what are the considerations for soundproofing in a garage granny flat2

What Are The Considerations For Soundproofing In A Garage Granny Flat?

Do you want to convert your garage into a granny apartment but are worried about the extra noise? The best way to guarantee a quiet and relaxing home environment is to soundproof it. Understanding the intricacies of soundproofing in a garage granny flat is vital whether you intend to live in it with a family member or rent it out.

Insulate the garage's walls, floors, and ceilings to keep unwanted noise out and your privacy intact. Using the right insulation materials and methods is crucial to this end. To assist you in building a peaceful and soundproofed room that works for you, we'll be going into greater detail in our next post about the materials, tactics, and expert advice you may use. However, these are just some things to consider while soundproofing a granny flat in the garage. Come along as we delve into the specifics that can make or break your attempt at establishing a tranquil sanctuary in your garage.

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    Garage Comprehension Tiny House

    A garage granny flat, often called a garage apartment or an auxiliary dwelling unit (ADU), is a small, detached residence attached to or built into the garage of a primary residence. These structures are intended to be autonomous from the main home yet are frequently located on the same lot. Several factors have contributed to their rising popularity:

    1. Additional Living Space: Homeowners can gain additional living space from a garage granny flat without having to make major structural changes to the main house. For example, you may utilise it to house your extended family, guests, or renters.
    2. Rental Income: Many homeowners are opting to construct garage granny flats to supplement their income. These apartments can be rented out to people looking for stable supplemental income.
    3. Increased Property Value: Installing an accessory dwelling unit (ADU) can raise the market value of a home. Potential purchasers will be attracted to the home more, and the home's value may rise as a result.
    4. Multigenerational Living: Today, many families have multiple generations living under one roof, making garage granny flats a practical option. They provide an independent living option for seniors, adult children, or other family members who still value their privacy and independence.
    5. Affordable Housing: Garage granny flats can be cost-effective for individuals or small families seeking shelter in high-priced real estate markets. When compared to the cost of renting a similar-sized house, they tend to be more affordable.

    Common Uses Of Garage Granny Flats Include

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    1. Guest Accommodation: These units are perfect for entertaining guests or friends of the homeowners, as they offer both seclusion and convenience.
    2. Rental Income: Renting a garage granny flat can create passive income for a homeowner.
    3. Home Office or Studio: To have a dedicated, peaceful location for work or creativity, many people transform their garage granny flats into offices, art studios, or workspaces.
    4. In-Law Suite: These apartments are ideal for in-law suites for elderly parents or relatives, allowing them to maintain independence while remaining close to loved ones for socialisation and care.
    5. Short-Term Rental: Some homeowners have begun renting out their garage granny flats on short-term rental websites like Airbnb to generate extra income.
    6. Housing for Adult Children: Those adult children who have moved back in with their parents or who are saving money for their own property can live independently in the garage granny flat.

    Types of Granny Flats

    Did you know that there are numerous configurations for granny flats? There are many reasons why people prefer to create granny flats, and contrary to common belief, they come in various designs. Over our seven years as a leading Newcastle granny flat construction company, we have seen the range of options available to our clients firsthand.

    Detached Granny Flat

    A detached granny flat is a secondary living unit that is physically separated from the main house on a property. Since a detached granny flat can have its entrance and, in most cases, a fence separating it from the main house, it can be an excellent investment vehicle.

    Attached Granny Flat

    A granny flat attached to your main house is built to look like it has always been there. Depending on how we face the granny flat, we can isolate you from the neighbours or force you to spend more time with them.

    Granny flat with Garage

    Did you know a garage might be included in constructing a granny flat? You certainly can! A granny flat with an interior area of 60m2 is allowed by the State Environment Planning Policy (SEPP). An attached garage is not considered part of the habitable area of a granny flat because of its non-residential status. A completely enclosed garage (or carport) can be added to your granny flat without reducing the overall footprint. Accessing the garage from the inside is a great option on wet days.

    Two-Story Granny Flat

    Two-story granny flats are gaining popularity as more people see the financial and practical benefits of having one in their garden. Two-story granny flats can be any size or design, but like their one-story counterparts, they can be at most 60 square metres of interior living area.

