confirms the general location and size of spaces. It validates whether a proposed layout meets program requirements. The test fit is often attached to the lease agreement between tenant and landlord.

Typical tasks and deliverables in Schematic Design include:

• Concept boards that define the “look and feel” of the space

• Multiple test fit options based on the approved program

• Schematic 3D views or renderings

• An initial cost estimate

• A presentation to the client and landlord for feedback

Layer supports schematic design by building upon the programming phase. Users can expand their room spreadsheet with mood board images and generate templated Room Data Sheets for review and approval.

Phase 3: Design Development

The main goal of Design Development is to narrow in on a solution and dive into the design details.

In Design Development, the client and interior designer agree upon a single direction. The approved test fit and mood board from schematic design serve as the starting point.

Some aspects of the layout and design may shift as interior designers layer detail into the drawings. Keeping the client in the loop through frequent design review meetings enables the design team to solidify the project elements before the Construction Documentation phase.

Deliverables typically include:

• Detailed floor plans, interior elevations, and ceiling plans

• Selection of materials, finishes, and lighting

• FF&E specifications and schedules

• Coordination with consultants (MEP, structure, lighting)

• Updated renderings and branding integration

• Refined cost estimate and client sign-off

Layer’s FF&E Template helps teams organize and track furniture and material selections. You can also use Meeting Minutes templates to document approvals and design changes throughout this phase.

Phase 4: Construction Documents

The goal of the Construction Documents phase is to assemble final documentation set for bidding and the construction phase.

The final documentation set has several drawings, schedules, and visuals used for pricing and the realization of the space. Interior designers coordinate the set with consultants and review drawings for quality.

The length of the documentation set will vary depending on project type and complexity. It is common to conduct page-turn meetings with the client to review key drawings from the set for their approval.

If the client is not attuned to reviewing construction drawings, simplify the drawings and annotate areas that need more attention. This will ensure nothing falls through the cracks.

This phase may include:

• Page-turn meetings with the client to review and approve final drawings

• A coordinated set of documents issued for bidding, permitting, and construction

• Coordination with landlords for final approval

• Drawing markups and redlines based on quality control and feedback

Layer supports this phase by allowing teams to mark up PDFs and respond to RFI templates within a central dashboard.

Phase 5: Construction Administration

The goal of Construction Administration is to support execution and project closeout.

During this phase, interior designers are actively on-site or coordinating with contractors. They answer RFIs, review submittals, walk the site for punch lists, and help the client navigate final steps like move-in or post-occupancy evaluation.

Deliverables include:

• Responses to RFIs

• Coordination with vendors for installation

• Punch list documentation

• Submittal reviews

• Site visit photos and update emails

• As-built drawings and model updates (if required)

• Project handoff documentation

• Post-occupancy evaluation (POE)

Layer’s Punch List Template helps designers create and track open items with photo documentation, notes, and resolution statuses.

What Are the Final Deliverables in Interior Design?

Interior designers deliver more than just drawings. Depending on the project phase and client needs, deliverables may include:

• Programming spreadsheets and summary reports

• Concept boards and inspiration imagery

• Room Data Sheets and FF&E schedules

• Interior elevations and detail drawings

• 3D renderings and material palettes

• Construction document sets

• Punch lists and site visit reports

• As-built documentation and post-occupancy evaluations

Deliverables are used by clients to make decisions about scope, budget, phasing, and compliance. Structuring these documents early in the process helps reduce rework and supports better coordination across teams.

What's Next?

This guide outlines the full interior design process from start to finish. While every project is unique, most follow the same core phases: programming, schematic design, design development, construction documentation, and construction administration.

To explore related topics and deepen your understanding of the design process, continue reading:

• Tips for Using Layer in the Field

• The FF&E Process Explained

• An Introduction to Adaptive Reuse Architecture

For teams looking to streamline their interior design workflow and keep project data organized across all five phases, try out a Layer demo or explore our template library.