Interior Design for Architects: Scope, Process, and Performance Criteria

What Architects Commonly Own vs. Coordinate

Interior design in architectural practice typically sits on a spectrum: some decisions are fully authored by the architect, while others are coordinated with interior designers, consultants, vendors, and the contractor. Clarifying ownership early prevents gaps (no one specifies it) and overlaps (two teams specify it differently).

Decisions architects commonly own

• Finish intent and selection framework: overall palette direction, performance requirements, and where each finish is used (even when final selections are vendor-assisted).
• Lighting intent: qualitative goals (brightness, glare control, mood, hierarchy) and how lighting supports wayfinding and tasks; coordination of fixture types and controls with MEP/lighting designer.
• Junction detailing: how materials meet (base, reveals, trims, corner guards, transitions, expansion joints), including constructability and tolerance strategy.
• Documentation and coordination: finish schedules, reflected ceiling plans (RCP), interior elevations, millwork details, and integration with life safety, accessibility, and MEP constraints.

Decisions architects commonly coordinate (but must still verify)

• Specialty lighting calculations (photometrics, emergency lighting) and control sequences (often by lighting designer/MEP).
• Acoustic assemblies and ratings (often by acoustician), while ensuring details match the rated assembly.
• Fire performance (firestopping, flame spread, smoke development, rated partitions) with code consultant and contractor.
• Furniture, equipment, and signage (FF&E/graphics), ensuring clearances, power/data, and mounting are coordinated.

Project Inputs: What You Need Before You Decide

Interior decisions are only as good as the inputs. Treat inputs as constraints and opportunities, then translate them into measurable criteria and drawings.

1) Client brief (functional + experiential)

• Program and adjacencies: what happens in each room, occupancy, peak loads, and privacy needs.
• Brand/identity cues: desired tone (calm, energetic, premium, playful) and any non-negotiables (signature color, material, or feature wall).
• Operations: cleaning protocols, maintenance staff capability, replacement cycles, and expected abuse (public-facing vs. staff-only).
• Budget and procurement: allowance-based vs. specified products; lead times; alternates strategy.

2) Building code constraints (interior-facing)

• Accessibility: clearances, reach ranges, protruding objects, slip resistance expectations, hardware, and signage requirements.
• Fire/life safety: interior finish classifications, rated corridors/shafts, smoke partitions, egress lighting, and door hardware requirements.
• Health requirements: where low-VOC or specific hygiene requirements apply (e.g., healthcare, food service).

3) Base building conditions (what you inherit)

• Existing shell and MEP: ceiling plenum depth, sprinkler layout constraints, diffuser locations, structural drops, and existing lighting circuits.
• Substrates: slab flatness, wall conditions, moisture levels, and existing coatings that affect adhesion and finish performance.
• Constraints on penetrations: post-tension slabs, fire-rated assemblies, acoustic separations, and landlord rules (tenant improvements).

Practical step: run an “interior feasibility walk” (or virtual review) and capture a short punch list of constraints that will directly shape finishes and details: ceiling height pinch points, wet areas, high-traffic corners, daylight/glare zones, and any areas requiring rated or acoustic assemblies.

Set Performance Criteria Before Selecting Materials

Performance criteria turn subjective preferences into testable requirements. Establish them early, then use them to evaluate options and document expectations.

Durability

• Traffic-based zoning: define zones (low/medium/high abuse) and assign minimum performance per zone.
• Impact and scratch resistance: corners, cart paths, chair rails, and door swing zones need higher resilience.
• Moisture resistance: wet rooms, entry vestibules, and below-grade areas require appropriate assemblies, not just “waterproof-looking” finishes.

Maintainability

• Repair strategy: can a damaged piece be patched invisibly, or must a whole panel be replaced?
• Access: ensure access panels align with MEP valves, dampers, and junction boxes; avoid burying equipment behind fixed millwork.
• Spare parts: define attic stock quantities for flooring, wall coverings, and ceiling tiles.