    Detached Studio

    A detached studio is a separate facility that can be utilised for a variety of reasons other than its primary function. Even though it is physically distinct from the main house, a studio granny flat is still part of the household. This type of granny flat can also be constructed in a BAL40 or Flame Zone.

    This is not a secondary residence, as it needs a kitchen and a washing room. A studio granny flat is a perfect solution if you work from home and need more space, whether for an office or for a family.

    Soundproofing: How Does It Work?

    Soundproofing can be used to reduce the amount of sound pressure between a sound source and a receiver. Alternate names for this process include lowering the decibel level, soundproofing, or acoustic insulation. Soundproofing materials should absorb or reduce noise by a significant amount (in dB). Different types of soundproofing materials excel in blocking out sounds in different contexts. Soundproofing materials are your best bet when trying to reduce the amount of noise coming from another room or building into your own.

    Indirect sound waves, such as those caused by echoes, resonances, and reverberations, can be reduced with the use of soundproofing. It can also dampen the spread of unwanted indirect sound waves, which would otherwise be audibly obvious to a passive listener.

    Both homes and businesses can benefit from soundproofing. The primary goal at this time will be to minimise or eliminate any outside noise. Existing structures like windows and doors are typically prioritised when soundproofing a home. Therefore, double-paned windows and drapes are the go-to solutions for soundproofing a room. In some cases, soundproofing can be further enhanced by installing exterior windows.

    Restaurants, schools, and workplaces can all benefit from soundproofing to create a more peaceful environment for their employees and customers. Soundproofing technologies are increasingly used in office construction to reduce distractions and boost productivity in open floor plans. Places where private conversations take place could benefit from the installation of such technology.

    Methods of Soundproofing

    Maximum Distance

    Sound travels less from house to house when there's more space between them. Of course, there are times when this is not feasible. 

    Existing Obstacles

    Positioning your new granny flat behind existing structures (such as a garage, shed, tree, or fence) is a second option. This has the extra benefit of being the most economically viable option. 

    New Obstacles

    The third strategy is putting up new barriers, such as fences, plants, and garden structures. 

    The External Facade

    The fourth option is building the granny flat out of bricks or concrete blocks. These days, you may find a wide range of acoustic goods on the market. The price is higher, and this style may only work with some home decor. 


    The sixth strategy is to reduce the number of windows in the main part of the house. Alternatively, you might have your windows double-glazed. The cost of the latter is often substantial. 


    This sixth strategy works wonderfully for creating new granny flats. Acoustically insulated batts are only slightly more expensive than 'regular' ones and provide great sound absorption. Combining multiple strategies is the most effective method of soundproofing. Tenants will have plenty of personal space if you build in walls, plant hedges, use brick for the exterior, and provide at least five metres of space between each unit.

    How Many Distinct Noises Are There?

    Soundproofing materials are effective at reducing three main forms of noise.

    Airborne Noise

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    Simply put, noise that travels through the air is called "airborne noise." Anything from a television to a barking dog may be the source. There is frequently a chain reaction between the generation of airborne sounds and the generation of structural sounds. A barrier or insulation material will need to be installed to reduce airborne noise. The efficiency of such materials as soundproofing will depend directly on their density and thickness.

    Impact Noise

    Strong adhesion between dissimilar materials causes audible impact noises. For instance, if you hammer a nail into the wall, you'll hear a loud impact sound. The noise caused by such collisions can be reduced by installing a barrier between the materials. Floating floors and acoustic ceiling systems are two other viable alternatives.

    Structure-Borne Noise

    A building's structure can be a major conduit for noise transmission. A neighbouring vibrating surface is the cause of this occurrence. The sound of someone walking on a floor in a lower room is a good illustration of this. Noise in the air might originate in the structure below it, and vice versa.

