In this guide — 8 sections
Approval drawings are the minimum set submitted to CMDA, GCC or DTCP to obtain Planning Permission. They show footprint, setbacks, height, FSI compliance and general layout — enough to satisfy the authority, not enough to build from. Construction drawings, or GFC drawings — Good for Construction — are the full, dimensioned, coordinated set issued to the contractor. They include structural reinforcement details, MEP layouts, detailed dimensions, material specifications and junction details that approval drawings never contain.
When a homeowner in Chennai engages an architect, one of the most common misunderstandings is about what “drawings” the architect will produce. Many assume the drawings used to get the CMDA or GCC approval are the same drawings the contractor builds from. They are not — and this confusion causes real problems when construction begins.
Understanding the difference between approval drawings and construction drawings is not a technical detail for architects to care about and homeowners to ignore. It is a practical question with direct consequences for your budget, your construction quality, and your ability to hold your contractor accountable on site. Our architects in Chennai address this distinction with every client before a single sheet is drawn.
Approval drawings are the set of architectural drawings submitted to the relevant planning authority — CMDA, GCC or DTCP depending on the plot’s jurisdiction — to obtain Planning Permission. In Tamil Nadu this submission is processed through TNOBPAS, the Tamil Nadu Online Building Plan Approval System. Approval drawings demonstrate regulatory compliance: setbacks, FSI, plot coverage, height, parking provision and general arrangement. They are reviewed by technical staff at the authority, not by a contractor. The detail level is calibrated to what the authority needs, not to what a builder needs.
GFC drawings are the fully detailed, approved and formally issued set from which the contractor physically builds the structure. Every GFC sheet carries a “Good for Construction” stamp or revision code with the issue date and architect’s authorisation. Earlier revisions labelled “Preliminary”, “For Approval” or “For Review” are not GFC drawings and must not be used on site. The set includes architectural, structural and MEP drawings at a level of detail that enables every trade to work from the same coordinated information.
What Approval Drawings contain
The TNOBPAS submission for a residential building in Chennai typically requires the following drawing sheets:
- Site plan — key plan and location plan showing the plot in its neighbourhood context
- Floor plans for every level — room names, approximate dimensions, and setbacks from the plot boundary
- All four elevation drawings — north, south, east and west façades
- At least two section drawings — longitudinal and cross-section
- Roof plan showing drainage and parapet heights
- Area statement confirming total built-up area and FSI compliance
- Structural stability certificate signed by a COA-registered structural engineer
Detailed wall dimensions, column and beam sizes, reinforcement specifications, foundation details, electrical layouts, plumbing drawings, waterproofing specifications, door and window schedules, or material callouts. These are architectural and engineering decisions — but they are not required by the planning authority to grant permission, so they are typically absent from approval submissions.
Approval drawings confirm that the proposed building complies with TNCDBR development control regulations — setbacks, height, FSI, parking and general layout. They do not and cannot confirm how the building will be built. An architect who submits drawings to CMDA or TNOBPAS has confirmed legal compliance. They have not produced a construction instruction set. These are two distinct professional products.
What Construction (GFC) Drawings contain
A complete GFC drawing set for a Chennai residential house typically includes all of the following, across three disciplines:
Architectural GFC drawings
5 sheet types- Dimensioned floor plans at 1:50 scaleEvery room dimension, wall thickness, column position, door and window opening width, and grid line reference.
- Detailed elevation drawingsSill and lintel levels, window and door heights, parapet dimensions, façade material zones, and reference to detail drawings.
- Section drawings with levelsFloor-to-floor heights, slab thickness, beam depths, roof profile, staircase tread and riser dimensions, and headroom clearances.
- Door and window scheduleEvery opening listed with type, size, material, hardware, and reference to the elevation where each appears.
- Detail sheets at 1:10 to 1:2 scaleParapet coping, sill junction, door frame section, staircase nosing, and other construction junction details.
