When Structural and MEP Are Designed separately.

This is common in Chennai’s project delivery market, where each consultant is appointed separately and may never share drawings until construction has already started. This article explains where the conflicts come from, what they cost when discovered at different stages, and what to ask for before appointing a design team.

Our architects in Chennai manage the full drawing coordination process across architectural, structural and MEP disciplines for every project — because coordinated drawings are a fundamental delivery standard, not an optional extra.

The reason the two must be coordinated is straightforward: both occupy the same physical space. A structural beam is fixed once the concrete is poured. An HVAC duct must fit within the available void below the slab and above the finished ceiling. A plumbing riser needs a continuous vertical shaft from floor to floor. An electrical distribution board must be accessible and cannot be embedded inside a structural shear wall.

When structural and MEP designs are produced without reference to each other, these physical conflicts are almost inevitable — it is simply a matter of how many there are and how expensive they are to resolve.

The most common clash locations in Chennai residential and commercial projects follow a predictable pattern. Understanding them helps project teams prioritise coordination effort.

HVAC ducts in ceiling voids typically run horizontally at a fixed height below the slab. Where a structural secondary beam crosses a duct route, the duct cannot pass — unless it drops below the beam, reducing ceiling height in that zone, rises above it, which may not be possible, or routes around it. In a building with a regular structural grid there may be dozens of such crossing points. If the two drawing sets were never overlaid, every crossing point is a potential on-site problem.

Wet-area plumbing — drainage stacks, soil pipes, vent pipes — must run in continuous vertical shafts from the highest floor to the lowest. These shafts must be wide enough for the pipe diameters, access panels and future maintenance access. When columns or shear walls land in or adjacent to planned shaft locations, the shaft either has to be relocated or squeezed — sometimes to a size where the required pipes cannot physically fit.

Main distribution boards and sub-distribution panels require wall-mounted or recessed positions at accessible locations, typically on non-structural walls. Where structural shear walls are placed on the same faces where panels were planned, the panels must be relocated. Shear walls cannot be penetrated or modified without structural engineering approval — and even minor penetrations require verification. If the electrical design was done without reference to the shear wall layout, DB positions regularly conflict.

In a revised structural design — particularly where spans are extended, loads increased or concrete grade changed — beam depths frequently increase from the preliminary assumption. If the MEP design was based on an earlier, shallower depth, the increase can reduce or eliminate the available void, leaving insufficient space for the services designed to fit in it. This is one of the most common drivers of ceiling height reductions discovered during construction.

Electrical conduits must pass through walls and slabs — and where those are structural, any penetration must be approved by the structural engineer, properly formed and adequately reinforced. Where conduit routes are drawn through structural elements without coordination, either the conduit must be rerouted, adding length and complexity, or the structural element must be modified, requiring engineering verification and potential cost impact.

The honest answer is that drawing coordination requires deliberate effort, time, and a process that is explicitly managed — and in many Chennai project delivery arrangements, this effort is not included in any consultant’s fee scope.

• Consultants are appointed separately and at different times. The structural engineer is often appointed after the architect, and MEP consultants after the structural engineer. By the time MEP drawings are produced, the structural set may already have been submitted for building plan approval and is treated as fixed.
• No one is formally responsible for coordination. The structural engineer’s scope is to design the structure to carry the loads. The MEP engineer’s scope is to design the services to meet the building’s requirements. Unless someone’s scope explicitly includes coordinating the two sets — checking for clashes, issuing revised drawings, confirming resolution — no one does it.
• Drawings are reviewed in isolation. Each consultant presents their drawings to the architect or client independently. Without a combined overlay review, conflicts between sets are not visible.
• Approval drawings are too small-scale to reveal service conflicts. Drawings submitted to CMDA or GCC are at 1:100 — enough to confirm setbacks, FSI and layout, but not to reveal whether a 300mm beam conflicts with a 400mm duct. Detailed coordination can only happen at 1:50 or 1:20, which is the GFC drawing stage.

The cost of resolving a drawing conflict depends entirely on when it is discovered. The same conflict that takes one email to resolve at the design stage can require significant rework, material cost and delay if it is found after concrete has been poured or finishes applied.

Swipe or scroll to see the full table →

The question is not whether clashes will occur without coordination. They will. The question is whether they are found on paper or on site.

— Coordination is not an optional extra

A frequently asked question is whether structural and MEP should come from the same firm. The honest answer is that the critical factor is not whether they come from the same firm, but whether there is a clearly defined, actively managed coordination process — with one person or entity responsible for ensuring all discipline drawings are checked against each other before issue.

What effective coordination looks like

1. Defined coordination roleOne person or entity — typically the lead architect or a project manager — has explicit responsibility for managing the coordination process and issuing the combined coordinated set.
2. Regular multi-discipline drawing reviewsAt defined milestones, typically before each GFC issue, all discipline drawings are overlaid and reviewed together — not reviewed independently by each consultant.
3. Clash logA formal register of all identified clashes, their resolution status, and the revised drawings issued in response. The clash log is a living document, updated throughout design and construction.
4. Revision managementEvery revision that may affect another discipline is flagged to the relevant consultant immediately. Changes do not propagate silently — every change is tracked and coordinated.
5. Site supportThe process does not end at GFC issue. During construction the coordinator receives RFIs, coordinates the response across disciplines, and issues resolved drawings to the site team in a controlled, documented way.

Whether you are appointing a single architectural practice, a project management consultant, or separate discipline consultants, ask these before signing any appointment agreement:

Coordination is not an optional extra

The pattern of site changes, RFIs and cost overruns that characterises many Chennai construction projects is not primarily caused by bad contractors or difficult clients. It is caused by drawing sets that were never formally coordinated before construction began — sets where the structural engineer and MEP consultants produced technically correct designs that simply did not fit together in the physical space of the building.

The solution is not to use one firm for everything, though that can simplify coordination. The solution is to ensure that whoever is responsible for design delivery has an explicit, managed, documented coordination process for aligning structural and MEP drawings before any GFC set is issued to site.

Coordinated drawings reduce avoidable site conflicts. They reduce RFIs. They reduce variation orders. And they reduce the stress of discovering on site that two things that were both designed correctly do not fit together. Ask for a coordinated drawing set before construction begins — and if the design team cannot produce one, ask why, and what the process is for managing the conflicts that will otherwise be discovered on site.