Preliminaries in Construction: The Complete UK Guide

Preliminaries often called “prelims,” “general conditions,” or “non-physical costs” - are the costs and requirements necessary to complete a construction project but are not tied to any specific work section. They encompass essential overheads such as site management, temporary works, health and safety measures, and regulatory compliance. In the UK, these are frequently referenced via the NBS (National Building Specification) classification system and integrated into JCT contracts as a separate section.

Importance and UK Context

All costs in a construction tender or contract will fall into one of two categories:

• Costs arising from specific work sections (direct costs).
• Costs required for the entire project (indirect costs, also referred to as preliminaries or general conditions).

Preliminaries describe the essential conditions and resources - beyond direct labour and materials - needed to ensure project-wide efficiency, safety, and regulatory compliance. They can be one-time or ongoing costs. In the UK, contractors often rely on JCT contracts (Joint Contracts Tribunal) to structure these prelims clearly, using standards like the NBS to streamline classification.

Why Preliminaries Matter for UK Contractors

• Transparent Tendering: By listing prelims separately, owners and contractors gain clearer visibility over which costs are tied to running the project as a whole.
• Clearer Project Scope: Prelims ensure that everyone - from project managers to site engineers - has a defined boundary of responsibilities and budget allocations.
• Enhanced Planning & Risk Management: Accurate prelims help contractors plan site access, environmental measures, and regulatory compliance before work begins, reducing unexpected overruns.
• Regulatory Compliance: The UK’s building regulations and safety standards can be strict; preliminaries account for onsite health and safety, environmental requirements, and any legal obligations.

Common Project Preliminaries

1. Management & Administration

These costs include payments to project managers, site managers, and other administrative staff who oversee the entire project rather than specific tasks. Listing these as preliminaries ensures transparency for both owners and contractors, clearly separating overheads from direct costs.

2. Site-Based Services

From access roads to site offices, temporary utilities, cleaning, waste disposal, and environmental controls, many services support overall site operations. This category also covers security measures and mitigating any disturbance to neighbours or adjacent structures.

3. Temporary Works

Temporary works - such as scaffolding, fencing, frameworks, and shoring - ensure safe and efficient construction environments. Though essential to the building process, they’re not part of the finished structure, making them a clear prelims item.

4. Mockups, Testing & Sampling

Designers and owners often require mockups to verify how finishes will appear. Typical testing and sampling procedures include concrete slump tests or lumber moisture checks, ensuring materials meet full-project standards. These costs are generally spread across the entire project rather than applied to a single work section.

5. Health & Safety & Environmental Compliance

Preliminaries must include PPE, site safety signage, first-aid facilities, environmental mitigations (e.g., erosion protection), and any UK-specific compliance measures. These ongoing costs protect workers, the environment, and satisfy construction regulations.

6. Other Project-Wide Costs

This category covers items like transport to and from the site, site-wide technology, administrative fees, and other overhead not attributable to a single task. Including them ensures no hidden costs absorb a contractor’s contingency.

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Construction Preliminaries Examples & Templates

When specifying preliminaries, contracts often reference NBS numbering or JCT contract structures. However, contractors may also use an ad hoc numbering system and text to fit the situation.

Here are two examples of preliminaries from projects in Australia and the UK:

• Griffith University
• World Museum Lighting Installation

A typical construction preliminaries template will include preliminaries for common aspects of a contract, including: 

• 00-05-10 Project Definition 
• 00-05-15 Works Terminology
• 00-05-20 Project Participants 
• 00-05-70 Project Location
• 00-10-70 Works Contract 
• 00-30-70 Works Contract Procurement
• 00-40-70 Works Contract Establishment
• 00-50-70 Works Contract Management
• 00-60-70 Works Contract Verification 
• 00-70-70 Works Contract Administration 
• 00-80-70 Works Contract Completion

Cost Allocation and Pricing for Preliminaries

Accurate estimating of preliminaries is critical for overall budgeting. In the UK, prelims can be priced in these main ways:

• Lump Sum: A single figure covering all overheads.
• Percentage of Contract Value: Usually 5%–15%, depending on the project’s scale, complexity, location, and duration.

A thorough, transparent breakdown helps prevent disputes, ensuring both contractor and owner understand the financial obligations inherent in running the project site.

Construction Contract Preliminaries vs. Preambles

The construction preliminaries breakdown - along with the work sections (activities and tasks) - should fully describe all that’s required to complete the project.

By contrast, the preamble registers the parties to the contract, summarises negotiations and tender procedures, and clarifies project objectives and standards. While the preamble sets the contract context, preliminaries detail the general conditions and site-wide requirements.

Final Thoughts

In UK construction, preliminaries (or prelims, general conditions) are non-physical costs that enable the smooth and compliant execution of a project. They include everything from administrative overheads and site-based services to temporary works and testing & sampling. Accurately pricing these items - often amounting to 5–15% of the total contract - supports transparent tendering, improves project planning, and helps mitigate risks.

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