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Navigating a construction project

17 November 2020



A construction project may appear daunting if you are unfamiliar with the process, and this short guide aims to provide you with some valuable information to prepare you for the construction phase of a building project (RIBA Stage 5), assuming that a JCT construction contract will apply. This guide is by no means comprehensive, however, and we have included some further reading at the end. If you have any questions, or do not understand anything in this guide, please do not hesitate to contact us.


You have been working with Hanslip & Company towards getting your project ready for construction, and we have probably just gone out to tender or you have sought a quote from a contractor. As part of these preparations, Hanslip & Co. as ‘Principal Designer’[1] will have complied pre-construction health and safety information for the contractor from the information you have provided[2] about your building.

Following return of the tenders/receipt of quotes, we may organise interviews of the contractors with lowest bids if the project is grant-aided or more complex.

When you are happy to appoint a contractor, we will write a letter of intent to them to signify your intent to enter into a building contract, and will organise a pre-contract meeting.

Musical Chairs – changing roles

At this point, you now become the ‘Employer’, and we will act as the ‘contract administrator’ in our capacity as Architect.

This means that we must be fair and impartial to both you – the Employer – and the Contractor, and mediate between your interests.

The most important thing is that all instructions and formal communications go through Hanslip & Co.. Ideally, you as the Employer will have a single point of contact.

We will be responsible for monitoring the progress of the Contractor, and for providing them information that they request in a timely manner. We will also be responsible for certifying the amount to pay the Contractor at regular intervals, from our own valuations of work complete or (if appointed) from valuations made by a Quantity Surveyor (QS).

You may also have appointed consultants such as a Structural Engineer, Mechanical and Electrical Engineer, Archaeologist, and/or Conservator who will be part of the ‘design team’.

As Principal Designer, we will also notify the Health and Safety Executive of the start date and duration of your project, and which companies/organisations are involved. This is accomplished through the ‘F10 Form’, which must be kept updated throughout the project.

Paying the Contractor

The Contractor will make an application for payment to the Quantity Surveyor (QS)/Hanslip & Co. by the ‘Interim Valuation Date’, which is usually monthly.

The Quantity Surveyor (or Hanslip & Co. if a QS not been appointed), will then value the work complete, including materials on-site for the works which are satisfactorily protected.

We will then issue an ‘Interim Certificate’ informing you of the amount which you should pay the Contractor, including any VAT, and less the retention.[3]

Payment must be made by you to the Contractor at least 21 Days after the Interim Valuation Date, which will be established in the construction contract.

Making changes and delays

At this point, making changes or delays will normally have cost implications, both in terms of additional materials, but also in the possible increase of the duration of the works. The Contractor’s day-to-day running costs (including hire of plant/tools/scaffold) – their ‘Preliminaries’ – may therefore be extended, and you will need to pay them for this extra cost.

All changes must be instructed to the Contractor by Hanslip & Co. in writing. This is known as an ‘Architects Instruction’.

If there is a delay to the Contractor’s programme, Hanslip & Co. will need to determine the cause, and award an ‘Extension of Time’ if the delay was not within the control of the Contractor.


When a building contract is established, there will be an agreed completion date, by which the Contractor must complete the works unless an ‘Extension of Time’ has been granted.

When Hanslip & Co. determine the work is sufficiently complete, we will issue an Interim Certificate stating that the project has reached ‘Practical Completion’. At this point you will pay the remaining amount due as valued, plus half of the retention which had been kept back at each previous Interim Certificate.

If an ‘Extension of Time’ has not been awarded, and the Contractor fails to complete on the date specified, Hanslip & Co. will issue a ‘Certificate of Non-Completion’, at which point any agreed damages become payable by the Contractor at the rate set in the contract. In practice, an informal arrangement might be reached by mutual agreement if all parties deem it is desirable.

The Rectification Period

Upon completion, the project enters RIBA Stage 6, and the ‘Rectification Period’ agreed in the contract begins. Hanslip & Co. will inspect the work for defects that have arisen over the course of this period at its end and will issue a ‘Rectification Certificate’ to instruct the Contractor to rectify the defects, if appropriate. Hanslip & Co. will issue a ‘Final Certificate’ when any defects are rectified, at which point any retention monies owed to the Contractor are paid, and the contract comes to an end.

Jargon buster

Architects’ InstructionA formal instruction to the Contractor to do something; typically used to make variations to the construction contract
CDM Regs / CDM RegulationsHealth and safety regulations governing construction projects
Contract AdministratorThe person empowered to administer the building contract; typically Hanslip & Co. in the capacity as Architect
Contract DocumentsThe documents forming part of the construction contract; typically the Specification, Schedules and drawings which describe and quantify the intended design/repairs
EmployerThe term used to describe the Client in a construction contract
Extension of TimeA period of time formally certified by the Architect to allow the Contractor more time to complete the works
F10 FormThe form issued to the Health and Safety Executive to notify them of the project; issued by the Principal Designer
Final CertificateThe certificate issued by the Architect at the end of the Rectification Period when any defects have been rectified
Interim CertificateA certificate issued by the Architect to the Employer – typically on a monthly basis – which states the amount to be paid to the Contractor
Non-CompletionIf a Contractor fails to complete by the date agreed in the contract, this is certified, and they may be subject to damages
Practical CompletionThe point at which the Architect/Contract Administrator deems that the works have reached a stage where they are complete, or very little of value is left to do
Principal DesignerThe lead designer who holds special duties to plan and collate health and safety information under the CDM Regulations; typically Hanslip & Co.
Quantity SurveyorA consultant formally appointed on larger/more complex projects to write a Quantified Schedule and to value the works during the construction phase
Rectification PeriodThe period of time (agreed in the contract) which ends with an inspection by the Architect to ‘snag’ (identify) latent (hidden) defects which arise during this period
Schedule of Work / Quantified  SchedulesA document which describes the quantities of work to be executed; typically listing constituent parts by location or trade
ValuationThe financial amount of complete work, including materials for the works on-site which are satisfactorily stored which will become due to the Contractor at that stage; assessed by the Quantity Surveyor (or Architect if no QS has been appointed)
VariationA change to what was agreed in the construction contract, including the contract documents

Further Reading

A short guide for clients on the Construction (Design and Management) Regulations 2015. Health and Safety Executive. Available at:


[1] The term ‘Principal Designer’ comes from the Construction (Design and Management) Regulations 2015 (CDM), which govern health and safety for construction projects.

[2] You have a number of duties under the CDM Regulations, including to provide relevant information.

[3] The retention is a percentage of the contract sum, specified in the contract, which is held back as a financial incentive for the Contractor to complete the works.