Modern building envelopes boost energy performance but block mobile signal. This piece explains how to plan an Ofcom‑compliant commercial booster + DAS, why Wi‑Fi calling is not enough, and how to document the solution to earn Wireless/Mobile points on the WiredScore pathway.

The unintended cost of great envelopes

Low‑E glass, foil‑backed insulation, steel frames and deep floor plates all attenuate outdoor mobile signal. The result is patchy voice, sluggish data and tenant complaints before fit‑out is complete. For buildings targeting certification, dependable cellular coverage now sits alongside digital resilience and Wi‑Fi as part of a complete user experience.

Why Wi‑Fi calling isn’t a complete answer

Wi‑Fi calling helps, but it depends on users joining the right SSID, maintaining QoS and trusting a public network. It doesn’t replace robust, multi‑operator cellular for tenants, guests and building operations. High‑performing projects deliver both: secure Wi‑Fi and reliable, in‑building cellular that “just works”.

DAS 101 for specifiers

  • Donor path: roof access, line‑of‑sight and isolation from in‑building antennas.
  • Cabling: low‑loss coax or fibre on long runs; coordinate routes with firestopping.
  • Antenna density: set by floorplate size, materials and target dBm levels.
  • Multi‑operator: one system supporting EE, O2, Vodafone and Three.
  • Commissioning: pre/post readings, acceptance criteria, handover pack.

Compliance matters

Under Ofcom rules only certain equipment and installation methods are legal. Grey‑import repeaters can cause interference and enforcement action. Specifications should explicitly require Ofcom‑compliant systems installed by qualified engineers with documented commissioning, this protects both client and contractor.

Documentation that earns points

Capture the whole journey: survey heatmaps, design rationale, as‑builts, test results and a maintenance plan. This evidence demonstrates an engineered solution and supports certification outcomes.

Budgeting & phasing

Allow time for rooftop permissions, riser access, night/weekend works and integration with other trades. Early surveys align expectations and prevent rework.

Next step

For a deeper look at how cellular coverage supports certification, see Wired score mobile signal.