The retrofit maths on Johannesburg's ageing office stock

Payback periods, vacancy risk and what actually gets financed.

For most of the last decade the constraint sat somewhere else. Understanding why it has moved: and where it has moved to, is the difference between a strategy that survives 2027 and one that does not.

What is actually changing

Financial modelling across comparable projects puts the sensitivity in a narrow band. Move the discount rate by 150 basis points and the ranking of the options changes entirely, which is why the choice of reference case is doing so much quiet work in this debate.

The framework is workable. The assumption that the institutions can administer it at volume is not.

The evidence

Sector bodies report a consistent picture: demand for the service is not the problem. Converting demand into signed, financed, permitted work is where the pipeline narrows sharply.

What it means

For GEM's readers the practical implication is straightforward. Anyone with a capital decision landing in the next 18 months should be stress-testing their base case against a slower approval environment, not a faster one.

GEM will continue tracking this in our data journalism series. Corrections, additional data and counter-arguments from practitioners are welcome and will be published.