A focus on quality, energy efficiency and flexibility are all growing trends, challenging our existing building stock to adapt and meet these new market needs. Approximately 90 percent of today’s buildings will still be in use by 2050, so successful adaptive re-use projects will play a critical role in achieving decarbonization targets for portfolios and cities. The Implementation of innovative high performance design strategies will be fundamental to their success.
Adaptive re-use projects are not only environmentally and socially responsible, they also make economic sense. They improve energy efficiency, present opportunities to increase commercial real estate, attract occupiers and sales from those who have aligned sustainability principles, and improve asset values.
However, not every building is suitable to be adapted to become taller and greener. In this article, our building systems, engineering and decarbonization lead, Marc Colella shares his insights and expertise.
“We’re seeing more and more demand to adapt existing buildings to not only make them taller but to reduce the amount of embodied and operational carbon. This is being driven by investment strategies, occupiers, policy decisions, global commitments and new priorities.
Before undertaking any project we start with an analysis to understand; how we can mitigate asset stranding, maximize commercial opportunities, existing constraints, planning envelope restrictions, technical compliance and statutory requirements. Then we look at the design of the building and consider five key elements:
1 Structural capacity
When analyzing the structural capacity of existing buildings, it is important to consider the gravity system, lateral system, as-built verification, and the design life of the future asset. The age of the existing building is critical to determine if any surplus structural capacity exists to minimize the extent of reinforcing works. For example, buildings developed in the late 1980’s to early 1990’s are good ones to target, as concrete technology advanced significantly during this period. However, engineers of that era did not have access to the computational optimization tools that we do today. Establishing certainty of the building’s as-built condition is vital and requires a systematic plan of both destructive and non-destructive investigation methods to determine that the existing building structural materials can support the intended design life of the proposed extension.
2 Vertical transport and universal access
Minimizing disruption and maintaining a continuous operation for existing occupants is often a key requirement, alongside the need to increase capacity, improve the lobby and arrival experiences and fulfil modern, universal access requirements. Implementing or reprogramming destination control lifts will improve performance within the existing building or complete upgrades to incorporate two lifts in one shaft could also be considered. However, these options can require consistent floor heights and a doubt height lobby which needs to be reviewed. Alternatively, the opportunity to build a new lift shaft adjacent to the existing building to service the new floors and create a unique experience for the high-rise occupants, is another option that can be considered.
3 Fire engineering
It’s vital to consider the existing fire evacuation strategy, the stair pressurizations and additional occupant load that will come with a taller building, particularly if the building will be occupied during the construction. Existing detection and alarms systems also need to be reviewed along with the water demand/pressure and flow. Existing booster systems may need to be upgraded and new risers may need to be required for the additional capacity.
4 Energy performance
It’s important to consider and understand the performance of the existing envelope and mechanical systems. Current energy rating tools do not cover this project typology, so a holistic approach needs to be adopted as if the whole building was new. The quality of the existing façade will be critical to determine if it can be reused to meet the energy performance metrics. The electrical infrastructure must be able to support full electrification such as photovoltaics and electrical vehicles. Adaptations will also need enhanced HVAC solutions and increased outside air.
5 Buildability
Adaptations often need to be undertaken in a live building environment under temporary conditions. We firstly seek to understand the existing core riser limitations, access restrictions, cranage and hoists locations and how to best access congested sites. In some situations construction staging could be necessary so the building services need to be designed in a manner to facilitate the various temporary conditions, or temporary plant could be required.