Construction company: what happens between the drawing and the building

On a well-run site, the first thing you notice is not the concrete: it is the order. Reinforcement is stacked by diameter, circulation routes are clear, the teams are wearing their protection, a programme is posted up and somebody can answer the question "where are you up to?". None of that appears on a drawing, and yet it decides whether the building will come out of the ground on the terms announced.

Building is not designing

A construction company does not design the project: it carries it out. The distinction seems obvious; in daily practice it is not.

The designer defines what has to be achieved; the company decides how to achieve it. The choice of methods, the organisation of the site, the order of tasks, the human and material resources are its business. That is a skill in its own right, and it does not follow from the drawings.

A serious company also knows when a project is not its own to make. For new build, drawings prepared by a design professional are generally necessary, and a company offering to "do the drawings at the same time" to save time is exposing its client to risk rather than doing them a favour.

Depending on the arrangement, the company acts as main contractor — taking the whole and coordinating it — or on a separate package alongside other firms. These are not the same responsibilities nor the same organisation, and the contract must say which of the two applies.

The technical visit, before the quotation

A quotation drawn up without going to the site is an estimate in disguise.

The technical visit is there to see what the drawings do not show: access for lorries, the space available to store and set up, whether water and electricity are present, the real condition of what exists in a refurbishment, neighbouring constraints, the apparent nature of the ground. It is also there to measure what will be billed.

Some terms clients use as synonyms need separating here. An initial estimate is an order of magnitude. A quantity take-off is the schedule of works to be carried out. A quotation is a priced offer, item by item, based on that take-off. A contract price is what the parties committed to. Additional works are what is added afterwards, and unforeseen items are what nobody could see before opening up a wall.

What makes a quotation good is not its total but its legibility: what is included, what is excluded, the materials allowed for, the quantities taken, the labour, the timescales, and the conditions under which a price may change. Price levels, billing customs and applicable rules vary by country, by market and by contract: no general scale means anything here.

Preparing the site before opening the site

The preparation phase is the least visible and the one that recovers the most lost time.

It means setting up the site — fencing, access, storage areas, welfare facilities, water and power supply — establishing the task calendar, ordering whatever has long lead times, checking that the construction drawings are complete, and clearing up with the designer and the engineering office anything that is not clear.

An incomplete drawing discovered on the day of a pour is not resolved in an hour. Questions asked upfront cost minutes; the same questions asked mid-execution cost weeks.

Coordinating trades that get in each other's way

A building is put up by successive trades competing for the same space and the same calendar: earthworks, structure, masonry, roof structure and covering, plumbing, electrics, joinery, renders, finishes, painting.

The difficulty is not technical, it is temporal. A tiler who works before the plumbing is finished will do the job twice. An electrician arriving after the render will break the render. Coordination means sequencing, holding the trades in order, and arbitrating when two of them claim the same day.

Where part of the works is entrusted to other firms, responsibilities must be written down: who does what, over what scope, to what timescale, who checks, who answers for a defect. The legal regime of subcontracting, the main contractor's obligations and the remedies open to the client are not identical from one country to another. In the seventeen member States of the Organisation for the Harmonisation of Business Law in Africa, questions of company law, security interests and debt recovery fall under directly applicable uniform acts, interpreted by the Common Court of Justice and Arbitration — but construction law itself remains national.

Safety as organisation, not as a poster

This is the subject on which a company is judged fastest, and the one with the most explicit international framework.

Convention No. 167 of the International Labour Organization on safety and health in construction, adopted on 20 June 1988 and in force since 11 January 1991, applies to all construction activities — building, civil engineering, erection and dismantling — from the preparation of the site to the completion of the project, and may extend to self-employed persons as national law provides.

The ILO also adopted in 2022 a revised code of practice on safety and health in construction, updating the 1992 code and building on Convention No. 167 and its accompanying Recommendation No. 175. That text emphasises occupational safety and health management systems, risk assessment and the organisation of prevention throughout a project's cycle.

In practice, safety is read in the organisation: collective protection installed before individual protection, equipment provided and actually worn, circulation routes separated from work areas, controlled site access, work at height and scaffolding properly managed, temporary electrical installations checked, plant and lifting entrusted to trained people, tidy storage, legible signage, incidents recorded. The detail of the obligations depends on the country and the applicable regulations; the logic is everywhere the same: prevention is organised beforehand, not afterwards.

Materials: the right choice is local first

No material is best in the abstract.

The choice depends on local availability, delivered cost, climate, the construction technique adopted, the skills genuinely available in the region, the upkeep it will require, the durability expected and the applicable regulations. An excellent material that nobody can install properly produces a poor building.

The subject has gained a further dimension: the United Nations Environment Programme states that buildings account for around 37 per cent of energy and process-related CO₂ emissions and over 34 per cent of energy demand, and runs work on circularity approaches and the responsible acquisition of building materials. For a company, that translates first into simple habits: limiting waste, sorting and managing site waste, avoiding needless rework.

Billing what has been done

How a long project is invoiced is a matter of trust as much as of accounting.

The most defensible practice is to bill against observed progress, supported by a measurement the client can check, rather than against a theoretical calendar. A client who receives a valuation accompanied by the schedule of works carried out can verify it, if need be with their designer.

The terms — payments on account, retentions, due dates, financial guarantees — depend on the contract and the applicable law. They are discussed before signature, not when the first payment falls due.

Changes along the way

A client asking for an extra room, a different finish, a relocated opening or different equipment is within their rights. The professional failing is not accepting: it is answering "fine, we'll do that" without assessing anything.

A change may affect the structure, oblige other trades to come back, shift orders, alter cost and time, and in some cases fall outside the permission already granted. The professional method is to price it, state the effect on the calendar, check with the designer and the engineering office where the structure is involved, then have the decision recorded in writing before it is built.

A site that advances on verbal agreements always ends up producing a disagreement nobody can reconstruct.

Handover, defects and what comes after

Four things get confused and need separating: works that are finished, works that are in accordance with what was agreed, an apparent defect noted at delivery, and a defect discovered later.

Handover is the act by which the client takes delivery of the works. It is prepared for: what has been built is compared with what was described, defects are listed, a period is set to put them right, and each is checked off. A handover done in ten minutes with nothing in writing protects nobody.

What happens next — the length and scope of guarantees, any retentions, remedies in case of defect — depends entirely on the contract signed and the applicable national law. No guarantee period is universal, and a company that announces one should be able to say where it comes from.

What a construction company does not guarantee

A construction company does not guarantee that nothing unforeseen will happen, that an announced date will hold whatever the circumstances, that a budget will not move if the brief changes, that a permission will be granted, or that works designed by a third party are correctly sized. It stands in neither for the designer, nor the engineering office, nor the technical inspector.

What it does commit to can be checked: a technical visit before quoting, a legible quotation, a prepared site, a programme kept up to date, equipped teams, valuations backed by measurement, changes put in writing, an organised handover and documents handed over.

That is also what makes a company credible to a future client: a stable name and contact details, completed works presented for what they actually are, clean quotations and invoices, dated site photographs, a named point of contact, and the ability to show how a site was organised rather than promise that it will be.

This requirement is not reserved to large firms. Part of construction happens in loosely formalised settings, with tradespeople whose skill is not in question. What formalisation changes is not the quality of the work: it is the ability to prove what was agreed, to track what was paid, and to have poor work put right.

Finally, this article describes a trade; it replaces neither a study, nor a quotation, nor a technical opinion. The rules mentioned vary from country to country, and any real project is examined on the documents, with the qualified professionals where it is being built.