Base date in construction contracts
A 'base date' is a reference date from which changes in conditions can be assessed.
The base date in construction contracts is generally used as a mechanism for the allocation of risk between the client and contractor for changes that might occur in the period between the contractor pricing the tender and the signing of the contract. This period can be very long and changes that occur may have a significant impact on the costs of the works.
The base date sets the reference date from which the conditions under which the tender was prepared are considered to have been known by the contractor and so are properly reflected in their price. If specified conditions change before the contract is implemented, then the contract may be adjusted to reflect this.
On very small projects, where the time frame is short, this may not be considered necessary. On larger projects, the base date can be used to allow changes to the contract sum, or sometimes extensions of time, or even to determine which rules will apply to the contract (for example which edition of arbitration rules).
The exact provisions will depend on the specific form of contract that is adopted. For example, in the Joint Contracts Tribunal (JCT) Design and Build Contract, the base date determines the allocation of risk in relation to changes in statutory regulations, changes to VAT exemptions and changes to definitions of dayworks.
Traditionally the base date was set as the date of tender, however this was sometimes found to give rise to uncertainty because of the complexity and duration of tendering procedures. The usual practice now is to insert a date in the contract linked to the date of the return of tenders. The FIDIC suite of standard conditions of contract (the Red Book and Yellow Book), set the base date at 28 days before the latest date for the submission of tender. The JCT Design and Build Contract suggests a date that is 10 days prior to the date of the return of tenders.
NB Fluctuation clauses are a way of dealing with inflation on large projects that may last for several years. The contractor may be asked to tender based on current prices and then the contract makes provisions for them to be reimbursed for price changes over the duration of the project (a fluctuating price). This may be done by setting a base date for specified items and defining the price indices by which fluctuations will be assessed. Fluctuation may allow for; changes in taxation; changes in the cost of labour, transport and materials; and even changes in head office or administrative costs.
 Related articles on Designing Buildings Wiki
- Completion date.
- Construction contract.
- Contract conditions.
- Contract sum.
- Extension of time.
- Liquidated and ascertained damages.
- Loss and expense.
 External references
EU-funded project launches a free online tool to help design energy efficient data centres.
Chinese building by Italian architect Joseph Di Pasquale that was a reaction to the skyscrapers of the west.
The CIOB launches its first code of practice for programme management.
In Sept 2016, two water management reports were published which should form the backbone of future management strategies.
Agreement announced for BSRIA to supply all on-site acoustic testing to NHBC clients.
If you are starting or returning to university for the new academic year, why not check out our wide range of resources?
From April 2017, non-households in England and Wales can choose their water supplier. What will this mean for the water sector?
An introduction to the historical development and methodology of value engineering.
Charles Drake’s concrete building apparatus met fierce resistance from the mainstream architectural establishment.
Recently given UNESCO World Heritage Site listing, Le Corbusier's modernist masterpiece Villa Savoye.
After IFA Messe 2016, what is the view on smart homes from Germany?
A snow-covered mountain peak designed by Oslo-based Reiulf Ramstad studio.
For more news, go to the home page.