A price per square metre presumes that an average project exists. In the residences we are speaking of, there is none: two villas of identical area, two kilometres apart, call for neither the same structure, nor the same authorisations, nor the same logistics. Publishing a range would reassure, and mislead. We prefer to say what makes a budget vary, and let each person place their own project.
The state of the fabric, which decides before all else
This is variable number one, and the only one that cannot be read on a drawing. An undersized floor, load paths that must be taken up, rising damp at the foot of a wall, ghost services buried in the masonry: none of this appears before stripping out and probing. It is also why we do not cost before surveying — a figure given beforehand is an opinion presented as a study.
Access, the item no one anticipates
At equal area and equal specification, two sites do not cost the same depending on how things reach them. The village of Èze is entirely pedestrian: everything goes up and back down by hand, through lanes and stairways. In Saint-Paul-de-Vence, the maximum size admissible intra-muros is set by the geometry of the two openings in the wall. Monaco stands on about two square kilometres, entirely built up, with no surface for site accommodation or storage: deliveries come in slots, never in bulk. On the Lérins islands, everything passes by sea. Cap-Ferrat is a cul-de-sac, and the lanes of the Cap are narrow, winding and lined with walls.
The regulatory framework, which is paid first in time
Depending on the regime, the same gesture does not require the same file. On an inscribed site, works altering the appearance of the place fall under a prior declaration; on a classified site, under a special authorisation from the prefect or the minister. In Nice, it is the safeguarding and enhancement plan of the Vieux-Nice, approved by decree of 17 December 1993, that governs works within its perimeter. In Monaco, the regime belongs to the Principality: a file signed by an architect registered with the Monegasque Order, examination by the Directorate of Forward Planning, Urban Development and Mobility, review by an advisory committee. That time is not neutral: immobilisation is a cost, even when no one is working.
What costs dear is almost never what is seen: it is what had to be done for it to hold.
Materials, and what they impose around them
A material does not cost only its purchase price: it imposes its environment. Solid stone is heavy, and that weight reappears in the floor that carries it. A veined marble presumes a choice made on the block, a drawn setting-out and a matching respected at laying. By the sea, the grade of the steel ceases to be a detail: less than five hundred metres from the shore, the atmosphere falls within corrosivity categories C4 to C5 of the ISO 9223 standard, and the A4 / 316L grade with molybdenum is required where an A2 / 304 would pit. Work done twice costs twice.
The number of trades, and the interfaces between them
A project is also paid for in coordination. Each additional trade adds not a line but interfaces: a point of contact between two crafts is a place where a dimension can be lost, where a provision can be missing, where a rework can be born. It is an item invisible on a quotation and perfectly visible on a schedule.
And what weighs less than one thinks
Floor area, precisely. Doubling the area of a project doubles neither the authorisations, nor the studies, nor the access constraints, nor the coordination. Conversely, a small intervention in a protected building, served by a lane and subject to authorisation, can mobilise everything a large site mobilises. That is why the question “how much per square metre” has no honest answer, and why we give none.
What we can say before surveying, on the other hand, is what we shall go and check, in what order, and at what point a figure will cease to be a hypothesis.
