Heritage buildings are nothing like what we’re building today. Many were designed at a time when traffic jams, roadworks and digital pedestrian crossings didn’t exist. Neighbourhoods were quieter and buildings had room to breathe.
These cultural assets reflect the historical narrative of a place. Some are protected by local or national bodies because of their architectural style and historical significance. Others may be considered a community’s cultural heritage even though they aren’t officially recognised.
What makes a heritage difficult to live in?
These are the most challenging issues from an acoustic perspective.
Lack of sound insulation
These buildings were often built before soundproofing techniques and materials were available. This means sounds from adjacent rooms, neighbouring properties and the street can easily permeate walls, floors and ceilings.
Hard materials and surfaces
Many heritage buildings include traditional materials like stone and timber, which tend to reflect rather than absorb sound. This creates echo and reverberation which can make interiors feel loud and uncomfortable.
High ceilings and open spaces
Large, high-ceilinged rooms and open-plan layouts facilitate sound and increase reverberation time. While great to look at and walk into, these features make it challenging to maintain a comfortable acoustic environment, especially for workplaces or homes where we value privacy and quiet.
Historic windows and doors
Original windows and doors often lack the seal or density of their modern equivalent, allowing external noise to penetrate easily. Retrofitting these, without compromising character, is challenging.
Restricted modifications
Regulations governing heritage buildings often limit what can be done to upgrade the acoustics. Alterations must respect historical integrity which may restrict adding soundproofing materials or altering the original structure. Consequently, achieving modern acoustic standards can be difficult.
What triggers acoustic upgrades in a heritage building?
Change in use
As cities grow and diversify, places and spaces change their purpose. Some buildings which once had an industrial use are transitioning to become apartments, hotels, offices and retail.
Change in external environment
When an area becomes more densely populated and the external environment around a heritage building changes – such as new roads, railways, bus stops, buildings or zoning – acoustic upgrades may be needed to protect the indoor environment from increased noise.
Hotels built some years ago, for example, are facing more external noise from surrounding streets, new freeway ramps and neighbouring towers with rooftop mechanical plants. They need to acoustically improve their facades to provide an adequate internal noise level for guests to sleep.
We’ve worked with a hotel in Sydney, Australia, to measure noise levels inside rooms at critical times, for example when guests are sleeping. We then recommended acoustic treatments for when the hotel operator’s recommended noise levels were exceeded with solutions ranging from double glazing to increase noise absorption level within the room.
Sustainability requirements
Several sustainability rating schemes incorporate acoustics as a part of their criteria and asset owners may need to upgrade their acoustics to maintain ratings.
These accreditation schemes emphasise acoustic quality:
LEED (Leadership in Energy and Environmental Design)
LEED includes credits for indoor environmental quality, with specific criteria for acoustic performance in categories like schools, healthcare and commercial interiors. These credits often focus on sound isolation, background noise levels and reverberation control.
BREEAM (Building Research Establishment Environmental Assessment Method)
BREEAM evaluates acoustic performance under its health and wellbeing category. Credits are awarded for minimising noise intrusion, ensuring sound privacy and managing internal acoustics.
WELL Building Standard
The WELL Standard has a strong focus on human health and wellbeing with an entire section dedicated to acoustics. It requires specific conditions for sound insulation, reverberation and noise management, especially in mixed-use and residential buildings.
Green Star
Green Star incorporates acoustics in its Indoor Environment Quality (IEQ) category – with requirements for wall performance, internal noise and reverberation time – rewarding projects that achieve optimal acoustic comfort for occupants.
New Zealand’s first 5 Star Green Star-certified hotel has been designed to the highest standards of sustainability for building and construction. Working closely with Cheshire Architects and Cooper and Company, we delivered the sustainability solutions that were a driving force behind the development.
NABERS
NABERS rates acoustics as part of indoor environmental quality. It assesses aspects like noise levels, sound insulation and reverberation. High NABERS ratings demand controlled acoustic environments.
