Construction Claims

Our business is to help you with your construction claim.

Wilsons of Cambridge are experts in the preparation and analysis of all aspects of construction claims – these claims can include extensions of time, prolongation costs, disruption costs, acceleration costs and variations. We have many years of experience of construction claim preparation across a number of forms of contract including NEC, JCT, ICC and MF1. Through this experience, we have the knowledge and expertise to review what has happened on your project and then where required to help you prepare your claim for submission to your client.

Quite often, events occur which give rise to different claims, we can help you analyse these events and identify the causes and financial consequences.

There are a number of different types of construction claim, a brief explanation of each type is given below:

Extension of Time Construction Claim:

An Extension of Time claim (or EoT as it is often referred to), is a provision included in many forms of contract which allows the sectional completion date or final completion date to be extended to give the party more time to complete the work, whilst maintaining the contractual effectiveness of the liquidated and ascertained damages provision. The contract will have provisions which allow the completion date to be extended.

Typical events include:*

Exceptionally adverse weather conditions

Instructions for work variations


Deferment of possession of the site

Important to remember that an extension of time claim is usually for time only*

Prolongation Cost Construction Claim:

A Prolongation Cost claim allows a party, usually the Contractor, the right under the contract to recover the additional costs incurred from the client as a result of the completion date for the works being delayed. Often an extension of time has already been granted.

Typical additional costs incurred as a result of prolongation, may include cost for additional site accommodation, site running costs, plant costs, fluctuations and the like.

Disruption Cost Construction Claim:

Disruption claims and the costs that follow, are usually linked to resources and productivity – where the same quantity of work is undertaken but more resources are used to complete this work. These resources may be labour and or plant/equipment. It may also be the case, that the method of working is altered due to the cause of the disruption.

Delay (extension of time) claims and disruption are often linked and it is not uncommon for a delay event also to cause disruption. The approach to these claims are very different.

Acceleration Construction Claim:

If a client requests the work to be completed earlier than the contractual completion date, or as sometime occurs, the project has incurred some delays and the client wishes to accelerate the works to bring the completion date forward, this results in an acceleration claim.

Variations Construction Claim:

These are the costs associated with a change or variation in the scope of the client’s requirements, which has been instructed.

Depending upon the form of contract, this is state how the additional variation cost will be evaluated and paid. In return for this, the client receives the change it instructed.

To note:

It is important to note, that the approach to each of these claims will very much depend upon the standard form of contract used and what amendments have been made to this. With many forms of contract, the notices for these claims needs to be made at the time of the event or very soon after. The exact timescales will be given in your particular contract. In some cases, the claims may also be made jointly, for instance for a variation with an extension of time and prolongation costs.


Whilst the above refers to Client and contractor, these claims can also very easily occur between a contractor and sub-contractor.


*Always check your contract agreement for your actual rights.


We a professionally qualified staff, who have worked as Quantity Surveyors acorss a number of construction sectors. 

These include:

  • Buildings – refurbishment & restoration
  • Restoration and Conservation of historic buildings, listed buildings, churches and production of new stonework
  • Buildings – new buildings
  • Civil Engineering
  • Infrastucture Projects
  • Utilities including communications and fibre 
  • Civil Engineering in Rail Sector to Station Buildings, depots, structures and route upgrades


We are based in Cambridge, with fast broadband offices. Our experience covers projects throughout East Anglia, London & the South East and across the United Kingdom.

If you need help and assistance in claim preparation or you are on the receiving end of a claim, please contact us for more information of how we can help you:

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