Structural GFC drawings
4 sheet types- Foundation planColumn footing positions, depths and reinforcement details.
- Column scheduleColumn cross-sections, longitudinal bars and links for each storey.
- Beam and slab layout plansSpan, depth, reinforcement, and reference to standard details for each floor.
- Bar bending schedule (BBS)Detailed tabulation of every reinforcement bar — shape, size, length and quantity — enabling the steel fabricator to cut and bend bars precisely before they reach site.
MEP drawings
Mechanical, electrical, plumbing- Electrical layoutPoint positions for lights, fans, sockets, AC and DB, conduit routes, and the circuit schedule.
- Plumbing and drainage layoutFixture positions, stack locations, drain slopes, sump connection and rainwater harvesting provision.
All sheets in the GFC set are formally issued — stamped, signed by the responsible professional, dated, and listed in a drawing register. Any drawing not formally issued as GFC is not a construction instruction.
A Coordinated GFC Set, Issued and Stamped Before Work Starts
Dimensioned plans at 1:50, detail sheets, foundation and column schedules with BBS, and MEP layouts agreed before the first slab is cast.
Approval vs Construction Drawings — the comparison
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| Aspect | Approval drawings | GFC / construction drawings |
|---|---|---|
| Purpose | Satisfy the planning authority — demonstrate regulatory compliance | Enable construction — give the contractor and trades all information to build |
| Who uses them | Planning authority (CMDA / GCC / DTCP), architect for submission | Contractor, site supervisor, structural engineer, MEP subcontractors |
| Typical scale | 1:100 floor plans, 1:200 site plan | 1:50 floor plans, 1:10–1:2 detail drawings |
| Dimensions shown | Room names, approximate areas, setbacks from boundary | Full dimensions — wall-to-wall, opening widths, floor heights, slab thicknesses |
| Structural details | Structural stability certificate only — no reinforcement details | Full reinforcement drawings, BBS, column and beam schedule, foundation details |
| MEP information | Not included | Electrical layout, plumbing layout, drainage routing |
| Material specifications | Generally not included, except the structural certificate | Material callouts, product specifications, finish schedules |
| Detail drawings | Not required | Junction details, door sections, staircase nosing, parapet coping |
| Submission platform | TNOBPAS — Tamil Nadu Online Building Plan Approval System | Issued by the architect to the contractor — not submitted to any authority |
| Legal status | When sanctioned, grants Planning Permission | No regulatory submission — a working document between design team and contractor |
| Can be used to build? | NoInformation is insufficient for construction | YesThis is the purpose of the document |
Exact drawing requirements vary by project type, number of floors, jurisdiction, approval authority and consultant scope. Always confirm the drawing deliverables required for your specific project with your architect before finalising the fee.
Why Approval Drawings cannot be used for construction
This is the question that matters most to a Chennai homeowner about to start building. The practical answer is that approval drawings lack the information a contractor needs to build correctly. Here is what happens when a site team tries to build from them alone:
What goes wrong when GFC drawings are missing
Six failure modes, structure to budgetColumn positions are not dimensioned. The structural engineer’s column grid is absent from approval drawings. Without it the contractor positions columns by estimate — and any error must be corrected at great cost once the concrete is poured.
Reinforcement is not specified. The approval set includes a structural stability certificate but not the reinforcement schedule. Bar sizes, spacing and splicing positions are not known on site, so the contractor uses their own judgement — which may be conservative or unsafe.
Slab thickness is not confirmed. Approval drawings show a section but typically do not specify exact slab thickness, concrete grade or reinforcement cover. Site decisions are then made without engineering backing.
MEP conflicts are not resolved. Conduit runs and plumbing stacks are positioned on site without coordination against the structural grid. Conduits run through beams; stacks conflict with columns. These conflicts surface only when it is expensive to fix them.
