Understanding Quantity Surveying: A Guide for Homeowners

If you’re planning a home extension, loft conversion, or full refurbishment, you’ve likely heard the term Quantity Surveyor – but what exactly do we do? And more importantly, do you really need one?

The short answer: yes – if you want your project delivered on time, on budget, and without financial surprises.

At Reltic Construction Consultants, we specialise in residential cost consultancy, helping homeowners across London turn their building plans into successful, well-managed reality. In this guide, we’ll walk you through the role of a Quantity Surveyor (QS), why it matters, and how we can help make your next project smooth, transparent, and cost-effective.

What Is Quantity Surveying?

Quantity surveying is all about managing the financial and contractual side of construction. A Quantity Surveyor ensures that you, as the homeowner, understand the real cost of your project before a single brick is laid – and keeps things on track as work progresses.

Think of us as your financial partner throughout the building journey.

We measure, estimate, plan, and monitor construction costs from the initial concept through to final completion. Our goal? To protect your budget, manage risk, and make sure you’re only paying for what’s necessary and fair.

What Does a Quantity Surveyor Actually Do?

Here’s a breakdown of our key services—and how they directly benefit you:

📐 Cost Planning & Budgeting

We help you understand how much your project is likely to cost from the start. This includes everything from labour and materials to overheads and contingencies. No more guessing or underestimating.

📄 Bills of Quantities (BoQ)

We prepare detailed, itemised documents that outline every element of the build. These help you compare contractor quotes like-for-like and avoid hidden costs.

🛠 Contractor Tendering & Selection

Need help choosing the right builder? We manage the tender process, recommend trusted contractors, and evaluate pricing based on real data—not vague estimates.

📋 Contract Administration

We prepare formal contracts between you and your builder, setting clear expectations on timelines, payments, and responsibilities.

💰 Valuations & Payment Checks

Throughout the build, we assess what’s been done and approve payment requests—so you only pay for completed work, not promises.

🔍 Final Accounts & Cost Reports

At the end of the project, we review the final costs, reconcile any changes, and ensure the numbers stack up.

Why Homeowners Need a Quantity Surveyor

Many homeowners think a QS is only necessary on large commercial sites – but in reality, we add value to projects of all shapes and sizes. Here’s how:

✅ We Save You Money

By planning ahead, checking quotes, and preventing overspending, we often pay for ourselves in savings.

✅ We Reduce Risk

We spot problems before they become expensive. From unrealistic quotes to poor contract terms, we help you avoid the pitfalls.

✅ We Bring Peace of Mind

With a professional overseeing costs, you’re free to focus on the exciting part – bringing your vision to life.

Real-Life Example: Loft Conversion in South London

A recent client approached us with plans to convert their loft into a spacious en-suite bedroom. They had received three wildly different quotes and weren’t sure where to begin. We:

  • Created a detailed BoQ

  • Managed the tendering process

  • Helped select the most suitable (and fairly priced) contractor

  • Administered the contract and managed payments

  • Delivered a final cost report – on time and within budget

The result? A stunning new space and a stress-free experience for the client.

When Should You Hire a Quantity Surveyor?

The earlier, the better. Ideally, you should involve a QS during the design or pre-construction stage, especially if:

  • You’re unsure how much your project will really cost

  • You’re funding the build through a mortgage or loan

  • You’re managing multiple trades or contractors

  • You want full transparency and control over your budget

Whether you’re building up, out, or starting fresh, our role is to give you the numbers you can trust – so you can make informed decisions every step of the way.

What Makes Reltic Different?

At Reltic Construction Consultants, we focus solely on residential projects across London. Our service is tailored to homeowners who want professional guidance without the jargon or inflated fees.

✔️ Transparent pricing

✔️ Independent advice

✔️ Decades of industry experience

✔️ Trusted by contractors and architects alike

We speak your language and prioritise your goals – keeping your project grounded, realistic, and stress-free.

Final Thoughts

Hiring a Quantity Surveyor might seem like an extra step, but it’s one of the smartest investments you can make in your construction journey. From managing costs to reducing risk, our job is to protect what matters most – your budget, your time, and your peace of mind.

If you’re planning a home extension, loft conversion, or refurbishment project and want a clear plan with no nasty surprises, we’re here to help.

Ready to Talk Numbers?

📞 Get in touch with Reltic Construction Consultants for a free initial consultation.
We’ll show you how to take control of your budget—and your build.

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