Two buildings quoted at the same price per square metre can have completely different cost structures underneath. The ratio hides more than it reveals unless you know what's inside it.
Shell and core versus fit-out: two very different budgets
Shell and core, foundation, structure, envelope, roof, is comparatively predictable to price, because it's governed largely by area, structural system, and site conditions that can be assessed before design is finalised. Fit-out, finishes, fixtures, joinery, and the mechanical and electrical systems that serve the finished space, is where the real cost range lives, and it can vary by a factor of three or more between a basic and a high-end specification for the exact same floor area.
A quoted price per square metre without specifying which tier of fit-out it assumes tells a client almost nothing usable. Two quotes that look close on paper can represent a basic-finish shell-and-core-heavy number and a fully fitted high-end number that happen to land near the same figure by coincidence.
This is why the first real budget conversation on any project should separate these two numbers explicitly, rather than working from a single blended rate that obscures where the actual spending flexibility is.
The share MEP actually takes, and why it's often underestimated
Mechanical, electrical, and plumbing systems routinely account for a substantial share of total construction cost, often comparable to or exceeding the structural cost, yet they are the part of the budget clients think about least at the outset, because they are largely invisible in the finished building.
Underestimating MEP scope early is one of the most common causes of budget overrun, particularly when a project's ambitions for climate control, smart building systems, or specialised lighting grow between concept and construction drawings without a corresponding budget conversation.
The fix is simple in principle: price MEP as its own line item from the earliest realistic budget estimate, not as a percentage assumption carried forward from a different project's numbers, since the ratio shifts significantly with climate, building use, and system ambition.
What the ground hides from an early estimate
Foundation and substructure cost is disproportionately sensitive to information that usually isn't fully known until a geotechnical survey is complete: soil bearing capacity, groundwater level, and the presence of any previous structure or fill material on the site.
A site with straightforward soil conditions and a site requiring piling or extensive ground improvement can have a foundation cost difference large enough to shift the entire project's budget category, and that difference is invisible in an estimate based only on above-ground area and finish level.
This is why a geotechnical survey early, even on a small project, is one of the highest-value line items in a budget, it converts a genuine unknown into a priced risk before the number is relied on for financing or client commitment.
Contingency is not padding, it's pricing genuine unknowns
A construction contingency line exists to price the things that are genuinely unknown until construction is underway, conditions discovered once a foundation is excavated, material price movement over a project's duration, or a design detail that turns out to need more work once it's actually built.
Clients sometimes treat contingency as a number to negotiate down as far as possible, which usually just moves the risk rather than removing it, the unknowns don't disappear because the contingency line got smaller, they just show up later as unbudgeted change orders instead.
A contingency sized honestly to the project's actual risk profile, higher for renovation or unusual ground conditions, lower for a straightforward new build on well-understood soil, protects the budget far better than a token percentage applied uniformly regardless of project type.
A better question than 'what's the price per square metre'
A more useful early question is to ask for a cost breakdown by category, shell and core, MEP, fit-out, external works, and contingency, even as rough percentages, rather than a single blended figure. This makes it possible to see where a project's money is actually going and where there is real room to adjust scope if the total needs to come down.
It also makes different quotes genuinely comparable: two contractors quoting the same total price per square metre but a very different MEP-to-fit-out ratio are not offering the same building, even if the bottom line looks identical.
Asking for this breakdown early, before committing to a number for financing or planning purposes, is the single most useful thing a client can do to avoid the gap between an early estimate and the number a project actually costs once it's built.