Door and window openings are cut incorrectly. Without a schedule showing exact frame size and rough opening, masons cut openings to their best estimate — and frames ordered from a manufacturer may not fit.
Variation orders multiply. Every missing specification becomes a contractor decision, and a potential variation. The absence of GFC drawings is the primary driver of budget overruns in Chennai residential construction.
Planning Permission is a legal achievement. The GFC set is what converts a legal permission into a buildable instruction.
— Two documents, two different jobs
What to Confirm in your architect’s fee scope
The single most important question to ask before signing an architectural fee proposal is: what drawing deliverables does this fee include, and at which stages?
In Chennai’s architectural market, fee proposals vary widely. Some architects quote for CMDA approval drawings only — the minimum needed to get Planning Permission. Others include a full GFC set. Many are ambiguous, using terms like “construction drawings” that could mean either. Before signing any agreement, confirm the following in writing:
Confirm in the architect’s fee scope
8 questions- Is CMDA / TNOBPAS approval submission included — all required drawing sheets for Planning Permission?
- Is a full set of GFC architectural drawings at 1:50 scale included — floor plans, elevations, sections?
- Are architectural detail drawings at 1:10 to 1:2 scale included — junction details, door sections, staircase?
- Are structural drawings included, or is the structural engineer’s fee separate?
- Is the bar bending schedule (BBS) included in the structural scope?
- Are MEP drawings — electrical layout, plumbing layout — included, or are these by specialist consultants under a separate fee?
- Is a drawing register — a list of all drawings with revision status — provided?
- What revision rounds are included — how many changes to GFC drawings sit within the fee scope?
A fee proposal that includes “architectural drawings and CMDA submission” typically means approval drawings only. It does not automatically include GFC drawings, structural drawings, MEP layouts or construction detail sheets. A fee that includes “construction drawings” may mean GFC architectural drawings only — without structural or MEP, which are produced by separate consultants under separate fees. Neither interpretation is wrong; they reflect different scopes. The problem is when the homeowner assumes one and the architect intends the other. Clarify in writing before signing.
Know Exactly Which Drawing Stages Your Fee Covers
Approval submission, GFC architectural, structural with BBS, MEP layouts and revision rounds — set out sheet by sheet before the appointment is signed.
Confirming Your Drawing Set before construction begins
Follow this process before allowing construction to begin:
- Confirm Planning Permission is in handThe TNOBPAS-issued Planning Permission — the stamped, signed sanction order — must be received from CMDA, GCC or the local body before any construction begins. Obtaining this was the purpose of the approval drawings.
- Request the drawing registerAsk your architect for the current register: the list of all drawings prepared for the project, their revision number and their current status. Every sheet should be identifiable.
- Confirm GFC issue status on each sheetCheck that every sheet the contractor needs has been formally issued as GFC. Look for the revision code — often “Rev A — GFC” or similar — the issue date, and the architect’s or engineer’s signature or stamp on the title block.
- Confirm structural drawings are in handThe foundation plan, column schedule, beam and slab layout, and BBS should all be GFC-stamped and in the contractor’s possession before structural work begins.
- Confirm MEP layouts before the first slabElectrical conduit routes and plumbing stack positions must be agreed and drawn before the structural slab is cast. Once concrete is poured, changes require demolition.
- Confirm that no preliminary drawings are on siteCheck the site office for drawing copies. Any sheet marked “Preliminary”, “For Approval” or “For Review” should be removed and replaced with the current GFC issue. Working from superseded drawings is a common cause of costly errors.
Key Takeaways — what every Chennai homeowner should confirm
Five things to settle before the first pour
Scope, detail and issue statusApproval drawings and construction drawings serve different purposes. Approval drawings get you Planning Permission; GFC drawings tell the contractor how to build.
A GFC set is significantly more detailed than an approval set — full dimensions, structural reinforcement details, MEP layouts and construction junction details that approval drawings never contain.
