A WiFi site survey is only as good as the preparation before it and the handover after it. Most weak surveys fail on the inputs: a floor plan with no scale, no list of client devices, no access to the ceilings. The measuring itself is the shorter part of the job.
This checklist covers all three stages, so you can brief a provider or run a basic survey yourself. Where a figure comes from vendor guidance, we say so. Where a target is yours to set, we say that too.
What is the purpose of a WiFi site survey?
The purpose of a WiFi site survey is to learn how radio signal behaves in your building before you buy or change anything, so access points go where they meet your coverage and capacity needs.
Cisco describes a site survey as the first step in a WLAN deployment, used to assess radio behavior in a specific environment, and notes that many WiFi problems come from poor planning and coverage. It names three types. A passive survey only listens. An active survey measures with a client associated to an access point. A predictive survey is a software model with no field measurements. Our glossary defines the WiFi site survey and the predictive survey.
A survey ends in a design: how many access points, where, at what height, on which channels and power levels. It should also leave evidence you can check later.
Is a WiFi site survey worth it for a small office?
A WiFi site survey is usually worth it for a small office when the building has several rooms, mixed wall materials, more than one floor, voice or scanner devices, or existing complaints. A single open room served by one access point may need only a basic walk test.
The decision turns on the building and the devices, not on headcount. The costly mistake is cabling to the wrong positions. Cable is pulled to planned access point locations, so a wrong plan means pulling it again. A survey is cheap insurance against that.
The lighter option is a predictive survey from clean floor plans. Choose an on-site survey when the plans or wall materials are uncertain. Cost depends on area, floors, construction and deliverables, and Deploris quotes against a written scope. Our WiFi site survey cost guide explains the drivers.
- Worth it: more than a few rooms, thick or mixed walls, a second floor, voice handsets or scanners, meeting rooms with many devices, or users already complaining.
- Worth it: you are about to buy access points or order cabling and the positions are a guess.
- A basic check may do: one open room, one access point, laptops and phones only, and no complaints.
- Either way: measure again after installation, because a design is a prediction.
What should you prepare before a WiFi site survey?
Before a survey, prepare floor plans, a device list, your application needs and physical access, because the surveyor cannot measure what nobody has defined.
Scale matters more than people expect. Cisco notes that a survey map left at its default size is not calibrated, and that calibration cannot be fixed after the survey, which forces a new survey. Give the surveyor a plan with one known distance marked, or let them measure one on site.
- Floor plans: digital, one per floor, in PDF, CAD or image format, with a known scale and the current wall layout.
- Materials: drywall, concrete, glass, metal and fire-rated walls, plus floor and ceiling construction.
- Client devices: laptops, phones, tablets, scanners, printers and sensors, with the bands each supports. Your weakest device sets the target.
- Capacity: users and devices per area, meeting rooms, peak times, and the main applications such as video calls and cloud files.
- Roaming: the routes people walk while connected, such as corridors, stairs and warehouse aisles.
- Voice and scanners: handsets and barcode scanners need tighter targets than laptops.
- Bands: Cisco's planning checklist lists 2.4 GHz and 5 GHz. Say whether you plan to use 6 GHz too.
- Access: ceiling spaces, comms rooms, locked rooms, after-hours rules and who escorts the surveyor.
- Mounting constraints: ceiling type and height, landlord rules, where drilling is forbidden, power and PoE switch ports, and cable pathways.
- Known problems: where complaints happen, existing access points and a network diagram.
How do you do a WiFi site survey on site?
You do a WiFi site survey by walking the whole site at a slow, steady pace while measuring signal strength, signal-to-noise ratio, noise and interference, channel use, roaming and real speed in every area that needs service.
Cisco warns that walking too fast gives inaccurate readings, and that the scan list should include every channel in use or neighboring networks on unscanned channels go unseen. In an AP on a stick survey, a temporary access point on a pole is placed at the planned mounting height, then moved between candidate positions.
