What are preliminaries in construction? Costs explained

Published Friday 17 April 2026

Table of contents

• What are preliminaries in construction?
• Types of preliminaries in construction
• The importance of preliminaries in construction
• Preliminaries in a construction contract: essential components
• How to calculate preliminaries in construction
• FAQs on preliminaries in construction

Key takeaways

• Recognize that preliminaries are indirect, project-specific costs — such as site facilities, project management, and safety equipment — that support the entire build but don't appear in the finished structure, making them distinct from both direct construction costs and general business overheads.
• Itemise your preliminary costs rather than relying on a percentage estimate, especially for projects over £100,000, as this protects your profit margin, gives clients full pricing transparency, and reduces the risk of disputes or unexpected costs during construction.
• Categorise each preliminary cost as fixed, time-related, or project-specific so you can price accurately: time-related costs like site supervision will increase if the project runs longer, while project-specific costs like heritage site restrictions are easy to miss in bids.
• Include all preliminaries in your contract and quotes from the start, as omitting them leads to unplanned expenses that erode your margins and can damage client relationships when additional costs emerge mid-project.

What are preliminaries in construction?

Preliminaries in construction are the indirect costs required to support a building project from start to finish. They cover essentials like site facilities, project management, and safety equipment that don't appear in the finished structure but are necessary to complete the work.

These costs support the entire project rather than specific construction phases. Learn more about tracking project costs effectively.

Preliminaries share several key characteristics that distinguish them from direct construction costs:

• Cover the entire project: Support all construction phases from mobilisation to completion
• Remain temporary: Provide resources needed during construction but not part of the final building
• Include essential services: Encompass site facilities, management, and safety provisions
• Sit separate from work sections: Differ from direct materials and labour costs

Common examples include project management fees, on-site facilities, scaffolding, and temporary lighting.

Preliminaries can be fixed, one-off or ongoing costs. For example, you pay a project manager for the whole project, but an environmental assessment is a one-off fee. In a construction contract, preliminaries and work sections together describe the full project scope and all costs for each phase and the project as a whole.

Who calculates the preliminaries in construction projects?

The main contractor typically calculates preliminaries. They oversee all project components and can accurately assess total requirements across every phase.

Contractors handle preliminary calculations for several important reasons:

• Maintain complete project oversight: Understand all work phases and requirements
• Provide accurate cost assessment: Know site-specific needs and challenges
• Ensure bid competitiveness: Balance comprehensive coverage with competitive pricing

Develop your preliminaries to include everything needed for project completion. This ensures fair pricing and prevents costly surprises later.

Including preliminaries in your scope of work gives clients, contractors, and subcontractors a holistic view of the project. This helps you and your clients avoid unexpected costs later in the project.

Examples of preliminaries in construction

Preliminaries differ from business overheads. They're project-specific costs rather than general business operating expenses.

Preliminary costs fall into several common categories. Understanding these helps you estimate accurately.

Administration and project management costs cover the following activities:

• Managing project fees and coordinating teams
• Documenting quality assurance and tracking progress
• Communicating with stakeholders and ensuring compliance

Site setup and preparation includes these essential tasks:

• Installing temporary offices, toilets, and welfare facilities
• Connecting power, water, and utility services
• Setting up site access and security measures

Design and approvals involve the following activities:

• Refining designs and securing engineering services
• Submitting permit applications and obtaining council approvals
• Conducting surveys, assessments, and regulatory checks

Health, safety, and environmental compliance requires these provisions:

• Providing safety equipment and personal protective equipment (PPE)
• Developing and implementing safety plans
• Installing environmental protection measures

Usual percentage of preliminaries in construction contracts

Preliminaries vary significantly by project scope, duration, site conditions, procurement route, and contract requirements. They should be priced from project-specific information rather than relying on a fixed percentage.

Several factors affect how much you'll spend on preliminaries for any given project:

• Project complexity: Increases management costs for more intricate builds
• Project size: Justifies detailed cost breakdowns over simple percentages for larger jobs
• Location requirements: Raises setup costs for remote or challenging sites
• Regulatory demands: Adds compliance costs for public infrastructure projects

When to use detailed costing over percentages: For projects over £100,000 or those with unique site requirements, itemised preliminary costs provide better accuracy than percentage-based estimates.

Public infrastructure projects, bolstered by an anticipated £600bn in infrastructure investment over the next ten years, can incur greater preliminaries for regulatory compliance. Location also influences costs, as some sites require more preparation than others. Projects with higher risks need additional mitigation measures, which affects preliminary budgets.