Building from approval drawings without a GFC set is the most reliable way to generate variation orders, structural errors and MEP conflicts that cost significantly more to fix than the GFC drawings would have cost to prepare.
Before signing an architect’s fee proposal, confirm in writing which drawing stages are included — approval only, GFC architectural, structural, or MEP.
Before construction begins, confirm that every drawing sheet on site is GFC-stamped and current. Preliminary or superseded drawings have no place on an active construction site.
Frequently Asked Questions
What are GFC drawings?
GFC stands for Good for Construction. GFC drawings are the formally issued, fully detailed architectural, structural and MEP drawings from which the contractor builds the actual structure. Each sheet carries a stamp or revision code confirming it has been reviewed, approved and formally issued for construction use. They are distinct from preliminary, approval or concept drawings — only GFC-issued sheets should be used on site.
Can I build from approval drawings?
No. Approval drawings contain the minimum information needed to obtain Planning Permission from CMDA, GCC or DTCP, but they lack the detail required for construction. They do not include structural reinforcement details, exact room dimensions, MEP layouts, construction junction details, or the bar bending schedule needed by the steel fabricator. Using them without a GFC set results in site teams making decisions that should have been made by the structural engineer and architect — leading to errors, variation orders and potential structural risk.
Are construction drawings included in the architect’s fee?
This depends entirely on the scope agreed with your specific architect. Some fee proposals cover approval drawings only; others cover the full GFC set; some cover architectural GFC drawings but treat structural and MEP as separate consultant fees. Always confirm in writing which drawing stages are within the fee before signing the appointment. Ask specifically whether the fee includes GFC architectural drawings at 1:50 scale, structural drawings with BBS, and MEP layouts — or approval submission drawings only.
What is the difference between working drawings and approval drawings?
Working drawings is another term for GFC drawings — the fully detailed construction set. Approval drawings are the subset prepared specifically for the planning authority submission through TNOBPAS. Working drawings include everything an approval set contains, plus structural reinforcement details, MEP layouts, large-scale detail drawings and material specifications. The approval set is produced first; the working drawing set is developed from it as the project moves into detailed design and construction preparation.
What is TNOBPAS and how does it relate to approval drawings?
TNOBPAS — the Tamil Nadu Online Building Plan Approval System — is the state government’s digital platform for submitting building plan applications and receiving Planning Permission. It is the portal through which architects submit approval drawings for CMDA, GCC, municipality and other local body processing. The drawings submitted through TNOBPAS are the planning-stage documents; once Planning Permission is received, the project moves to the GFC drawing stage to prepare for construction.
What happens if I start construction before GFC drawings are ready?
Typically: columns placed without a confirmed structural grid, requiring correction or acceptance of errors; reinforcement specified on site by the contractor without engineering input; MEP conflicts discovered after concrete is poured; door and window openings cut to estimate rather than to a schedule; and a steady stream of variation orders as each missing decision is resolved under construction-stage pressure rather than design-stage consideration. The cost of a complete GFC drawing set is consistently less than the cost of the errors it prevents.
Planning Permission Is the Start of Construction, Not the End of Design
Talk to the team about what a complete drawing programme looks like for your Chennai project — which stages, which consultants, and when each set is issued.
Get the GFC set before construction begins
The Planning Permission from CMDA or GCC is a legal achievement — it confirms that your proposed building complies with TNCDBR development control regulations and that you may legally build. But it is the beginning of the construction process, not the end of the design process.
The GFC drawing set is what converts a legal permission into a buildable instruction. Without it, the contractor fills the information gap with site-level decisions. Some of those will be fine. Some will not be — and correcting them after concrete is poured is the most expensive kind of correction there is.
Confirm with your architects in Chennai exactly what drawing stages are within the agreed fee, and when each stage will be issued. “Is this a GFC drawing?” is one of the most important questions a Chennai homeowner can ask at the start of construction — and one that every professional design team should be able to answer immediately, clearly, and in writing.