Preliminaries in construction
Contents |
[edit] What are preliminaries?
Preliminaries (or 'prelims') may form part of tender documents used to obtain bids for construction works or for the supply of goods or materials. Preliminaries provide a description of a project that allows the supplier (often a contractor or subcontrator) to assess costs which, whilst they do not form a part of any of the packages of works required by the contract, are required by the method and circumstances of the works. NBS suggest that 'the purpose of preliminaries is to describe the works as a whole, and to specify general conditions and requirements for their execution, including such things as subcontracting, approvals, testing and completion.' Preliminaries and work sections together describe what is required to complete the works required by the contract.
The costs attached to preliminaries may also be referred to as 'preliminaries' or 'prelims', or as 'site overheads', or general cost items or expenses. The Code of Estimating Practice published by the Chartered Institute of Building (CIOB) describes preliminaries as: '...the cost of administering a project and providing general plant, site staff, facilities, and site based services and other items not included in the rates.'
[edit] What might preliminaries include?
Preliminaries in tender documents might include:
- A general summary.
- Method statements.
- Pre-construction information.
- A description of any planning conditions or other conditions that may affect the works.
- A description of any outstanding statutory approvals that may fall to the supplier to satisfy.
- Party wall requirements or other agreements with, or rights of, neighbours (such as rights to light).
- Any emergency services obligations.
- A description of the reporting information that the supplier will be required to submit (often on a monthly basis) describing construction progress (including a detailed critical path programme, key performance indicators and earned value analysis). See Construction progress reports for more information.
- A description of the commissioning strategy, separating setting to work and balancing tasks from independent verification by the consultant team.
- Relevant reports (such as soil reports).
- An information release schedule.
- Quality management procedures.
- Labour relations.
- Schedules of mock-ups, testing and samples required from the supplier.
- The method of sub-contracting.
- Requirements for insurance, performance bonds, warranties and product guarantees.
- Requirements for the operating and maintenance manual.
- Requirement for progress photos to be taken on site during construction and off-site during fabrication.
- Dates for partial possession.
- Collaborative practices.
- Building information modelling (BIM) requirement and protocols (including requirement for BIM in sub-contracts).
- Site waste management plan.
- Contractor's site preliminaries, such as; staff, welfare provisions, site offices, plant, site waste clearance, water, electricity, furniture, ICT and consumables, rates, protection of work, protective clothing, site transport, setting out, building control fees, and so on.
NB: Preliminaries should not be confused with 'preambles' which set out things such as tendering procedures, that will not affect the contractor's price. For more information, see Difference between preliminaries and preambles.
[edit] Other definitions of preliminaries
According to NRM1: Order of cost estimating and cost planning for capital building work, main contractor’s preliminaries are; '...items which cannot be allocated to a specific element, sub-element or component. Main contractor’s preliminaries include the main contractor’s costs associated with management and staff, site establishment, temporary services, security, safety and environmental protection, control and protection, common user mechanical plant, common user temporary works, the maintenance of site records, completion and post-completion requirements, cleaning, fees and charges, sites services and insurances, bonds, guarantees and warranties. Main contractor’s preliminaries exclude costs associated with subcontractor’s preliminaries, which are to be included in the unit rates applied to building works.'
NRM1 defines ‘subcontractor’s preliminaries’ as; ‘…preliminaries that relate specifically to building work which is to be carried out by a subcontractor. Costs associated with subcontractor’s preliminaries are to be included in the unit rates applied to sub-elements and individual components.’
According to ‘Elemental Standard Form of Cost Analysis, Principles, Instructions, Elements and Definitions, 4th (NRM) Edition’ written by RICS in 2012 and published by BCIS, ‘the cost of preliminaries for the building being analysed should be stated and expressed as a percentage of the contract sum excluding preliminaries, contingencies and, where appropriate, contractor’s design fees.’
[edit] Related articles on Designing Buildings
- Bill of quantities BOQ
- Code of estimating practice
- Contingencies in construction
- Difference between preliminaries and preambles
- Form of tender
- Method statement for construction
- New code of estimating practice
- Overheads
- Preamble in construction contracts
- Pre-construction information
- Prime cost sum
- Profit and overheads on construction projects
- Provisional sum
- Subcontractor’s preliminaries
- Tender documentation for construction projects
- The difference between a prime cost sum and a provisional sum
Featured articles and news
What they are, how they work and why they are popular in many countries.
Plastic, recycling and its symbol
Student competition winning, M.C.Esher inspired Möbius strip design symbolising continuity within a finite entity.
Do you take the lead in a circular construction economy?
Help us develop and expand this wiki as a resource for academia and industry alike.
Warm Homes Plan Workforce Taskforce
Risks of undermining UK’s energy transition due to lack of electrotechnical industry representation, says ECA.
Cost Optimal Domestic Electrification CODE
Modelling retrofits only on costs that directly impact the consumer: upfront cost of equipment, energy costs and maintenance costs.
The Warm Homes Plan details released
What's new and what is not, with industry reactions.
Could AI and VR cause an increase the value of heritage?
The Orange book: 2026 Amendment 4 to BS 7671:2018
ECA welcomes IET and BSI content sign off.
How neural technologies could transform the design future
Enhancing legacy parametric engines, offering novel ways to explore solutions and generate geometry.
Key AI related terms to be aware of
With explanations from the UK government and other bodies.
From QS to further education teacher
Applying real world skills with the next generation.
A guide on how children can use LEGO to mirror real engineering processes.
Data infrastructure for next-generation materials science
Research Data Express to automate data processing and create AI-ready datasets for materials research.
Wired for the Future with ECA; powering skills and progress
ECA South Wales Business Day 2025, a day to remember.
AI for the conservation professional
A level of sophistication previously reserved for science fiction.
Biomass harvested in cycles of less than ten years.
An interview with the new CIAT President
Usman Yaqub BSc (Hons) PCIAT MFPWS.
Cost benefit model report of building safety regime in Wales
Proposed policy option costs for design and construction stage of the new building safety regime in Wales.
Do you receive our free biweekly newsletter?
If not you can sign up to receive it in your mailbox here.



























Comments
[edit] To make a comment about this article, or to suggest changes, click 'Add a comment' above. Separate your comments from any existing comments by inserting a horizontal line.
All of these “preliminaries” are quantifiable, so why should they be expressed as a percentage of the overall costs? This seems a lazy and sloppy way to calculate them, and not particularly accurate, and a licence to print money for the contractor.
In response to comment above: It's true that prelims are quantifiable after the event (eg. at final account) but the best a Contractor can do when tendering on a fixed price basis is make an appropriate allowance to cover the prelim costs it expects to incur. In doing so, it is left with the risk should it incur greater prelim expense during the execution of the works (save for instances like variations, where those costs arose due to factors outside of the Contractor's control). The approach proposed by the OP above would leave all the risk with the Employer and a Contractor could easily substantiate additional prelim costs if it were so inclined.