    Flanking Noise

    Flats often suffer from flanking noise because of how sound travels through the walls and floors. Usually caused by impact noise, this type of noise travels throughout a room via the walls. If the walls are built of flimsy material, flanking becomes a major problem. This is why high-density block construction is so widespread in today's apartment buildings. For successful flanking noise minimisation and to ensure compliance with building requirements, blocks with a density of at least 7 kilonewtons should be utilised.

    How to Measure Sound?

    Perceived and actual sound levels may be affected by several things. The effects will vary according to the duration of exposure, the frequencies (or pitches), and the surrounding conditions. Decibels (dB) are the standard unit of measurement for acoustic intensity (sometimes called sound power or pressure). You should know that the physical feeling of hearing is reflected in the logarithmic scale used to measure sound. A sound's perceived loudness and intensity will increase dramatically with even a slight increase in its volume.

    Weighted decibels (dBA) can also be used to quantify sound levels. The results of such a test have a direct bearing on how well your ears can function. It directly affects the force with which sound strikes the ear. Even slight increases in decibel level (dB) can damage your hearing. Exposure to will increase the likelihood of hearing loss due to:

    1. 85 dBA for at least 8 hours
    2. 100 dBA for at least 14 minutes
    3. 110 dBA for at least 2 minutes

    The number of vibrations caused by sound in one second is used as a frequency measurement unit. A person with normal hearing can pick up noises from 20 Hz to 20 kHz. Various electronic devices use the decibel and decibel-and-a-half (dB) scales.


    Soundproofing is very important in a garage granny flat if you want to have a peaceful and relaxing home. To keep noise out and quiet, it's important to insulate the garage's walls, floors, and ceilings. To make a quiet and soundproof room, you need to use the right soundproofing materials and techniques.

    Gas garage granny flats are small, separate homes that are connected to or built into the garage of a main home. People like them because they offer more living room, rental income, higher property values, the ability to live with more than one generation, and low prices. Guests, rental income, a home office or workshop, an in-law suite, short-term rentals, and housing for adult children are all common uses.

    Granny flats come in a number of different styles, such as detached, connected, two-story, and detached studios. A detached granny flat is physically separate from the main house. An attached granny flat, on the other hand, is made to look like it has always been there. When building a granny flat, attached garages can be added without making the overall size smaller. More and more people are realising that having a two-story granny flat in their yard can save them money and time.

    Detached studios are separate buildings that can be used for things other than their main purpose, like when you need more room or work from home. You can build these kinds of granny flats in either a BAL40 or Flame Zone, and they can be a comfortable and affordable option for regular homes.

    Cutting down on the sound pressure between a sound source and a listener is what soundproofing does. It can be used to cut down on or get rid of outside noise, and different types of materials work best in different situations. Soundproofing can help both homes and businesses because it reduces or gets rid of noise from outside.

    Maximum distance, current obstacles, new obstacles, outdoor facades, windows, and insulation are some of the ways that soundproofing can be done. The best way to give tenants a lot of personal room is to use more than one strategy at the same time. Three main types of noise can be cut down with soundproofing materials: airborne noise, contact noise, structure-borne noise, and flanking noise.

    Different things, like the length of exposure, the frequencies, and the situations around the person, can change how loud the sound is perceived and how loud it is. Decibels (dB) are the normal way to measure how loud something is, and weighted decibels (dBA) can be used to measure sound levels. Even small changes in decibel level can hurt hearing, and being exposed to them makes hearing loss more likely.

    With frequency analysis, you can find out how many vibrations sound makes in one second. Normal hearing can pick up sounds between 20 Hz and 20 kHz, and many electronic gadgets use decibel (dB) and decibel-and-a-half (dB) scales.

