Selecting a builder is the single most critical decision in any construction project to ensure that the team working on your property operates with industrial discipline, financial transparency and strict adherence to UK Building Regulations.
At Concept, our background in the Rail Industry has taught us that a project without a rigorous plan is a project destined for delays. Drawing on over 50 years of combined experience, here are seven technical tips to ensure you hire a reliable builder for your extension, renovation, or loft conversion.
1. Demand a Programme of Works, Not Just a “Start Date”
Most builders will give you a start date and a rough finish date. In professional construction, this is insufficient. You should request a detailed Programme of Works.
This document maps out the critical path of your project. It shows exactly when materials need to be ordered and when specific trades (electricians, plasterers) are scheduled.
- The Concept Advantage: Coming from a rail background, we apply high-pressure industrial logic to all domestic & commercial projects. We provide in-depth programmes allowing for constant tracking, ensuring that if a window delivery is delayed, the schedule is adjusted immediately to keep the project moving.
2. Understand Your Liability (CDM Regulations 2015)
Many homeowners in the UK are unaware that under the Construction (Design and Management) Regulations 2015, they are technically the “Client.” This carries legal responsibilities regarding site safety.
- Legal Checks: Ensure your builder explicitly agrees to take on the role of Principal Contractor. This transfers the legal duty for site safety, welfare, and coordination from you to them. A reliable builder will have a proactive health and safety policy, not just a first aid kit in the van.
3. Insist on a JCT Homeowner Contract
While a handshake or a simple email quote is common, it offers little protection. For significant projects, you should consider a standard form of contract, such as those provided by the Joint Contracts Tribunal (JCT).
A JCT contract is impartial. It clearly defines:
- Payment terms and schedules.
- Dispute resolution processes.
- What happens if the project runs over time.
- Specific insurance obligations.
4. Secure Your Investment with “Retention”
In commercial construction, it’s standard practice to hold back a percentage of the total cost (typically 2.5% to 5%) until the project is fully signed off. This is called Retention.
- How it works: You pay the final balance minus the retention amount upon practical completion. The retention is held for a “Defects Liability Period” (usually 3 to 6 months).
- Why it matters: It incentivises the builder to return and fix minor issues (snagging) that may appear after the settling-in period. If a builder refuses a retention clause, ask why.
5. Verify the “In-House” Claim
Delays often occur when a builder relies heavily on external subcontractors. If their usual plumber is stuck on another job in Dartford, your bathroom renovation in Rochester grinds to a halt.
- Our In-House Advantage: We operate with an “all trades in-house” model. From groundwork to roofing, our team is employed by the company. This allows for full commitment to your project and eliminates the “waiting for the sub-contractor” excuse.
6. The Technical Specification Dossier
Before signing anything, a reliable builder should be able to present a technical dossier. Do not proceed without verifying the following:
- Public Liability Insurance: Minimum £2 million (e.g. we hold £5 million).
- All Risks Insurance: Covers the structure and materials against theft or fire during the build.
- Building Regulation Compliance: Confirmation that an independent Building Inspector will sign off on stages (foundations, damp proof course, structural steels).
- Waste Carrier Licence: Evidence they can legally dispose of your demolition waste.
7. The Detailed Breakdown vs. The Estimate
Never accept a single-figure estimate. A professional quote separates material costs from labour, giving you transparency. Below is a comparison of what to look for:
| Feature | The “Estimate” (Avoid) | The “Fixed Quote” (Preferred) |
| Scope | Vague (“Build extension as discussed”) | Detailed line items (e.g., “Supply and fit 3x Velux GGL MK04”) |
| Price | Subject to change | Fixed for the scope of work defined with sensible clauses |
| Exclusions | Hidden or unmentioned | Clearly listed (e.g., “Decorating not included”) |
| Payment | “Cash as we go” | Scheduled payments against valuations |
| VAT | Often “forgotten” | Clearly calculated (Standard 20% or reduced rates for empty homes) |
Summary
Hiring a builder is about risk management. By insisting on a Programme of Works, a proper contract, and a retention clause, you filter out unreliable traders immediately.
At Concept, we pride ourselves on being straightforward, transparent, and efficient. We don’t just build; we manage the financial planning and logistics of your project from the first brick to the final coat of paint, ensuring your dream home in Kent becomes a reality without the nightmare.