News
13 Jul 2026
Across the City of London, many office buildings share a familiar architectural language: sleek curtain wall façades, large stretches of glazing and lightweight aluminium framing systems. These designs shaped much of the commercial development from the 1980s through to the early 2000s. Today, many of those same façades are quietly approaching, or have already exceeded, their intended design life.
Glazing systems rarely fail suddenly. Their decline is gradual, and the first signs are usually subtle: misting between glass panes, sealants beginning to harden, gaskets losing flexibility or recurring reports of draughts and water ingress. On their own, these issues may appear minor. Together, they often signal that a façade is entering a more vulnerable stage of its lifecycle.
In many cases, limited inspection or risk-averse advice can result in ageing façades being prematurely categorised as requiring full replacement, with significant implications for asset value and transaction outcomes.
As a façade consultant working across commercial portfolios, I increasingly hear the same question from owners and asset managers: how should ageing glazing systems be managed before they develop into more complex problems?
The first step is understanding how these systems age.
How curtain wall systems deteriorate over time
Most curtain wall systems installed in UK commercial buildings were typically designed with an anticipated service life of around twenty-five to forty years. Their longevity depends on the materials used, environmental exposure and the maintenance carried out over time.
Although many façades continue to perform reasonably well beyond this range, the components that keep the system weathertight and structurally reliable naturally degrade. Insulated glass units (IGUs) rely on edge seals (the perimeter seals that maintain the airtight cavity), which may fail over time. Sealants exposed to decades of UV radiation, heat and pollution can shrink or crack. Gaskets harden and lose the elasticity needed to maintain airtightness and prevent water ingress.
These are all typical age-related behaviours rather than unexpected defects, but they do indicate that the façade is entering the later stages of its service life.
Recognising the early warning signs
Interestingly, the first indicators of deterioration often show up inside the building rather than on the external façade. Tenants may report cold spots, inconsistent temperatures or draughts. Facilities teams may notice unexplained spikes in energy use or recurring incidents of water ingress. Fogging within glazing units is another common symptom.
These operational clues usually suggest that the façade is no longer performing as originally intended and that a more structured assessment is needed.
What a structured façade assessment involves
A façade assessment typically begins with understanding when the building was constructed, how the façade was designed and what maintenance has taken place over its lifetime. Façade engineers then carry out a visual inspection to identify cracks in sealant, areas where joints have failed or gaskets that are no longer seated correctly.
In some cases, intrusive checks are required to examine concealed elements such as drainage channels, glazing supports or structural sealant joints. This helps determine whether issues are isolated or whether they are part of a wider pattern of ageing across the façade.
Choosing the right intervention
The appropriate response depends on the extent of the deterioration and the building’s wider strategy.
Sometimes, localised repairs such as replacing failed glazing units or renewing specific sealant joints can extend the life of the façade at relatively low cost. Where issues are more widespread, a targeted refurbishment programme may be necessary to restore weather performance and improve thermal efficiency.
In many cases, well-planned refurbishment strategies can extend the service life of a facade by a further 10 to 15 years or more, depending on the underlying condition.
For buildings undergoing repositioning, sustainability upgrades or significant refurbishment, a full façade replacement can be the most effective long-term solution. Many owners are now choosing to upgrade façades to meet higher energy performance expectations and align with broader ESG goals.
However, full replacement is typically capital intensive, logistically complex and often difficult to undertake with tenants in occupation, frequently requiring vacant possession. By contrast, many repair and refurbishment interventions can be delivered on a phased basis, allowing buildings to remain operational.
Ageing façades and the wider asset strategy
Façade condition connects closely with other parts of the building, mechanical systems, energy use, sustainability targets and overall asset value. Managing glazing deterioration early helps prevent unplanned failures and allows owners to plan upgrades in a coordinated and cost-effective way.
A robust, evidence-led assessment can help ensure that decisions are proportionate – avoiding both premature capital expenditure on full replacement and the risks associated with underestimating underlying issues.
Looking ahead
As more commercial buildings reach or exceed their original twenty-five-to-forty-year design life, managing life-expired glazing systems will become an increasingly important issue for asset managers and owners.
The challenge is not simply identifying deterioration, but developing informed, proactive strategies that balance safety, performance and long-term investment priorities.
With structured investigation and timely planning, ageing glazing systems can be managed effectively, ensuring that the buildings which shaped the skyline of previous decades continue performing safely, efficiently and competitively for decades to come.
About the author
Sandra Sint is a façade engineer specialising in building envelope investigations, façade performance and technical due diligence. She works with commercial asset owners and investors to assess façade risk, ageing curtain wall systems and upgrade strategies for existing buildings.