For most a garden is an oasis and most likely a homeowner’s favourite spot to spend extended periods of time to relax and unwind – especially during the warmer seasons.
Whether a small courtyard, or a more expansive green plot with mature shrubs, plants and flora, it’s a place where we want to spend as much time as possible whilst the weather is at its finest.
For some homeowners however, this is not always the case.
Many homes are unfortunately built close to busy roads and highways that emit the constant buzzing of traffic noise.
In most cases, the noise created can be overheard from nearby gardens, which spoils the ambience and ability to enjoy the space.
In short, noise pollution from nearby roads and traffic is a massive nuisance.
Apart from being off-putting to use your garden, you may also end up suffering healthwise in the long term.
So, if you’re one of the many people suffering from traffic noise or general nuisance noise in your garden, read on to discover a number of methods to soundproof your garden and dramatically reduce unwanted noise pollution.
Acoustic Principles/Treatment Methods
There are two or three acoustic principles or approaches you can choose from when tackling external sound mitigation – deflection, absorption and in effect both by energy conversion.
When dealing with external noise transfer, no two scenarios will be the same and it’s important to understand the basics of what you are trying to deal with, from where it’s starting and how it’s travelling to you in your particular location.
Traffic, by nature of what it is, is moving and varying in way of dB levels, speed, frequencies, power and pressure.
The sound waves propagate away through the air in all directions and will act differently with weather, atmospheric pressures and when bouncing from other objects.
This means that whatever barrier or principle you adopt invariably needs to be a little longer or wider or higher than just the area you think is causing the problem, such as a hole in a single fence panel or a gap in the bushes or tree line.
An initial and very basic approach would be to at least block line of sight (a straight line in which an observer has unobstructed vision of the noise problem) and then add a little bit more.
If you can see it, you are invariably going to be hearing it.
And remember, whatever barrier you adopt has to be not only effective acoustically but also fit for purpose, affordable, stand the test of time and be aesthetically pleasing.
Something which is often forgotten when desperately trying to get rid of an unwanted and seemingly never ending drone.
Let’s look at the differing approaches.
As the name suggests, this technique aims to deflect or reflect unwanted sounds in the opposite direction.
An example of this application in the garden is to install a high perimeter wall or fence around the garden, so that the traffic noise is effectively bounced back from where it came.
This technique will work better than attenuation but understandably, is a more expensive option than planting shrubs and hedgerows.
Consideration should be given to structures and objects on the opposite side of the road.
This may sound irrelevant however, sound waves travel in all directions and could therefore effectively travel away initially, only to be deflected from the other side of the thoroughfare and bounce straight back toward your barrier.
Worse still, they could be deflected straight over the top of the barrier depending on how tall it is. More on this later…
Sound absorption refers to the process by which a material, structure, or object takes in sound energy, absorbing to reduce the sound power and sound pressure, thus reducing sound propagation.
One way to achieve this sound muffling effect, is to plant thick shrubs strategically around the perimeter of the garden so that they can absorb sound waves from the road.
This method at best may muffle unwanted sounds in the garden, although seldom has the desired effect as invariably it is not dense and thick enough to deal with problematic frequencies to remove completely.
Absorptive, open cell materials/media used as an external barrier have a limited effect and unless protected simply wick moisture, which reduces the ability to further absorb.
Acoustic Energy Conversion
Acoustiblok Isolation Membrane is a material which works by converting sound energy into trace heat energy.
When sound waves come into contact with the membrane, it vibrates the molecules of the materials which in turn creates friction which is cleverly converted to a trace heat energy.
Thus the material works by converting a more problematic acoustic energy into a less problematic heat energy, which is simply transferred through the material sideways to reduce flanking transmissions.
The material is highly effective as it does not have the associated issues and required thicknesses of absorbing materials, nor the rigidity or mass of dense materials.
Be it a wall, fence, or foliage, we’re now familiar with the simple process of how noise barriers work.
However, the type you choose will depend on a number of key factors including preferred type of construction, location, desired effect, height and length and budget.
Barrier Height & Length
Put simply, the higher the barrier, the more effective it will be at blocking or deflecting noise.
To close the line of sight is a good starting point, but the higher the proposed barrier is the better.
This is referred to as the ‘angle of incidence’ with an increased height or length offering an increased angle from the point of original source ignition of the noise to the top of the barrier to force change of effect to acoustic waves.
For example, a fence that is at least two metres tall is far less likely to allow sound to pass over it than a barrier at one metre high or lower.
As you might imagine, as a rule of thumb the denser the barrier, the more likely it will prevent that noise from passing through it.
This is not completely true as a material’s own density comes with rigidity which in turn can provide a flanking route.
However, this does not tend to be such an issue externally compared to the problem of sound waves going up and over or around the proposed structure.