    Content Summary

    • Garage Granny Flat: Convert your garage into a tranquil granny apartment with soundproofing.
    • Soundproofing is essential for ensuring a peaceful environment in your garage granny flat.
    • Insulating walls, floors, and ceilings in your garage granny flat keeps unwanted noise at bay.
    • The right insulation materials and techniques are pivotal for effective soundproofing.
    • A Garage Apartment or Auxiliary Dwelling Unit (ADU) offers autonomous living space within a primary residence.
    • Increasingly, homeowners are choosing garage granny flats for the additional living space.
    • Garage granny flats can be a source of rental income, providing homeowners with supplementary earnings.
    • Adding an ADU can significantly boost a property's market value.
    • Garage granny flats support multigenerational living, offering privacy and independence.
    • They are an affordable housing solution in pricy real estate markets.
    • Common uses include guest accommodation, offering seclusion yet proximity to the main house.
    • A garage granny flat can be transformed into a dedicated home office or studio.
    • These flats are perfect as in-law suites, allowing elderly family members proximity with independence.
    • Platforms like Airbnb see garage granny flats as popular short-term rentals.
    • For adult children saving up or returning home, these flats provide an independent living solution.
    • Contrary to popular belief, granny flats come in various designs.
    • A Detached Granny Flat offers complete physical separation from the main house, ideal for investment.
    • An Attached Granny Flat seamlessly integrates with the main house, allowing for more or less interaction with neighbours.
    • State regulations allow for the inclusion of a garage in granny flat construction.
    • Two-Story Granny Flats are becoming popular for their financial and practical benefits.
    • Detached Studios serve multiple purposes beyond housing, such as offices or family spaces.
    • Studios are not secondary residences but still form part of the household.
    • Soundproofing reduces sound pressure between the source and receiver.
    • Different materials excel at blocking varying types of sounds in diverse contexts.
    • Soundproofing can dampen indirect sound waves, minimising echoes and reverberations.
    • Double-paned windows and drapes are common tools in domestic soundproofing.
    • In commercial spaces, soundproofing boosts productivity by reducing distractions.
    • Maximum Distance between structures helps in reducing noise transmission.
    • Existing Obstacles like trees or sheds can act as natural barriers for noise.
    • New Obstacles, such as plants and garden structures, can be erected for soundproofing.
    • Brick and concrete blocks serve as effective materials for the external facade of soundproofed structures.
    • Limiting windows or opting for double-glazing can significantly reduce noise intrusion.
    • Acoustically insulated batts are a bit costlier but offer excellent sound absorption.
    • Soundproofing materials combat three main forms of noise: Airborne, Impact, and Structure-Borne.
    • Airborne Noise travels through the air, originating from sources like TVs or dogs.
    • Impact Noise results from the collision of different materials, like hammering a nail.
    • Structure-Borne Noise travels through a building's structure, like footsteps on a floor above.
    • Flanking Noise is a concern in flats due to sound travelling via walls and floors.
    • High-density block construction is popular for reducing flanking noise in apartments.
    • Blocks with a density of at least 7 kilonewtons are recommended for flanking noise reduction.
    • Sound levels, both perceived and actual, are quantified in decibels (dB).
    • Weighted Decibels (dBA) account for the human ear's frequency response.
    • Even slight increases in decibel levels can result in hearing damage.
    • Normal hearing range for humans lies between 20 Hz to 20 kHz.
    • Soundproofing isn't just about peace but also protection from potentially harmful noise levels.
    • Soundproofing is an investment in peace, privacy, and enhanced property value.
    • Combining multiple soundproofing strategies yields the most effective results.
    • Soundproofing is crucial, whether for a family member or a potential renter.
    • From rental income to elderly care, garage granny flats cater to a wide range of needs.
    • Soundproofing ensures that your garage granny flat remains a haven of tranquillity amidst urban chaos.


    FAQs About Granny Flat

    Insulate pipes and plumbing fixtures with soundproof materials. Choose energy-efficient and low-noise appliances to minimize unwanted sound.


    Yes, acoustic panels strategically placed on walls can absorb and reduce sound reflections, enhancing the overall acoustic quality of the space.


    Soundproofing can be done on a budget. Focus on sealing gaps, using weatherstripping, and choosing cost-effective insulation materials. It may require more effort, but it's possible.


    Address footstep noise by adding rugs, carpets, or soft flooring materials. Ensure the installation of acoustic underlayment to reduce impact sound.


    If you want a comprehensive and flawless soundproofing solution, it's advisable to consult a professional. They can assess your specific needs and recommend the best techniques and materials for your garage granny flat.

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