Poor mobile signal inside a workplace is one of the most common complaints we hear, and it is rarely the fault of the phone. The good news is that there are several fixes, and the cheapest one is often already built into your team’s handsets. Here is how Wi-Fi calling works, where it falls short, and what else can help.
The 30-second version
- Buildings block mobile signal. Steel frames, foil-backed insulation, modern glass and basements are the usual culprits.
- Wi-Fi calling routes calls over your Wi-Fi instead of the mobile network, with no app needed on supported phones and networks.
- It only works as well as your Wi-Fi, so a weak wireless network gives weak calls.
- Other fixes include multi-network SIMs, a mobile-first phone system and approved indoor repeaters.
- The right answer depends on the building, and a short conversation usually identifies it.
On this page
Why signal is poor inside buildings
Mobile signal travels well through open air and badly through dense materials. Many modern and refurbished buildings are almost designed to keep it out:
- Steel frames and cladding, common in industrial units and newer offices.
- Foil-backed insulation, used to meet energy standards, which reflects radio signals.
- Energy-efficient glass, whose metallic coatings block signal as well as heat.
- Thick stone walls and basements, in older and converted buildings.
The result is familiar: full bars in the car park and nothing at the desk. Changing phones rarely helps, because the problem is the building, not the handset.
How Wi-Fi calling helps
Wi-Fi calling lets a mobile phone make and receive normal calls and texts over a Wi-Fi connection instead of the mobile mast. The phone uses the same number and the same dialler, so the person on the other end notices nothing different. On supported phones and networks there is no app to install. It is a setting in the phone.
The major UK networks support Wi-Fi calling on compatible handsets, and it is often the fastest and cheapest fix of all, because it uses equipment your business already has: the phones and the Wi-Fi.
Where Wi-Fi calling falls short
- It depends entirely on your Wi-Fi. If the wireless network is patchy, calls will be too. Good coverage in every room matters more than raw broadband speed.
- Moving between Wi-Fi and mobile can occasionally drop a call as someone walks out of the building.
- Not every tariff and handset supports it. Older phones and some plans do not, so it is worth checking each user.
- It does nothing outside your building, so it will not help staff who work on site or on the road.
Fix the Wi-Fi first
Wi-Fi calling exposes weak wireless networks quickly. If your Wi-Fi drops in meeting rooms or at the far end of the office, the calls will drop there too. A properly surveyed business Wi-Fi network is often the real fix.
The other fixes, compared
| Fix | Best for | Things to know |
|---|---|---|
| Wi-Fi calling | Offices and premises with good Wi-Fi | Built into supported phones; only as good as the Wi-Fi |
| Multi-network SIMs | Staff and vehicles moving through patchy areas | Uses the strongest available network; cannot help where no network reaches |
| Mobile-first phone system | Teams who need one number everywhere | A hosted phone system app on the mobile works over Wi-Fi or data |
| Changing network | Sites where one network is clearly stronger | We match each user to Vodafone, O2 or EE by where they work |
| Approved indoor repeater | Larger buildings with a stubborn dead zone | Must be an Ofcom-compliant model; unapproved boosters are illegal |
A word on signal boosters
Some mobile signal boosters sold online are illegal to use in the UK because they interfere with the networks. Ofcom permits only specific approved repeaters. If a repeater is the right answer for your building, make sure it is a compliant model.
Which fix is right for you
For most offices, the order is simple. Make sure the Wi-Fi is solid, turn on Wi-Fi calling, and check each user is on the right network. For teams who travel, add multi-network SIMs. For businesses that want one number for everyone wherever they are, a mobile-first hosted phone system ties it all together.
Dead zones in your building?
Tell us where the signal drops and how your team works. We will recommend the cheapest fix that actually solves it, whether that is Wi-Fi calling, a network change or something else.