Building Drawings Explained: How a Drawing Set Is Organised

A building is designed and built from a set of drawings, not a single sheet. Those building drawings are produced by several disciplines, evolve through a sequence of project stages, and serve different readers: clients, authorities, quantity surveyors, contractors, specialist fabricators and, eventually, the people who maintain the building. Understanding how the set is organised makes any individual drawing far easier to read.

This article explains the disciplines that contribute to a drawing set, how drawings develop from concept to as-built, how they are numbered, revised and issued, and how they relate to regulatory approval in Singapore. It complements our guide to architectural drawing types and conventions, which covers the visual language of individual sheets.

The disciplines in a set of building drawings

Architectural drawings

The architect’s drawings describe the building’s layout, form, appearance and finishes: site plan, floor plans, roof plan, sections, elevations, reflected ceiling plans, details and schedules of doors, windows and finishes. They are usually the reference that other disciplines coordinate to. Homeowners meeting them for the first time may find our guide on how to read house plans helpful.

Structural drawings

The structural engineer’s drawings show the load-bearing frame: foundations and piles, pile caps, ground beams, columns, walls, beams and slabs, with member sizes, concrete grades, reinforcement and steel connections. They share the architectural gridlines and levels but describe what holds the building up. Our article on structural drawings explains how to read them.

Mechanical and electrical (M&E) drawings

Building services engineers produce drawings for air-conditioning and mechanical ventilation, plumbing and sanitary systems, electrical power and lighting, fire protection, lifts and other systems. On larger projects, combined services drawings coordinate these with each other and with the structure.

Civil and external works drawings

Civil engineers produce drawings for earthworks, roads, driveways, drainage, sewers and external utilities, often prepared in tools such as Civil 3D.

Specialist drawings

Façade consultants, landscape architects, interior designers, lighting designers and others add their own drawings, each referenced to the same grids and levels.

How building drawings develop through a project

Drawings are not produced once. They are developed and reissued as the design matures, and each stage serves a different purpose.

Concept and schematic drawings establish the design idea, massing and layout. They are diagrammatic and change frequently.
Design development drawings fix the main dimensions, structural system, services strategy and materials, and coordinate the disciplines.
Submission drawings are prepared for regulatory approval, showing what the authorities need to assess.
Tender drawings describe the works sufficiently for contractors to price them, together with specifications and bills of quantities.
Construction drawings are issued for building, with full dimensions, details and coordination. They are often marked with a status such as “for construction”.
Shop drawings are produced by contractors and fabricators, showing exactly how they will make and install components such as steelwork, precast elements, façades or joinery. The design team reviews them against the design intent.
As-built drawings record the building as actually constructed, including any changes made on site. They are essential for future maintenance, alteration and inspection.

Numbering, revisions and issue status

A drawing set is a controlled document. Each sheet has a unique number, usually encoding the project, discipline, drawing type and sequence, so that “S-201” or a similar code identifies a structural drawing unambiguously. A drawing register lists every sheet with its current revision and status.

Every change is recorded as a revision, with a letter or number, a date and a short description, and the changed area is often marked with a revision cloud. A transmittal records which drawings were issued to whom and when. These administrative details are not bureaucracy for its own sake: building from a superseded revision is one of the most common and expensive mistakes on site, and the revision record is how disputes about what was instructed are resolved.

Building drawings and approvals in Singapore

In Singapore, building works are subject to approval by several agencies, and the drawings are prepared and submitted by Qualified Persons, typically a registered architect or a Professional Engineer. Planning matters such as use, intensity and envelope are dealt with by URA; building plans covering matters such as safety, accessibility and building control requirements are submitted to BCA; and structural plans, with calculations, are submitted to BCA by the Professional Engineer responsible for the structural design. Other agencies, including SCDF for fire safety, PUB for drainage and sanitary works, LTA and NEA, have their own requirements. Our articles on BCA building plan submission and structural plan submission explain these processes further.

Submission is increasingly model-based. Under CORENET X, the integrated regulatory platform, new projects of 5,000 m² gross floor area and above have been required since 1 October 2026 to submit through its gateway processes using IFC+SG models, with smaller projects able to continue on existing routes for now. Whatever the format, the content is the same: a coordinated, complete description of the proposed building.

Coordination between drawing sets

The most important quality of a drawing set is that the disciplines agree. A beam on the structural drawing must fit within the ceiling zone on the architectural section; a duct on the M&E drawing must pass beneath it or through a properly designed opening; a floor trap on the plan must have a fall and a drain beneath the slab.

BIM tools and federated model reviews have made coordination far more reliable, but it still depends on people checking and agreeing. Where drawings conflict, the general rule in most contracts is that the contractor must raise a query rather than guess, and the design team resolves it. Structural discrepancies, in particular, should never be settled on site by assumption.

Building drawings for existing buildings

For renovation and alteration work, the starting point is usually the existing drawings, if they can be found. In Singapore, approved plans for many buildings can be requested from the authorities, and HDB and condominium management may hold relevant records. Even so, existing drawings may not reflect later changes, so a measured survey and, where structure is affected, an engineering inspection are prudent. That is especially true before A&A works, where the structural behaviour of the existing building must be understood before it is altered.

Frequently asked questions

What are building drawings?

Building drawings are the coordinated set of architectural, structural, mechanical and electrical, civil and specialist drawings that describe a building for approval, pricing, construction and maintenance. Together with specifications, they define what is to be built.

What is the difference between construction drawings and shop drawings?

Construction drawings are produced by the design team to describe the works. Shop drawings are produced by contractors and fabricators to show how they will make and install particular components, and are reviewed by the design team against the design intent.

What are as-built drawings?

As-built drawings record the building as actually constructed, including changes made during construction. They are important for future maintenance, alterations, inspections and any later structural assessment.

Who prepares building drawings for approval in Singapore?

Drawings for regulatory approval are prepared and submitted by Qualified Persons, typically registered architects for building plans and Professional Engineers for structural plans. Other consultants contribute drawings for specific systems such as fire safety, drainage and building services.

What should I do if two drawings disagree?

Raise the discrepancy with the design team before work proceeds. Contractors should not resolve conflicts by assumption, particularly where structure is involved, because the correct answer may depend on design information that is not shown on either drawing.

Working from old drawings or planning alterations to an existing structure? Talk to our consultancy or get in touch.