Calculate your own preliminary costs to avoid undercharging, which is especially important given the ongoing decline in bank lending for construction companies. Take time to estimate and budget accurately. Construction accounting software can help you keep track of projects and costs so you can increase profitability.

Preliminaries and generals in construction

Preliminaries and generals is another term for construction preliminaries. It covers the general conditions and requirements necessary to execute a project, along with the associated costs.

Preliminaries combined with the work sections of a tender document outline everything about how the work will be completed.

Types of preliminaries in construction

Preliminaries fall into three main categories based on how they're structured and charged. Understanding these types helps you estimate more accurately and explain costs to clients.

Fixed preliminaries

Fixed preliminaries are one-time, lump-sum costs that don't change based on how long the project takes. You charge these once regardless of the project duration.

Common examples include insurance policies, initial site surveys, permit fees, and design services.

Time-related preliminaries

Time-related preliminaries are costs tied directly to the project duration. If the project timeline extends, these costs increase.

Examples include site supervision, equipment rental, temporary utilities, and ongoing security services.

Project-specific preliminaries

Project-specific preliminaries are conditional costs based on unique site requirements. These vary significantly between projects and are easy to miss in bids.

Examples include environmental controls, night work provisions, special access requirements, or heritage site restrictions.

The importance of preliminaries in construction

Preliminaries help prevent costly project disputes by providing pricing transparency and outlining all necessary support costs upfront. This aligns with the spirit of mutual trust and cooperation that modern contract frameworks like New Engineering Contract 4 (NEC4) emphasise.

Including preliminaries in your contracts offers several important benefits:

• Provide complete cost visibility: Help clients understand full project requirements
• Prevent disputes: Ensure all costs are agreed before work begins
• Support project success: Reduce delays and scope changes through proper planning

Omitting preliminaries carries significant risks. Failing to budget for project-wide support costs can lead to unplanned expenses and erode your margins. When you don't budget for essential services like site facilities, lighting, and project management, additional costs emerge during construction.

Properly managing your preliminaries can contribute to project success. You're less likely to face disputes later if you cost and present all items upfront. This can also help prevent project delays that occur when you pause work because the scope changes.

Preliminaries in a construction contract: essential components

Preliminaries are industry standard for transparent project pricing, though not legally required.

Clients typically expect to see certain items in your preliminaries. These standard components help them understand the full project scope:

• Project management: Administration and coordination services
• Site preparation: Setup, facilities, and utility connections
• Design services: Plans, approvals, and regulatory compliance
• Safety compliance: Health and Safety Executive (HSE) requirements and risk management

Excluding preliminaries makes pricing uncertain and can damage client relationships when additional costs emerge during construction.

For a construction preliminaries template, visit the Royal Institute of Chartered Surveyors (RICS) new rules of measurement. These documents help you estimate costs and identify what counts as a preliminary. You can customise the templates for your own construction contracts.

To track expenses and monitor project progress,accounting software for construction helps you deliver projects on time and within budget. Explore our guides covering all aspects of managing your construction business for more tips.

How to calculate preliminaries in construction

Calculating preliminaries accurately protects your profit margin and ensures you can deliver the project successfully. Follow these steps to develop comprehensive preliminary estimates.

1. Review the full project scope and site conditions: Understand the unique requirements of the build.
2. List every support cost required: Document all necessary facilities, equipment, and management tasks.
3. Categorise costs as fixed or time-related: Separate one-off expenses from ongoing costs.
4. Research current market rates: Get quotes from suppliers and subcontractors for accurate pricing.
5. Add contingency for project-specific risks: Include buffer amounts for unexpected requirements.
6. Review and validate your estimates: Check calculations and ensure nothing is missed.

FAQs on preliminaries in construction

Here are answers to common questions about preliminaries in construction.

What's the difference between preliminaries and overheads?

Preliminaries are project-specific costs required to support a particular build, such as site facilities and project management. Overheads are general business expenses like office rent and administration that apply across all projects.

Who pays for preliminaries in construction?

The client pays for preliminaries as part of the overall project cost. They're typically included in your quote or tender and form part of the contract sum.

Can preliminaries be reduced to lower project costs?

While you can look for efficiencies, cutting preliminaries too much risks project success. Essential items like safety equipment, site facilities, and adequate management are necessary to complete work properly and safely.

How detailed should my preliminaries breakdown be?

For projects over £100,000, provide an itemised breakdown. This gives clients transparency and protects you if costs increase. For smaller projects, a summary may suffice.

What happens if I underestimate preliminaries?

Underestimating preliminaries erodes your profit margin as you'll need to cover the shortfall. In some cases, you may need to negotiate additional payment with the client, which can damage relationships and delay the project.