Comfort (visual, thermal, tactile)

• Glare control: matte vs. glossy finishes, shielding angles, and placement of luminaires relative to sightlines.
• Thermal perception: material touch temperature (metal vs. wood), draft sensitivity near diffusers, and radiant asymmetry near glazing.
• Wayfinding comfort: consistent lighting levels and clear transitions between zones.

Acoustics

• Absorption vs. isolation: absorption (reducing reverberation) is different from isolation (blocking sound transfer). Specify which problem you’re solving in each space.
• Target metrics: set targets such as maximum reverberation time (RT) for key rooms, and minimum partition performance where privacy is required.
• Detail sensitivity: small gaps at head-of-wall, unsealed penetrations, and back-to-back outlets can undermine acoustic intent.

Fire performance

• Finish classification: define required flame spread/smoke development class for wall/ceiling finishes where applicable.
• Rated assembly integrity: ensure millwork, glazing, and penetrations do not compromise rated partitions; coordinate firestopping requirements.

Indoor air quality (VOCs and emissions)

• Low-emitting materials: set requirements for adhesives, sealants, paints, coatings, and composite wood products.
• Installation sequencing: plan for ventilation/flush-out if required; avoid trapping odors behind impermeable finishes.

Cleanability and hygiene

• Cleaning agents: confirm finishes tolerate the client’s cleaning chemicals (e.g., disinfectants can haze some plastics and coatings).
• Detailing for hygiene: minimize dirt-catching ledges; use coved bases in wet/clinical areas; seal joints appropriately.

Performance criteria matrix (template)

Workflow: From Concept Palette to Coordinated Documents

The goal is to move from intent to buildable, coordinated information without losing performance requirements. The workflow below is practical for small and large teams; scale the depth, not the sequence.

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Step 1: Establish interior scope boundaries

• Define what is included: partitions, ceilings, flooring, wall finishes, millwork, lighting fixtures, controls intent, hardware, accessories.
• Define what is excluded or delegated: loose furniture, signage, specialty equipment, landlord work, IT/security devices.
• Confirm responsibility matrix (who specifies, who reviews, who approves).

Step 2: Build a concept palette tied to performance

Create a limited set of “material families” (e.g., resilient flooring family, feature wall family, ceiling family) and attach performance criteria to each family. This keeps the concept phase from becoming a shopping exercise.

• Deliverable: concept boards or a digital palette sheet with: material intent, finish direction, and performance notes.
• Practical check: for each family, write one sentence: “This material is here because…” (durability, acoustics, brand, cost, maintenance).

Step 3: Test junctions early (mini-details)

Before final selections, sketch the critical junctions that will make or break the interior: floor-to-wall base, wall-to-ceiling, outside corners, wet area transitions, and millwork interfaces.

• Identify tolerance strategy: reveals, trims, scribe conditions, and where you allow movement.
• Coordinate with structure/MEP: avoid conflicts at soffits, bulkheads, access panels, and sprinkler/lighting alignments.

Step 4: Coordinate lighting intent with ceiling and layout

• Set lighting layers per space: ambient, task, accent, and emergency.
• Align fixture types with ceiling system: recessed vs. surface, linear vs. point sources, and maintenance access.
• Confirm glare control: fixture placement relative to primary sightlines and reflective surfaces.

Step 5: Develop the finish plan and schedule in parallel

Do not wait for “final selections” to start documentation. Use placeholders with performance requirements, then lock products as approvals come in.

• Finish plan shows where each finish code applies.
• Finish schedule defines what each code means (material, color, manufacturer, performance notes).

Step 6: Produce interior elevations and key details

• Elevations communicate intent and coordination: heights, alignments, reveals, backing, and accessory locations.
• Details translate intent into buildable assemblies: edges, transitions, fasteners, substrates, and sealants.