Cisco gives voice targets that show how specific a design target can be: a cell edge of -67 dBm, a signal-to-noise ratio of 25 dB (a noise floor no higher than -92 dBm at that signal), at least two access points heard at -67 dBm or better, and channel utilization under 50%. Its guide also recommends 15 to 20% cell overlap on 5 GHz and at least 20% on 2.4 GHz. Treat these as voice figures, not rules for every office. Set your own targets from your devices and applications.
Use the steps below as the field routine.
- Walk the building before measuring. Compare it with the plans and note walls, racks, glass, lifts and anything the plan misses.
- Mark every difference on the plan, so the model matches the building.
- Place the test access point at a candidate position and at the intended mounting height.
- Walk the area around it, including corners, stairwells, meeting rooms and the edges of the space.
- Measure with the device types your users carry, not only the survey tool.
- Record interference sources and neighboring networks.
- Adjust positions and repeat. Stagger access points across floors, because Cisco warns against stacking them directly above one another.
- Run speed tests at representative spots and walk the routes where people roam.
| Measurement | What it tells you |
|---|---|
| Signal strength (RSSI) | Whether a device can hear the access point well enough at that spot |
| Signal-to-noise ratio (SNR) | Whether the signal stands clear of background noise |
| Noise and interference | Microwave ovens, cordless phones, Bluetooth and other networks that reduce usable airtime |
| Channel use and overlap | Whether neighboring access points share channels and compete for airtime |
| Roaming | Whether a device can move to the next access point before it loses the last one |
| Speed tests | What users actually get in real spots, not only what the signal level suggests |
What should a WiFi site survey hand over?
A survey should hand over heat maps, access point positions with mounting details, a bill of materials, the channel and power plan, and the raw project file.
Ask for the project file. Cisco's validation guidance says to request the raw survey data files, so another engineer can check or reuse the work. Our glossary explains the heat map, and the Ekahau entry covers the tool many surveyors use.
- Heat maps: signal strength, signal-to-noise ratio, interference and capacity, each shown against your stated targets.
- Access point positions on every floor plan, with an ID, mounting height, orientation and mount type.
- Channel, transmit power and data rate settings. Cisco notes that disabling lower data rates shrinks each cell and reduces channel utilization.
- A bill of materials: access point models, antennas if external, brackets, cable runs and switch ports with PoE.
- The assumptions: survey date, devices and tools used, targets, and areas excluded.
- A cabling brief per access point, so structured cabling and certification follow the same positions.
- The raw survey project file.
Do you need a validation survey after installation?
Yes. A validation survey measures the finished network against the design, so gaps surface before users find them.
Cisco says a post-installation survey should confirm current coverage, whether it supports the design requirements, interference sources, equipment placement and rogue devices. It also lists checks on channel overlap for roaming, bleed-through from other floors and access point transmit power against what clients support.
Fix what the survey finds, then measure again. Keep the design and validation results together, so the next change starts from facts. A validation survey is also the first step when users report slow or patchy WiFi on an existing network.
How does Deploris scope a WiFi site survey?
Deploris scopes surveys against a written brief that names the survey type, the areas and floors, the access hours, the targets and the deliverables.
The brief covers the items in this checklist. At the end you receive heat maps, access point positions, a bill of materials and the project file. If installation follows, the cabling scope uses the same positions. We do not publish a price list, because a number without a scope would mislead. If you are unsure which survey you need, start with the predictive vs on-site comparison below, or contact us with your floor plans.
Key takeaways
- Prepare scaled floor plans, wall materials, a device list, capacity and roaming needs, and ceiling access before anyone measures.
- Measure signal strength, signal-to-noise ratio, interference, channel use, roaming and real speed, and walk the site slowly.
- Ask for heat maps, access point positions, a bill of materials and the raw project file.
- Validate after installation, because a design is a prediction.
- A small office with several rooms, mixed walls, voice devices or complaints usually gains from a survey.