What Are Preliminaries in a Nigerian BOQ? A Complete 2026 Guide

"Preliminaries" appears near the top of almost every Nigerian Bill of Quantities, usually as one of the largest early sections, and is one of the most frequently misunderstood — often confused with mobilisation, which it overlaps with but is not identical to. This guide explains exactly what preliminaries covers, 2026 Nigerian pricing for its main components, and how to distinguish it from mobilisation, using the categories priced in our free Preliminaries Calculator.

What "Preliminaries" Actually Means

In quantity surveying practice, preliminaries (sometimes called "general items" or "general conditions") covers the costs of running the site and the project generally, as distinct from the cost of the physical construction work itself. It is the answer to "what does it cost to have a functioning, safe, properly managed construction site running for the duration of this project?" — separate from the cost of the blocks, cement, steel and labour that go directly into the finished building.

Preliminaries Components and 2026 Pricing

Beyond these items, preliminaries also draws on several rates shared with mobilisation — hoarding, signage, safety induction and PPE — since both sections deal with genuine site-running costs that overlap in practice, even though they are conceptually and often contractually distinct line items.

How Preliminaries Differs from Mobilisation

Mobilisation is specifically the cost of getting equipment, people and facilities onto the site and ready to begin — a largely upfront, one-time cost incurred at the start of the project. Preliminaries is broader and more ongoing — it covers the cost of running the site properly for the entire duration of the project, including items like ongoing site management time, safety compliance, and end-of-project waste clearance that mobilisation, by definition, does not cover. In practice, some contractors and some standard forms of contract bundle both under a single "preliminaries" heading; others separate them explicitly. Whichever convention your BOQ uses, confirm what is and is not included to avoid double-counting or, worse, leaving a genuine cost out entirely.

Worked Example: Preliminaries for a Medium Residential Project

A medium residential project running an estimated 20 weeks, with a workforce peaking at 12 people:

• Safety induction (12 workers): 12 × 30,000 = ₦360,000
• Permit holder registration (2 supervisors): 2 × 20,000 = ₦40,000
• First-aid kit and fire extinguishers: ₦30,000
• Site barricade (40m of exposed perimeter): 40 × 5,000 = ₦200,000
• Engineer/management time (2 days/week × 20 weeks × ₦40,000): ₦1,600,000
• Waste removal at completion: ₦80,000
• Demobilising transport (12 workers): 12 × 5,000 = ₦60,000

Total: roughly ₦2,370,000 for preliminaries on this project — a substantial figure that underscores why it deserves proper itemisation rather than a vague lump-sum percentage guess.

Common Preliminaries Costing Mistakes

• Applying a flat percentage of construction cost without checking against actual project duration. Some contractors price preliminaries as a rough percentage (commonly cited ranges vary widely) of total project value — this can significantly over- or under-price a project with an unusually long or short duration relative to its construction value.
• Double-counting items already in mobilisation. Confirm which section carries hoarding, signage and induction costs to avoid paying for them twice across two separate BOQ sections.
• Underestimating management time. Ongoing site supervision and management is often the single largest preliminaries cost on a longer project, and is easy to underprice if only physical items (barriers, first-aid kits) are counted.
• Forgetting end-of-project costs. Waste clearance and final site clean-up happen after the visible construction work is done and are easy to omit from an upfront budget focused on getting started.

Preliminaries in a Formal Bill of Quantities

In a professionally prepared Bill of Quantities following standard quantity surveying practice, preliminaries typically appears as its own distinct section, usually near the start of the document, separate from the measured trade sections (substructure, superstructure, finishes and so on) that follow it. This positioning reflects preliminaries' nature as a cost of running the project generally rather than a cost attributable to any single measured element of the finished building — it cannot be priced per square metre of wall or per cubic metre of concrete the way trade items can, since it scales with time and management complexity rather than physical quantity.

Some formal contracts price preliminaries as a percentage addition applied across the whole measured works total, recalculated automatically if the measured quantities change during the project; others price it as a fixed lump sum agreed at the outset, independent of any later quantity variations. Both approaches are used in Nigerian quantity surveying practice, and the choice affects how the client and contractor share the financial risk if the project's actual quantities or duration end up differing from the original estimate — a percentage-based approach shares that risk more evenly, while a fixed lump sum places more of the risk (and potential reward) on the contractor.

Frequently Asked Questions

Is preliminaries the same as mobilisation?

They overlap but are not identical — mobilisation is the upfront cost of getting set up on site, while preliminaries covers the ongoing cost of running the site properly for the whole project duration, including items mobilisation does not cover, like end-of-project waste clearance. See our Mobilisation Calculator for that side of the budget.

What percentage of total project cost should preliminaries be?

There is no single fixed percentage — it depends heavily on project duration, site complexity and workforce size relative to the total construction value. Building the figure up from actual project-specific items, as this guide does, is more reliable than applying a generic percentage.

Can preliminaries costs be reduced without compromising safety?

Some efficiency is possible through good planning — combining inductions, efficient management scheduling — but core safety items (first-aid provision, safety induction, adequate site management) should never be cut purely to reduce the preliminaries figure.

Should a homeowner on a small residential project worry about preliminaries at all?

Yes, though at a proportionally smaller scale — even a modest residential project needs basic site safety provision, some management time, and end-of-project clean-up, all genuine costs worth acknowledging explicitly in the budget rather than assuming they are automatically absorbed into the main contractor's quoted rates without separate consideration.

Does preliminaries cost appear as a single line or multiple lines in a typical Nigerian quote?

Practice varies by contractor — a more formally prepared quote following quantity surveying convention typically itemises preliminaries into its component categories, while a less formal residential quote may present it as a single combined figure, which is exactly why requesting a breakdown, as this guide recommends, is worthwhile regardless of how the quote was originally presented.

Does a larger project always have proportionally higher preliminaries cost?

Not in a strictly proportional sense — as covered in the companion budgeting guide on this site, several preliminaries components are close to fixed regardless of project size, meaning preliminaries as a percentage of total project cost is often higher on a smaller project than a larger one of similar duration and complexity.

Should preliminaries be discussed before or after agreeing the main contract price?

Ideally alongside it, as part of the same overall negotiation — treating preliminaries as an afterthought to be discussed only after the main works price is agreed removes an opportunity to negotiate the two figures together as a coherent whole, and can leave a client feeling ambushed by a significant additional cost late in the process.

Should preliminaries be reviewed differently for a coastal versus inland Nigerian project?

Site-specific factors like security risk, access difficulty and local wage rates can differ between locations and should be reflected in a location-specific preliminaries estimate rather than a generic figure applied regardless of where the project actually sits, similar to the regional variation discussed for material costs elsewhere on this site.

Can preliminaries cost be shared between a client and multiple contractors on a project with several trade packages?

On a larger project split across multiple trade contracts, some preliminaries items (site security, general site facilities) may genuinely be shared costs, and how this is apportioned between the client and each contractor should be clearly agreed in advance to avoid double-charging or, conversely, gaps where no one has budgeted for a shared item.

Is preliminaries cost typically higher for a rushed project than a well-planned one?

Often yes — a rushed project frequently sees inefficient sequencing, last-minute facility hire at premium short-notice rates, and reactive rather than planned management effort, all of which tend to push preliminaries cost above what a properly planned project of similar scope and duration would need.