18% vacancy in London Grade B offices. 4% in Grade A. Same city. Same quarter. Two completely different markets. The flight to quality that started as a trend is now a structural reality — and Grade B stock is running out of time to respond.
Why Grade B Can't Compete
The problem isn't cosmetic. You can't solve this with a lobby refurbishment and new carpets. Grade B buildings face three structural disadvantages that worsen with each passing year:
- EPC ratings — most Grade B stock sits at D or E. After April 2027, buildings below EPC C can't be legally let. Upgrading a 1980s building to EPC C costs more than many are worth.
- ESG misalignment — corporate tenants with net zero commitments can't occupy buildings that actively increase their carbon footprint. Grade B buildings are a Scope 3 liability.
- Workplace experience — in a hybrid world, employees need a reason to commute. Strip lighting and ceiling tiles aren't it. Grade A buildings offer amenities, daylight, air quality, and the kind of environment that makes people choose the office over the sofa.
What Happens to the 18%
Three outcomes: conversion (residential, student, last-mile logistics), demolition and rebuild, or slow deterioration. The economics vary by location. Inner London Grade B has conversion potential. Suburban Grade B often doesn't. Some buildings will simply sit empty until the land value exceeds the building value, and demolition makes financial sense.
Frequently Asked Questions
Can Grade B buildings be viably upgraded to Grade A?
Sometimes — but only if the building has good structural bones, adequate floor-to-ceiling heights, and a location that justifies the investment. The upgrade cost typically runs £150-300 per sqft. Do the maths against local Grade A rents before committing.
Is this trend permanent?
Yes. The drivers — ESG regulation, hybrid work, valuation methodology — are structural, not cyclical. There will always be a market for value office space, but the definition of "acceptable minimum quality" has permanently shifted upward.
Until next time — keep the evidence closer than the deadline.
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About HermanWa
HermanWa is a building compliance and operations platform for property and facilities teams in the United Kingdom and Singapore, with portfolios across the Gulf. It keeps one auditable file per building — statutory deadlines, inspection evidence, contractor work, energy and carbon — and its AI assistant, Herman, answers questions about your buildings in plain English. HermanWa tracks obligations including fire risk assessments and fire door checks, Building Safety Act duties, Legionella (ACOP L8), EICR, gas safety and EPC in the UK, and SCDF fire certificates, Periodic Facade and Structural Inspections, lift permits and Green Mark in Singapore. Directors can check their exposure with the free Director's Risk Check.