Refurbishment and redevelopment of existing commercial building stock remain a steady source of work in major cities. Achieving improvements in building performance is becoming fundamental to the brief. Here is how it’s done.
According to recent market insights from global property experts JLL, commercial building investors are looking for sustainability credentials in their assets. This trend is generating significant opportunities for refurbishment works.
Besides adding value for owners, these projects create an opportunity to reduce operational costs and enhance amenity for occupants.
Where to Start
NABERS ratings for energy are based on a building’s energy consumption over a 12-month period. It is mandatory in Australia for most commercial buildings with a net lettable area of 1,000m2 or more to disclose the NABERS rating at the point of sale or lease.
Many commercial building tenants and real estate investors do judge an asset by its rating. The NSW Government, for example, will not lease spaces rated less than 5 Star NABERS.
Northrop Consulting Engineers Associate Ian Van Eerden says understanding how a building is going to be used post-refurbishment is essential. For instance, although NABERS ratings are a major driver for commercial building upgrades, the outcome is to create an efficient and comfortable space for people to work.
Van Eerden gives the example of a recladding project for a commercial building. While improving cladding quality will provide some “uptick” in value through better performance, it does not necessarily improve the quality of the space for occupants.
However, it is possible to look at such a project more holistically. A façade system that provides improved visual connection, thermal comfort, and access to fresh air can be of tremendous value to occupants.
Think About How Space Will be Used
Taking a step back and considering how a space is used and then thinking about what could be done to improve can expand minor refurbishments into a major repositioning of a project. It also affects design and specification decisions. Many smaller offices will locate desks next to windows, making floor-to-ceiling glazing a poor choice as it impacts privacy and drives up air conditioning loads.
“A builder needs to understand what different stakeholders want,” Van Eerden says.
It is also important to focus on more than simply aesthetics in terms of specifically requested upgrades. The project team also needs to consider the requirements of Section J in the most recent iteration of the National Construction Code. It sets out thermal and energy efficiency performance requirements, including façade and glazing performance and flow-on impacts that the changes may cause.
In general, a good refurbishment project is a “no longer like-for-like” replacement of worn out or outdated fitout or plant. There have been a growing number of projects where refurbishment is part of an adaptive re-use strategy, such as converting offices into apartments or converting industrial buildings into commercial co-working spaces.
Van Eerden says this is where an engaged project manager or builder can create a major project by thinking outside the box and turning a small project into a substantial one.
A Best Practice Refurbishment in Tuggeranong
Van Eerden is working on a project that is repurposing former Commonwealth Government offices in Tuggeranong in the ACT into a luxury aged care campus with a mix of independent and high dependency accommodation. The complex will also incorporate a cinema, grocery store, gym, and apartments.
Van Eerden says the developers, Cromwell and owners, Aspire, treated health of residence and energy efficiency as a priority from the start. They, therefore, focussed on the efficient delivery of thermal comfort within the building as there is a direct relationship with health outcomes.
Centralised HVAC was installed, as New Zealand statistics have shown that chronic cold or heat are key concerns for health in older people. When they live alone, they choose not to use HVAC for themselves, only heating or cooling when someone comes to visit. However, this tendency to endure thermal discomfort during hot weather or cold weather has massive impacts on health outcomes.
So by installing centralised HVAC, the project not only became more energy-efficient when compared to using individual systems, but it also ensures minimum temperature indoor conditions aligning to the World Health Organisation recommended temperature bands.
A “massive” solar array was installed to reduce power bills for the facility. Although this added to capital costs, operational energy costs are extremely low, resulting in lower outgoings for residents and the building owners, Van Eerden notes.
A Team Approach is Important
The type of contract model can impact how well a refurbishment project can address energy efficiency. Van Eerden says a traditional Design and Construct contract, for example, can be problematic if the contractor is driven primarily by the search for project cost-efficiencies instead of focussing on occupant amenity and building performance.
The Tuggeranong project took a team-based approach and had an overarching “purpose-driven” ethos. To ensure the project was on track in this regard, monthly reports were sent to the client on project outcomes, specifically around energy efficiency.
“We also all thought about our elderly relatives potentially living in the building,” Van Eerden says. “It made it much more personal and allowed us to consider comfort as a much higher priority.”
Cost savings to balance out some of the sustainability inclusions involved reusing the existing structure and the façade—measures that also yielded significant embodied carbon benefits.
Everything about the project had “quantifiable outcomes.”
The Basics are Simple
In general, improving energy-efficiency on any refurbishment project usually includes designing good passive systems and then specifying efficient mechanical systems, electrical systems and making sure things like insulation are well installed.
Builders and trades should “interrogate procurement” strategies to ensure the best products are provided and think about products in terms of a systems approach.
“For example, if you want a cheaper window, that might mean you have to increase the size of the roof plant to ensure cooling loads can be met. That, in turn, could mean you are losing space that could be used for other purposes.”
Get Everyone in the Room
To achieve this kind of systems approach, Van Eerden says, it is useful to get the subcontractors and consultants in a room together with the contractor during the early stages to talk through the options and how they affect each individual system or building element.
“Don’t just talk to consultants or subcontractors one at a time.”
BIM is also extremely useful to facilitate this approach. For an existing building, creating a BIM model “can pay for itself in no time,” Van Eerden says.
“Often there will only be drawings [of an existing building] from when it was first built, but no-one knows what changes were made to the building or what is actually in the walls. So, when it comes to a refurb, it can be anyone’s guess what you will discover.”
Energy Audits are Excellent Intel
It is also an excellent idea for a builder to do the building’s energy assessment during the tender phase. Talking to the building Facilities manager is a good place to start.
“An energy assessment is a goldmine of information.”
An energy upgrade plan can then form part of the tender response and project planning. The assessment will also be valuable if the client is aiming for a specific NABERS rating since the contractor may be required to provide a NABERS commitment plan.
“An energy audit is also providing value for the client. Even if the client is selling the building [after refurbishment], and especially if they are selling to a sophisticated investor, they will look at what is wrong with the building in terms of energy performance.”
When a refurbishment project gives a first-class result that attracts tenants or is sold for a premium price—the builder’s reputation also benefits.
A fundamental question for project teams is, “can I be proud of this project?”
“You are still the builder of record, even if the project gets sold, so make sure you are proud of your work.”