One-Stage Tendering vs Two-Stage Tendering: Choosing the Right Procurement Route for Your UK Project

Choosing the right procurement route is one of the most important early decisions you'll make when planning building works. It directly affects your budget, the project timeline, the quality of the finished result, and your peace of mind throughout the process. For private homeowners, property investors, or business owners undertaking a residential extension, home refurbishment, or commercial fit-out, getting this wrong can lead to unexpected costs, delays, or disputes. At our Quantity Surveying and Project Management practice, we help clients navigate these choices every day, ensuring their projects stay on track.

What Does "Procurement Route" Mean?

In simple terms, a procurement route is the method you use to select and appoint your main contractor (or contractors). It determines how competitive the pricing process is, when the contractor gets involved, how much design information is available upfront, and how risks are shared between you and the builder. The two most common approaches for private clients in the UK are one-stage tendering (also called single-stage) and two-stage tendering. Both fall under broader procurement routes UK discussions, but they suit very different project needs.

One-Stage Tendering Explained

What it is: One-stage tendering is the traditional, straightforward approach. You provide contractors with a complete set of drawings, specifications, and tender documents, and they submit competitive fixed-price bids based on that full information.

How the process works step-by-step:

1. Your design team (architect, engineers, etc.) completes the detailed design and prepares tender documents.

2. You (or your Quantity Surveyor) invite 4–6 reputable contractors to tender.

3. Contractors review the documents, price the works, and submit bids (usually within 4–6 weeks).

4. You evaluate the tenders on price, programme, and quality criteria, then select the preferred bidder.

5. You sign a contract (often JCT Minor Works or Intermediate form for smaller private projects) and the contractor starts on site.

Best suited for: Simple, well-defined projects where the design is largely fixed and complete before tendering. Think straightforward residential extensions, loft conversions, or small-scale kitchen/bathroom refurbishments on standard properties with few unknowns.

Pros for private clients:

• Strong early cost certainty – you get competitive lump-sum prices upfront.

• Straightforward and familiar process.

• Can feel quicker to reach contract stage if your design is already ready.

Cons and risks:

• Limited flexibility – any design changes after tendering usually cost extra via variations.

• Contractor has no early input, so opportunities for buildability improvements or cost savings may be missed.

• If the design has gaps or site conditions reveal surprises (common in refurbishments), you bear most of the risk, potentially leading to claims or disputes.

• Programme implications: The overall timeline to site can be longer because design must finish first; contractors may build in higher risk premiums.

In our experience with residential construction advice, one-stage works well when you want simplicity and competitive pricing on predictable scopes, but it offers less protection if complexities arise.

Two-Stage Tendering Explained

What it is: Two-stage tendering involves an initial selection phase followed by a collaborative pricing phase. It allows early contractor involvement (often called ECI – Early Contractor Involvement) before the design is fully detailed.

How the process works step-by-step:

1. You prepare preliminary tender documents based on outline designs, site information, and high-level specifications.

2. You invite 4–6 contractors to submit first-stage bids covering preliminaries, overheads/profit percentages, method statements, and sometimes key rates or schedules of rates (usually 3–4 weeks).

3. You evaluate and select one (or sometimes two) preferred contractor(s) based on capability, approach, and commercial offer.

4. The selected contractor joins the team early to help refine the design, suggest value engineering, identify risks, and contribute buildability advice.

5. Together, you develop the detailed design and negotiate the second-stage price for the full works.

6. Once agreed, you sign the main contract and the contractor starts on site.

Best suited for: More complex or uncertain projects, such as commercial refurbishment project management, older property conversions, high-spec new builds, or works with tight programmes where overlapping design and construction preparation saves time. It's ideal when there are unknowns like structural conditions, listed building constraints, or phasing needs.

Pros for private clients:

• Early contractor input leads to more realistic pricing, better risk management, and fewer surprises.

• Develop a relation early with the contractor, you want to spend money on builders who you can trust.

• Greater flexibility to adapt the design as the project evolves.

• Improved collaboration often results in higher quality and fewer disputes.

• Potential for a faster overall programme by starting preparatory work and site mobilisation earlier.

Cons and risks:

• Less upfront cost certainty – the final price is negotiated in stage two, so strong management is essential to avoid escalation.

• The initial selection process takes longer, and you need trust in the chosen contractor.

• Requires active client or advisor involvement to control the second-stage negotiations.

Two-stage tendering shines in delivering better cost control and programme benefits for private clients facing complexity, as the shared approach reduces overall risk.

How a Quantity Surveyor & Project Manager Adds Value

Independent professional support from a Quantity Surveyor for private clients and experienced Construction project management team makes a significant difference, whatever route you choose. We prepare accurate cost plans and tender documents, manage the entire procurement process fairly and transparently, and provide honest & impartial advice on contractor selection. Throughout the project, we control budgets through regular valuations, identify and mitigate risks early, administer contracts to avoid disputes, and ensure variations are fairly valued. Our role is to protect your interests, acting as your advocate so you receive value for money, maintain quality, and keep the programme realistic.

When a project runs smoothly, the value of a Quantity Surveyor or Project Manager can go unnoticed. In reality, that level of performance is rarely achieved without expert oversight. We act as a protective shield for your investment and interests, ensuring the right decisions are made at the right time, preventing unnecessary delays, cost overruns, and programme extensions.

Seek Expert Guidance Before Deciding

Every project is unique, and the right procurement route depends on your specific goals, budget, timeline, and site complexities. Before committing, we strongly recommend discussing your plans with a trusted advisor. If you'd like an initial conversation about your upcoming residential or commercial project, feel free to get in touch – we're here to help you make confident, informed decisions that deliver the best possible outcome.