Ben SnapeAn architectural specification describes the materials, products, workmanship and performance required for a building project. It works alongside drawings and schedules to explain what the design team expects to be supplied and built.
To write a specification, define the scope of each work section, set out the requirements clearly, coordinate them with the drawings and agree who will review and issue the information. The guide below covers responsibilities, timing and common mistakes.
Who writes specifications?
Architects traditionally bear primary responsibility for preparing specifications, as they translate design intent into precise instructions. In many practices, senior architects, architectural technologists (often Chartered via CIAT), or in-house technical staff handle this.
Larger projects or busy practices often outsource to independent consultants (e.g., firms like SpecStudio) or employ full-time specifiers. These professionals focus on technical accuracy, coordination with drawings, and compliance with regulations.
Often, engineers (structural, MEP), quantity surveyors, or product manufacturers provide input, especially for performance specs or specialist sections. On design-and-build contracts, contractors may develop detailed specs later.
When are specifications written?
The RIBA Plan of Work 2020 (the standard framework for UK projects) structures this process across stages:
- Stage 2 (Concept Design): Initial outline specifications emerge to support feasibility, cost planning, and early decisions.
- Stage 3 (Spatial Coordination): Outline specifications develop further, often used for planning applications and refined cost information.
- Stage 4 (Technical Design): The main phase for detailed specifications. Architects or specifiers prepare full production information, including tender specs, coordinated with drawings, Building Regulations submissions, and specialist subcontractor inputs. This is typically before tendering.
- Later stages (5–7): Specs update as needed during construction (e.g., for variations), handover, or in-use reviews.
Develop specifications alongside the design and record who reviews each section. Late or uncoordinated changes can lead to errors or disputes. Use a specification authoring tool for writing and a project record for related files and collaboration.
Key spec writing mistakes
Specification writing errors often stem from time pressures, inadequate training, and reliance on outdated habits. These can lead to coordination issues, cost overruns, disputes, or non-compliance with regulations (e.g., Building Regulations or the Building Safety Act).
Here are the most frequently reported spec writing mistakes that architects make:
Copy-pasting from previous projects without adaptation
Architects often reuse specs from old jobs, and if they’re not attentive that leads to irrelevant clauses, incorrect materials, outdated standards, or references to unrelated project types. This “copy-paste culture” introduces errors that go unnoticed. Wrong project names, incorrect materials/products, retained irrelevant clauses from templates – all of that makes your work sool sloppy.
Use PlanMan’s document management module to store up-to-date neutral templates and text snippets for your specs.
Failing to coordinate specifications with drawings & models
Specs become outdated if they are not updated alongside design changes in drawings or BIM models. Conflicts arise and cause site arguments, RFIs, or buildability issues.
Over- or under-specifying
Over-specifying adds unnecessary detail, inflating costs; under-specifying leaves gaps, risking poor quality or contractor assumptions that lead to substandard work.
Blurring lines of design responsibility
Mixing performance requirements (contractor-responsible) with prescriptive details (architect-responsible) without clarity is always a problem, particularly on design-and-build or higher-risk buildings
Lack of proper change tracking and communication
Revisions are not clearly recorded or communicated, leading to outdated versions being used.
With the communication module added to PlanMan you can easily make sure the whole team is on the same page regarding the project.
Best practices and tips for specification writing
Specification writing is a critical part of the UK architectural process, and the following list compiles actionable best practices. Your goal as an architect is iterative, collaborative drafting that evolves from outline specs in Stage 2 to detailed tender documents in Stage 4.
Start early and iteratively
Begin outline specifications in RIBA Stage 2 (Concept Design) to inform feasibility and cost planning, avoid waiting until Stage 4 like some of the less organised practices do.
Review specifications whenever the design changes. Check references to drawings and BIM models, and record the revision issued for review or construction. Any automatic synchronisation depends on the authoring tools and connections you have configured.
Engage specialist consultants (e.g., envelope or cladding experts, akin to Architectural Consultants or ACs) from pre-construction material selection to balance aesthetics, budget, and performance. PlanMan lets you easily add and manage multiple co-consultants for each project.
Prioritize coordination and collaboration
Coordinate specs with drawings, schedules, and multidisciplinary inputs (e.g., structural engineers, M&E consultants, etc).
Hold regular cross-team reviews (e.g., bi-weekly in Stage 3) to flag discrepancies, such as mismatched materials in specs vs. Revit models.
Clearly delineate responsibilities: use performance specs for contractor-led elements and prescriptive for architect-controlled ones. See this post on building responsibility matrices.
Ask specialist consultants to check regulatory requirements and performance specifications. In the UK, this means tapping CIBSE or BSRIA members for regulatory checks – and make sure the specs include certified ratings for air/water infiltration and structural loads.
Use structured tools and templates wisely
Compare specification authoring tools such as NBS Chorus and SpecLink against your project requirements. Keep exported files with the project record, follow agreed file naming and revision rules and set appropriate team permissions.
Aim for “just enough” specificity: over-specifying inflates tenders, while under-specifying invites variations, but always demand complete documentation from specialists.
Focus on clarity, compliance, and risk mitigation
Write in plain, unambiguous language: use active voice, define acronyms on first use, and include decision logs for rationale.
Embed compliance checkpoints to reference current regulations and sustainability metrics.
Pre-approve alternatives with equal-or-better criteria to reduce repeated requests for information and assign clear accountability to consultants for handling queries, shop drawings, and variations.
Review, test, and learn
Conduct peer reviews and mock tender exercises in Stage 4 to simulate contractor interpretation. Once each project is complete, have a post-project analysis of all spec-related issues to refine future templates.
Consider partnering with reliable suppliers/consultants for end-to-end accountability evaluating fit early to avoid mismatches.
For further reading, NBS explains the role of construction specifications. Use review findings and site queries to improve your next specification.
How PlanMan helps with specification writing
PlanMan (planman.app) is a cloud-based project management tool designed for UK architects and city planners. These are the key benefits for specification writing that PlanMan offers:
Centralized storage
Upload specification files, such as exported PDFs, against the relevant project. Keep them alongside related documents and use a clear naming convention to identify their revision and purpose.
Easy access & search
Global search quickly locates spec documents; access from any device (no VPN needed), ideal for on-site updates or Stage 4 technical design coordination.
Controlled sharing
Granular permissions for team members; client portal for secure 24/7 viewing of approved specs (e.g., for reviews), while keeping drafts private.
Security & reliability
Review the practice’s access settings and retention procedures when storing specification records. See PlanMan’s privacy policy for information about how data is handled.
Collaboration support
With PlanMan you can store specs with project notes, emails, and co-consultant inputs; the tool facilitates multidisciplinary reviews to avoid coordination conflicts.
Try PlanMan free for 30 days to see how specification files fit alongside your project records.