Topographic Survey or As-Built – Which One Do You Actually Need?

When you’re planning or managing a construction project, it’s easy to get lost in the terminology. Two of the most commonly confused requests we hear from clients are: “We need a topographic survey” and “Can you provide an as-built survey?”

On the surface, they sound similar – both involve surveyors, data, and drawings. But in practice, they serve completely different purposes. Choosing the wrong one can waste time, money, and even cause disputes on site. Here’s a simple guide to help you ask for the right survey at the right time.

Getting the right survey at the right project stage – topographic before works, as-built after – helps avoid scope creep and costly mistakes.

What is a Topographic Survey?

A topographic survey (often called a “topo”) is carried out before construction begins. It maps the existing conditions of the land – including levels, boundaries, drainage, utilities, and features like ditches, kerbs, trees, or manholes.

This survey forms the base layer for design. Architects, engineers, and planners rely on accurate topo data to ensure drawings fit the site, gradients are workable, and risks are identified early.

Think of it as the “before” picture. Without it, designers are guessing – and that’s not something you want when building a highway, school, or housing development.

👉 For more on what’s included in a topographic survey, see the RICS guidance.

What is an As-Built Survey?

An as-built survey comes after or during construction. It records what has actually been built on site – kerb lines, drainage runs, piling positions, foundations, or entire road layouts.

The purpose is simple: prove compliance. Contractors, clients, and local authorities need evidence that the works match the design drawings, specifications, or planning approvals.

In some cases, as-builts are carried out in phases – for example, to sign off drainage before it’s covered up. They are also crucial for creating accurate asset records that will be used for maintenance long after the site team has gone home.

👉 The Highways England Specification for Highway Works sets out where as-built records are a contractual requirement.

The Key Difference

• Topographic = before, to design.

• As-Built = after, to prove.

It’s really that straightforward – but because the drawings can look similar, it’s easy for requests to get muddled. We’ve seen projects where a client asked for a “topo” halfway through works, when what they really needed was an “as-built” to confirm drainage installation.

Why Asking for the Right Survey Matters

Ordering the wrong survey isn’t just a paperwork issue – it has real consequences:

✅ Avoids scope creep – If you ask for a topo but really need an as-built, you may end up paying twice.

✅ Saves time – Engineers can deliver exactly what’s required the first time round.

✅ Reduces disputes – Clear records prevent finger-pointing when defects or delays arise.

✅ Improves compliance – Regulatory and contractual obligations are met with the correct deliverables.

👉 For a deeper dive into survey deliverables, read our post on Inspection Test Records (ITRs).

How to Decide Which One You Need

Here’s a quick checklist:

• Still in design stage? → You need a topographic survey.

• Finished (or nearly finished) building something? → You need an as-built survey.

• Unclear? → Speak to your surveyor – a quick call can save you days of wasted work.

At AKN Engineering, we provide both topographic and as-built surveys across Hertfordshire, Essex, Cambridgeshire, Suffolk, and beyond. By working closely with main contractors and sub contractors, we make sure you always get the right survey for your project – on time, first time.

📞 Need advice on your next project? Call us on 01279 927 033 or visit www.aknengineering.co.uk to get started.