Preliminaries

Preliminaries - often shortened to "prelims" on site - are the indirect costs in a construction contract that cover everything needed to set up, manage, and operate a project, without being tied to any specific item of physical work. They are the costs that enable the build to happen: the site office, the scaffolding, the project manager's time, the insurance, the health and safety documentation, and the temporary services that keep the site running from day one to final completion.

In UK construction contracts, preliminaries are typically listed as a separate section within the Bill of Quantities or schedule of works. They sit alongside, but distinct from, the measured work sections - the brickwork, the electrical first fix, the roofing materials. A contractor who prices measured work accurately but underestimates their prelims will find that the cost of running the site erodes their margin on the physical work.

What Goes into Preliminaries

The specific items vary by project type and scale, but a standard UK construction project's preliminaries section will typically include:

• Site setup and establishment: site office and welfare facilities (toilets, canteen, drying room), perimeter hoarding and signage, compound setup and storage areas
• Project management and supervision: site manager salary and associated costs for the duration of the programme
• Temporary works: scaffolding, temporary roofing, shoring, falsework, and other enabling structures
• Insurance and bonds: contractor's all-risk insurance, public liability, and any performance bonds required under the contract
• Temporary services: temporary water supply, electrical connections, and drainage during construction
• Site security: security fencing, CCTV, and out-of-hours security where required
• Health and safety: construction phase plan, welfare provision, site induction costs, and compliance with CDM Regulations
• Waste disposal: skip hire, segregated waste management, and licensed disposal of controlled materials

On a mid-sized UK commercial project, preliminary costs typically run at 10% to 15% of total contract value. On large-scale schemes with full-time resident site management, this can reach 20%.

Preliminaries in Tenders and Job Costing

When reviewing a tender return, the preliminaries section tells you whether a contractor has thought carefully about the project or put a lump sum at the top. A well-itemized prelims submission with each cost line referenced to the programme is a mark of a careful contractor. A single undifferentiated line for "site overheads" leaves you exposed to claims for additional prelims if the project scope changes.

From a contractor's perspective, accurately pricing and recovering preliminaries is a critical part of commercial management. Prelims can be recovered as a fixed sum, as a time-related rate, or as a combination. Whichever approach is used, the key is tracking actual prelim costs against the budget throughout the project - not just at final account stage. Cost overruns in the prelims section are often the first indicator that a project is running behind programme.

Zigaflow's job costing and project tracking tools support contractors in recording and monitoring preliminary costs against live jobs, giving commercial managers an early view of where prelim budgets are running ahead of the programme.