How to Perform a Wireless Site Survey for Your Office

Poor Wi-Fi is one of the most common and most frustrating IT complaints in UK offices. Calls dropping in meeting rooms, dead zones near the kitchen, agonisingly slow connections at the far end of the building — these are problems that cost businesses real productivity and real money. Yet they are almost entirely preventable with proper planning. The key is a wireless site survey — a systematic assessment of your office environment that determines exactly where wireless access points should be placed, how they should be configured, and what coverage and performance you can expect.

Too many businesses skip this step, either deploying Wi-Fi based on guesswork or simply placing access points wherever there happens to be a convenient network socket. The result is predictable: patchy coverage, interference between access points, and performance that degrades unpredictably depending on how many people are in the office and what they are doing.

This guide explains what a wireless site survey is, how to perform one, what tools you need, and how to use the results to design a Wi-Fi network that actually works reliably across your entire office.

What Is a Wireless Site Survey?

A wireless site survey is a methodical assessment of a physical space to determine the optimal design for a wireless network. It involves analysing the building's construction materials, layout, and potential sources of interference, then using this information to plan access point placement, channel assignment, and power levels that will deliver consistent, reliable coverage throughout the space.

There are three types of wireless site survey, each serving a different purpose.

Predictive Survey

A predictive survey uses specialised software to model your Wi-Fi network based on floor plans and building characteristics without physically visiting the site. You import a scaled floor plan into the survey software, define wall types and materials, place virtual access points, and the software simulates the RF (radio frequency) propagation to predict coverage, signal strength, and capacity.

Predictive surveys are useful for pre-build planning — designing the Wi-Fi network before the office fit-out is complete — or for initial planning before a physical survey validates the design. They are quicker and cheaper than physical surveys but less accurate, because they rely on assumptions about building materials and cannot account for real-world interference sources.

Active Survey (Physical Survey)

An active survey involves physically walking through the space with a survey device — typically a laptop running survey software connected to a Wi-Fi adapter — while the access points are installed and transmitting. The survey software records signal strength, noise levels, and connection quality at every point as you walk, building a detailed heatmap of actual wireless performance across the space.

This is the gold standard of wireless site surveys because it measures real-world performance rather than theoretical predictions. It accounts for all physical obstructions, interference sources, and environmental factors that affect Wi-Fi in practice.

Passive Survey

A passive survey listens to all wireless signals in the environment without actively connecting to any network. It identifies all access points (including neighbouring networks), measures signal levels and channel utilisation, and identifies sources of interference. Passive surveys are often performed as a precursor to deployment to understand the existing RF environment.

What You Need for a Wireless Site Survey

Tools and Equipment

A professional wireless site survey requires scaled floor plans of the building (digital format, ideally DWG or PDF), wireless site survey software such as Ekahau, NetSpot, or iBwave, a laptop with a compatible external Wi-Fi adapter, a measuring wheel or laser distance measurer for calibrating floor plans, and a clipboard or tablet for recording observations about the physical environment.

For businesses performing occasional surveys, NetSpot offers a capable and affordable option. For IT professionals and managed service providers performing regular surveys, Ekahau is the industry standard, offering the most accurate predictive modelling and the most detailed active survey capabilities — though at a significantly higher price point (around £3,500 per year for a licence).

Information to Gather

Before the survey, gather information about the expected usage of the Wi-Fi network: how many users will connect, what devices they will use, what applications they will run (email and web browsing have very different requirements from video conferencing and large file transfers), whether there are specific high-density areas like meeting rooms or training rooms, and whether IoT devices or guest access will use the same network.

Performing the Survey: Step by Step

Step 1: Prepare the Floor Plan

Import your floor plan into the survey software and calibrate it — marking a known distance on the plan so the software can calculate scale correctly. Then classify each wall, partition, and structural element by its material type, as this dramatically affects RF propagation. A glass partition barely attenuates a Wi-Fi signal, while a reinforced concrete wall can reduce signal strength by 15 to 25 dB — effectively blocking it entirely.

Step 2: Conduct the Passive Survey

Walk the entire space with your survey device, recording all wireless signals in the environment. This identifies existing Wi-Fi networks from neighbouring offices or businesses, any sources of non-Wi-Fi interference (microwave ovens, Bluetooth devices, DECT phones), the noise floor in different areas, and existing channel utilisation across the 2.4GHz, 5GHz, and 6GHz bands.

Step 3: Plan Access Point Placement

Using the floor plan and passive survey data, plan the initial placement of access points. Key principles include placing access points in the centre of the areas they need to cover rather than at the edges, avoiding placement directly adjacent to thick walls or metal objects, ensuring adequate overlap between adjacent access points (typically 15 to 20 per cent overlap at the -67 dBm signal level for reliable roaming), using the 5GHz band as the primary band and 2.4GHz for coverage extension only, and placing additional capacity in high-density areas like meeting rooms and hot-desking zones.

Step 4: Deploy Temporary Access Points and Survey

If possible, deploy temporary access points in the planned locations and conduct an active survey. Walk the entire space systematically, following a path that covers every area where users will work. The survey software records signal strength and quality at each point, building a comprehensive heatmap.

Step 5: Analyse and Refine

Review the survey heatmaps and identify any areas with inadequate coverage (signal strength below -67 dBm for general use, or below -60 dBm for voice and video), excessive interference between access points, or dead zones. Adjust access point placement, channel assignment, and power levels as needed, then re-survey to confirm the changes have resolved any issues.

Signal Strength	Quality Rating	Suitable For
-30 to -50 dBm	Excellent	All applications including HD video and VoIP
-50 to -60 dBm	Good	Reliable performance for all business applications
-60 to -67 dBm	Acceptable	Email, web browsing, light cloud applications
-67 to -70 dBm	Marginal	Basic connectivity only — expect slow speeds
Below -70 dBm	Poor	Unreliable — frequent disconnections likely

Common Wi-Fi Survey Mistakes

Surveying an empty office: Wi-Fi performance changes dramatically when the office is occupied. People absorb and reflect radio signals, and their devices create additional traffic and interference. Wherever possible, conduct your survey during normal working hours with typical occupancy.

Ignoring the 5GHz and 6GHz bands: Many surveyors focus on 2.4GHz coverage because it travels further, but 5GHz and 6GHz are where modern devices achieve their best performance. Design for 5GHz as your primary band and treat 2.4GHz as a fallback.

Over-deploying access points: More access points do not always mean better Wi-Fi. Too many access points in close proximity create co-channel interference that actually degrades performance. Proper channel planning and power adjustment are more important than sheer quantity.

Forgetting about cabling: Every access point needs a network cable (Cat6 minimum) and, if using PoE, sufficient power from the switch. Plan cable routes early — particularly in older UK buildings where running cables through solid walls and ceilings can be challenging and expensive.

When to Hire a Professional

For small, straightforward office spaces — a single-floor open-plan office under 200 square metres — a basic DIY survey with a tool like NetSpot may be sufficient. But for larger offices, multi-floor buildings, buildings with complex construction, or environments with high-density or performance-critical Wi-Fi requirements (such as warehouses, healthcare facilities, or coworking spaces), a professional wireless survey is strongly recommended.

A professional surveyor brings not just the tools but the experience to interpret the results correctly, design an optimal solution, and configure access points for best performance. The cost of a professional survey — typically £300 to £800 for a small to medium office — is a fraction of the cost of poorly performing Wi-Fi and the productivity it destroys.