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Last edited 12 Oct 2022
Design and build procurement route
 What is the design and build procurement route?
Design and build is a procurement route in which the main contractor is appointed to both design and then construct the works described in the contract. This is as opposed to the traditional procurement route, in which the client first appoints consultants to design the development and then a contractor is appointed to construct the works.
Design and build can be seen as giving a single point of responsibility for delivering the entire project. Some clients, however, consider it is only appropriate for simple projects, where design quality is not the main consideration.
 How popular is the design and build procurement route?
The traditional procurement was historically the most commonly used procurement route, but there has been an increasing trend for contractors to take a more significant role in setting up projects, making appointments and managing the entire project process. This began with the introduction of design and build, which became popular in the 1980s.
Procurement trends survey, getting closer to your supply chain, published by Ryder Levett Bucknall (RLB) in March 2022, suggests that design and build is now the most commonly-used procurement route.
|Design and Build
|Traditional without Quants
|Traditional with Quants
|CM / MC
|Bespoke / Other
[Table published courtesy of RLB]
The employer gives potential contractors their ‘employer’s requirements’ setting out what they need from the project, and the contractors respond with ‘contractor’s proposals’, which include a price for the works.
The contractor can either be appointed to carry out all of the design work, or if the client wishes to have greater influence over the design, a concept design and outline (or performance) specification can be prepared by a consultant employed by the client, and then the contractor is appointed to complete the design and carry out the construction.
The contractor may use their own in-house designers to design the building, or they can appoint consultant designers, or the client's designers can be employed by the contractor to complete the design (either by novation or consultant switch).
Design and build contracts can be awarded on a fixed price, lump sum basis, but price certainty is then dependent on not making any subsequent changes as these could prove to be expensive (as prices charged by the contractor for those changes will not be subject to competition).
It is very important therefore that the client gives a great deal of consideration to the preparation of the employer's requirements, and if they have not appointed their own design team, they may wish to appoint independent client advisers to help them do this. Similarly, if any designers appointed by the client are novated or switched to work for the contractor, the client may then wish to appoint independent client advisers to review contractor's design proposals, administer the contract and monitor works on site.
 What are the different types of design and build?
There are two main types of design and build:
 What is single-stage design and build?
In the single-stage process the contractor is appointed under a single agreement to undertake the design and then construct the works. Single-stage tendering is used when all the information necessary to calculate a realistic price is available when tendering commences.
 What is two stage design and build?
In a two-stage process the contractor is first selected on the basis of a fee, preliminaries, overheads and profit. They then work with the design team (who may be employed either by the contractor or by the client at this stage) to develop the design, on the basis of which a fixed price is negotiated for the second stage; construction, when the design team may be novated to the contractor if the contractor does not already employ them.
 When should the design and build procurement route be used?
The design and build procurement route should be used:
- Where there is a need to make an early start on site – as design and construction can overlap.
- Where the client wishes to minimise their risk – as they have no responsibility for design
- For technically complex projects which can benefit from the contractor’s expertise in the design stage.
- Where the employer does not want to retain full control over the design development.
- Where the client wishes to have a single point of responsibility.
 What are the advantages of the design and build procurement route?
Advantages of the design and build procurement route include:
- A single point of responsibility for design and construction.
- Earlier commencement on site.
- Early price certainty.
- The benefit of the contractor’s experience during the design stage.
 What are the disadvantages of the design and build procurement route?
Disadvantages of the design and build procurement route include:
- The client may find it hard to prepare a sufficiently comprehensive brief to ensure the design meets their requirements.
- The client has to commit to a concept design early in the project development.
- Variations from the original brief can be difficult and expensive to arrange.
- It can be difficult to compare tenders and determine if they offer value for money.
- Ease of fabrication, speed and low cost may be prioritised by the contractor above aesthetic quality
See also: Design and build - pros and cons.
 What types of contract can be used for the design build procurement route?
Design and build contracts include:
- Joint Contracts Tribunal (JCT) DB 16 (also JCT Major project contract and JCT Constructing excellence contract).
- The Association of Consultant Architects ACA/2.
- Government Contracts GC/Works 1 (single stage or two stage) (NB: GC Works contracts are no longer being updated by the government).
- Institution of Civil Engineers (ICE) Design and Construct (this has now been withdrawn in favour of NEC3).
- The New Engineering Contract (NEC) Engineering and Construction Contract
NB: 'Develop and construct' is a variation on design and build, in which most of the design is completed before the contractor is appointed. This avoids some of the potential problems of design and build, but also misses some of the opportunities.
- Procurement route
- Procurement team
- Traditional contract for construction
- Contract notice.
- Contractor's design portion.
- Construction contract
- Design and build: outline work plan.
- Design and manage procurement route.
- Design Build Finance Transfer (DBFT).
- Design-Build Institute of America DBIA.
- Job order contracting.
- Procurement route options pros and cons.
- Project performance management.
- Two-stage tender
- Management contractor
- Maintenance contract.
- Employer's requirements for building design and construction
- Blyth & Blyth Ltd v Carillion Construction Ltd
- Construction contractor
- Fixed price construction contract
- Lump sum contract.
- Liability for building design.
- London Build 2020: Best Practice in Design and Build panel discussion.
- Employer's agent for design and build
- Design and build: tender
- Construction manager
- Renovate, operate, transfer (ROT).
- Single-stage tender
- Consultant switch
- Contractor's proposals for building design and construction
- Consultant team for design and construction
- JCT Construction management contract
 External references
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