Passive House
Passive House certification, while primarily focused on energy efficiency, also requires quiet indoor environments, particularly in residential projects.
Acoustic solutions
Some acoustic solutions require out-of-the box thinking, in particular when the facades can’t be altered and materials need to be retained.
Here’s a breakdown of key upgrades:
Sound insulation
Different uses come with different noise profiles and sensitivity requirements. A hotel or residential area, for example, needs robust soundproofing to protect guests from hallway and street noise. A mixed-use building, on the other hand, may need barriers between residential and commercial areas.
Upgrading walls, floors and ceilings with added insulation is often necessary to create the right acoustic separation for the building’s new purpose.
Flooring and beams
Heritage buildings can have thin timber floors. The noise of footsteps or dropping something can become an issue with the new use. Installing carpet, underlay, floor screeds or a floating floor can help reduce sound transmission between floors.
For the acoustic floor upgrades at the Hayman Kronfeld Building, Auckland, New Zealand, our client wanted to retain the existing heritage timber floors and beams and keep them visible. We achieved this by keeping the floors exposed above, installing treatment between the existing beams to improve the acoustic privacy between levels and control reverberation within the spaces.
Our team used exposed black novahush (a type of acoustic panel) for reverberation control and fire-rated plasterboard upgrades under the floor to improve Rw (weighted sound reduction).
Walls and internal partitions
Upgrading partitions to reduce sound transmission is essential if a building is transitioning use, for example industrial to commercial office.
For buildings exposed to new noise sources, retrofitting walls with added insulation, linings, studs or sound-dampening materials can reduce external sound transmission. In heritage buildings, this is sometimes achieved by adding internal layers, such as insulation panels or dampening membranes, while keeping the original facade intact.
Window and door retrofits
New roads or high-traffic areas can significantly increase ambient noise. If permissible, installing double or triple glazing, or specialised acoustic glass, can help mitigate unwelcome noise. In heritage buildings, secondary glazing is often preferred as it allows for improved sound insulation while still preserving the building’s exterior.
Doors may also need to be upgraded with seals or, if permissible, replaced with heavier sound-rated doors to better control noise.
We worked with a hotel in Sydney, Australia, to retrofit a second internal glazing layer to an existing window – creating an air gap between the two layers – improving overall acoustic performance without altering the facade.
Roof soundproofing
In cases where nearby developments increase rooftop or overhead noise – like from aircraft or tall buildings – roof insulation may need to be enhanced. Adding acoustic layers beneath the roof can help reduce noise transmission. This is often a simpler solution than structural changes.
Mechanical system noise management
To minimise the ingress of external noise through ventilation systems, adding acoustic baffles or installing high-density wrappings to mechanical ducts and units can help. This can be particularly useful if nearby construction or new roads increase low-frequency noises that travel easily through ventilation pathways.
Sound barriers or exterior landscaping
A holistic approach to acoustics will look at more than just technical solutions. Adding exterior elements like sound barriers or strategic landscaping, such as hedges or trees, can help deflect or absorb noise before it reaches the building. This is a subtle approach that can blend with the heritage setting, especially in areas with strict visual requirements.
Reverberation control
If internal spaces have large open areas or high ceilings, adding sound-absorbing materials to manage reverberation is essential. This is especially important in lobbies, dining areas or conference rooms.
Solutions might include introducing acoustic ceiling panels, wall treatments or even furniture designed for sound absorption. In some cases, low-level sound masking systems can help create a consistent background noise that reduces the perception of disruptive sounds.
Comfort and character
Planning these upgrades with heritage preservation is crucial as any interventions need to meet local regulations and respect the building’s character. In regions like the UK or Australia, which tend to have rigorous conservation standards, using minimally invasive methods and reversible modifications is often key to achieving effective acoustic performance without compromising the building’s cultural significance and value.
