How to Sound-Proof a Garden Room Cinema or Music Studio

What is sound and how can it affect you?

All sounds are waves of pressure that move through the air. They are measured in decibels (dB). Each increase of 10-dB represents a tenfold increase in intensity and a doubling of loudness. The human body reacts to the physical force of sound through both hearing and feeling. If a sudden, powerful sound reaches the ear, it is transmitted to the brain and the body will react to it by triggering the nervous system. That system evolved to provide protection from danger and triggers a flight or fight response. For this reason, hearing loud noises can be both annoying and unsettling.

Should you sound-proof your garden room?

You can sound-proof a garden room either to keep external noises out or to prevent the noise you might make from escaping. Sound-proofing is a significant additional expense and so it is worth thinking about whether you really need it.

An insulated garden room with double glazing will usually be sufficient to limit the impact of external noise to an acceptable level. You could reduce that impact further by erecting fences and planting hedges around the perimeter of your garden as these will deflect or absorb external noises. It is also worth choosing roofing materials with soundproofing properties.

For a music room or home cinema, soundproofing is essential to prevent your leisure pursuits from causing issues for your neighbours. A properly soundproofed building will also deliver better acoustics and so will enhance your enjoyment of your space.

Begin with an insulated garden room

It is important that you begin with an insulated building. Many garden rooms are well-insulated but if your structure boasts only a timber frame and external cladding, you will need to insulate your garden room before proceeding with soundproofing.

Firstly, insulate the hollow frames of the walls and roof using either thermal insulation or acoustic mineral wool that provides superior acoustic insultation. Then, use dense material to clad the inside of your room as this will increase mass. Your cladding choices include two layers of acoustic grade plasterboard, Oriented Strand Board (OSB) or cement particle board. The latter will deliver the greatest increase in mass and so provide the best soundproofing.

Create a room within your garden room

It is important to remember that noise creates both sound waves and vibration energy. Sound waves will project 360 degrees around the room. They must be blocked in all directions and vibrations must be absorbed. If vibrations reach the structure of the building, they will easily spread. If your walls are soundproofed but your floor isn’t, vibration will pass through the floor and reach the walls.

Vibration can pass from a non-soundproofed element of the room into a soundproofed element. This is called “flanking”.

You will benefit from the best results in terms of containing sound and vibration if you create a room within a room. In other words, you will need walls in front of your outer walls that are not connected to them, together with both a suspended ceiling and a floating floor. This will contain sound energy, preventing it from reaching the external structure of your building but will also reduce the internal space of your building.

A room within a room can be created by:

1. Building independent stud frames in front of each wall but not touching them. The gap between the inner and outer walls should be at least 10mm and the bigger the gap, the better your results will be. Ideally, place the stud frame on an isolation strip around the perimeter of the room.
2. Filling the hollow cavity you have created with acoustic insulation. This will prevent sound from resonating in that cavity. Acoustic mineral wool would be the perfect insulation material.
3. Using acoustic isolation clips to decouple the existing structure from new internal walls. Isolation clips provide secure connection points while reducing the transfer of sounds between the internal and external walls.
4. Cover new internal wall frames with multiple layers of heavy, dense materials. Mix different types of material so that a wider range of sound frequencies are blocked. Acoustic grade plasterboard and FlexiSound 5 are excellent choices.
5. Soundproofing the floor and ceiling. The way you do this will depend on the room height you have to play with. The better the soundproofing, the more space you will take up and the more costly the project will be.

1. Minimal loss of space – fix your suspended ceiling directly to the bottom of the existing ceiling joists and insulate between joists with acoustic mineral wool. Cover with acoustic grade plasterboard or if space permits multiple payers of suitably dense material. Complete with acoustic panels or tiles. These can enhance the look of your space while improving sound quality. Place vibration absorbent matting between the building’s structural floor and the wood or laminate flooring.
2. Optimised soundproofing – keep the existing ceiling in place but installing secondary ceiling joists. Fill the secondary joists with acoustic mineral wool insulation, then install the suspended soundproof ceiling to the secondary joists using isolation clips and complete the ceiling with acoustic tiles or panels. For the floor, float timber batons on isolation strips. Fill between the batons with acoustic mineral wool insulation. Install isolation strips on top of the batons, then add a structural floor layer. Add soundproofing matting on top before laying your wood or laminate flooring.

What about windows and doors?

Windows and doors can be the weak points of your soundproofing system. You will achieve the best results if your building doesn’t have windows. But most garden rooms will have windows which should be double glazed. If you have created a room within your room, install windows on the internal frame and use acoustic glass. The internal stud frame will also enable you to fit a second door. Both the external and internal doors should be solid core fire doors and boast acoustic seals.

If you don’t wish to construct a room within your room, hang acoustic curtains in front of doors and windows. These dense curtains block external noise while also improving acoustics in the room.

Can your choice of furnishings help?

Cushions, upholstered furnishings and shelves filled with books will help to absorb sound, minimising the level of noise that can escape from the room.

How do you address ventilation?

A properly soundproofed space will be air-tight and so the room will lack natural air flow. You will need ventilation, but this will always prove to be a weakness in your soundproofing system. Depending on your budget, you could choose to install a digital air conditioning system, a powered ventilation system or a simple in/out duct. Any ducting must be insulated and feature baffles to minimise the transmission of sound.

Final Thoughts

Properly soundproofing your garden room will be costly and you may need to use the services of expert soundproofing professionals to complete the project. It is best to consider whether you require a soundproofed space before investing in your garden room as a bespoke building could be designed to incorporate the soundproofing you need and to have fewer windows. It is easier to soundproof a garden room during construction than to fit the required features retrospectively.

If you are looking for the perfect music studio or home cinema, soundproofing will make all the difference to your enjoyment of the space and will ensure that your hobby or work won’t have a negative impact on your neighbours. Soundproofing could also add value to your room and therefore to your property which would become incredibly attractive to music enthusiasts should you wish to sell it.