Step 7: Integrate specifications and procurement strategy

• Write performance-based specs where substitutions are likely; write proprietary specs where exact match is critical.
• Define submittal requirements: samples, mockups, test data, and installation instructions.
• Plan alternates: pre-approved substitutions to protect schedule and budget.

Step 8: Coordination review and clash prevention

• Run coordinated checks: RCP vs. sprinklers/diffusers, millwork vs. power/data, door swings vs. wall protection, accessibility clearances.
• Verify rated and acoustic assemblies: confirm details match the tested assembly requirements.

Step 9: Mockups and field verification

• Require a representative mockup for high-visibility or high-risk items (feature wall, flooring transitions, custom millwork, lighting effects).
• Use mockups to lock: sheen levels, grout color, reveal widths, edge profiles, and acceptable tolerances.

Checklist: Required Interior Deliverables

Use this checklist to confirm your set is complete and coordinated. Adjust to project size and delivery method.

Drawings

• Finish plans: by level/area, with finish codes and extents.
• Reflected ceiling plans (RCP): ceiling types, heights, soffits, lighting layout, diffusers/sprinklers coordination notes, access panels.
• Interior elevations: key rooms, corridors, reception, restrooms, kitchens/pantries; include dimensions, heights, and alignments.
• Millwork elevations and sections: casework, reception desks, wall panels, banquettes; include hardware and access requirements.
• Details: base conditions, transitions, corner guards, reveals, wet area waterproofing interfaces, glazing-to-wall, ceiling-to-wall, expansion joints.
• Door and hardware coordination: door schedule references, frame types, vision panels, kick plates, closers, and access control interfaces.

Schedules

• Finish schedule: floors, bases, walls, ceilings; include performance notes and installation requirements.
• Ceiling schedule: ceiling types, heights, acoustical properties if relevant.
• Fixture schedule (interior-related): lighting fixture types (in coordination with lighting/MEP), plumbing fixtures, accessories, and specialty items as applicable.
• Millwork schedule: materials, edge profiles, hardware sets, and finish system.

Specifications and supporting documents

• Fixture specifications: cut sheets, lamping/driver requirements, controls intent notes, mounting details.
• Material specifications: performance requirements (wear layer, slip resistance, cleanability, VOC/emissions), substrates, adhesives, sealants.
• Mockup requirements: scope, acceptance criteria, and what becomes the “quality benchmark.”
• Submittal log requirements: what must be submitted and approved before ordering.

Decision Log: Format to Track Approvals and Changes

A decision log is a lightweight tool that prevents rework and disputes. It records what was decided, by whom, when, and what it affects (drawings, specs, cost, schedule). Keep it live from concept through construction administration.

Decision log fields (recommended)

• ID: unique identifier (e.g., INT-045).
• Date raised and required-by date.
• Decision topic: e.g., “Lobby floor finish selection.”
• Location: level/room numbers.
• Options considered: A/B/C with brief pros/cons tied to performance criteria.
• Performance criteria impacted: durability, acoustics, fire, VOC, cleanability, maintainability.
• Cost impact: allowance, add/deduct, TBD.
• Schedule/lead time impact: long-lead flag and procurement deadline.
• Approver(s): client, architect, landlord, consultant.
• Status: proposed / under review / approved / superseded.
• Documentation impact: list sheet/spec sections to update.
• Change reference: ASI/RFI/CCD/CO number if applicable.

Decision log table (copy/paste template)

Practical step-by-step: how to use the log weekly

• Step 1: At the end of each coordination meeting, capture new decisions and assign an owner and required-by date.
• Step 2: Before issuing a drawing set, filter the log for “approved” items and verify they are reflected consistently in plans, elevations, schedules, and specs.
• Step 3: When a change occurs, mark the prior decision as “superseded,” add a new entry, and reference the formal change instrument (ASI/RFI/CCD/CO) to keep traceability.
• Step 4: Use the log to drive procurement: highlight long-lead items and confirm submittal dates align with construction sequencing.