So if you live close to a particularly busy street that produces considerable levels of noise, you may need to invest in a thicker, denser solution combined with the appropriate or sufficient dimensions – height/length.
Sound has the ability to find ways to pass through even the smallest of gaps or cracks.
So any barrier you build you must ensure that there are no gaps or obvious places where sound can pass-through whatsoever.
Even the tiniest of holes or gaps could considerably reduce the effectiveness of the barrier.
Barrier placement plays a crucial part in its efficacy when reducing unwanted traffic noise.
The closer the barrier is to the source of the noise, the more effective it should be at sound reduction by increasing the angles of incidence from the point of original source ignition to the top of the barrier.
Regardless, the most obvious positioning would invariably be at the perimeter boundary which may already have some type of existing structure in place.
Depending on the lay of the land and elevations, secondary barriers may be considered.
Perimeter Barrier Options
Garden fences come in various types, designs and styles.
You may wish to consider the most suitable soundproofing material and option that will be most effective at reducing unwanted noise.
Brick walls are robust and durable providing increased levels of density and mass which we all know is a basic principle to mitigating sound.
If installed to a good height, they are effective at blocking unwanted noises, especially if built to a reasonable thickness.
This may however not be the preferred option for many people as it is invariably a very costly option when considering material costs, structural foundation and skilled labour to erect.
Local council planning permission may also be required for any reasonably effective height wall from the local authority.
Aside from the above, many people do not like the thought of having a giant brick wall surrounding their garden, as it creates a displeasing and enclosed feel to the space.
Timber fencing is one of the most common choices homeowners make when installing a garden perimeter sound barrier.
Apart from being fairly easy to install, they are also reasonably cost efficient.
However, standard timber fences do have a number of common pitfalls.
Wooden fences such as shiplap or feather edge slats can be erected to close the line of sight and be aesthetically pleasing, however they have a tendency to allow sound to pass through gaps in each of the slats.
This can become worse over time with weathering and shrink back of the timber slats.
Overall, timber is not considered a particularly effective sound dampening material.
So if your nearby road noise is particularly bad, a fence in isolation may not be enough to tackle the problem.
Some of the more common metal fences may be used more as security fencing and not be preferred as they are not particularly aesthetically pleasing.
In a lot of cases, the fully closed varieties are also quite ineffective at reducing unwanted road noise and add to a high level of resonance and regeneration.
Any open varieties such as wire or chain link quite obviously let acoustic energy pass straight through them.
Although they can offer a cost effective sound structure to create a perimeter barrier onto which acoustic barrier membranes can be applied.
Products like Acoustifence are ideal for this scenario and the results are very impressive to say the least!
Shrubs & Hedging
Shrubs and hedges are often preferred as they complement the garden nicely, offer an aesthetically pleasing site line and also reduce air pollution.
However any type of planting needs to be rather thick, dense and very mature to have any real effect as problematic frequencies will pass through foliage as if it is not even there.
They also come with the need for maintenance, needing regular pruning.
Some types of mature shrubs come at a hefty price.
So if you need to block unwanted noise in a hurry, you can’t buy younger plants and be made to wait several years for them to grow to the desired height and thickness.
Even then the likelihood of success is rather slim.
Acoustic fences are becoming increasingly popular as they are very effective at blocking unwanted noise.
Invariably built with much thicker, denser, tongue and groove interlocking timbers to increase acoustic values.
A sensible approach is starting from scratch and a new structure needs to be erected.
Although they may come with a slightly higher price tag, they are still far cheaper and more aesthetically pleasing than a gigantic brick wall.
They are also far more effective at blocking unwanted sound too.
In the majority cases, most gardens will already have a fence installed.
So the natural choice for any homeowner is to try to improve on what’s already installed on the basis the existing is structurally sound, sturdy and strong enough.
Acoustiblok AcoustiFence membrane is perfect for this scenario as it can be installed onto the existing fence and acts as a highly effective noise barrier by converting sound into energy.
The material is easily hung by attaching to the existing substrate or support posts by additional timber support or using the grommets/eyelets.
So installation is quick and hassle free saving on labour costs.
Products like Acoustifence are ideal for this scenario and the results are very impressive to say the least!
Other options favoured by many garden owners include:
Rather than focusing on reducing the traffic noise, you might consider ways of obscuring it or deflecting your attention away from it by altering the ambient values by adding other more pleasant noises.
With the sound from a fountain or water feature, you’ll be distracting yourself away from the undesirable sounds from the street, and instead focussing on the calming sounds of running water.
This changes the perceived levels of the nuisance noise.
By placing a number of wind chimes in and around your garden, you can help to create a more tolerable atmosphere that distracts from the road noise.
Even with a gentle breeze, wind chimes start to jingle and produce pleasing sounds that help you forget or at least ignore the traffic noise from the nearby roads.
The more trees you plant, the greener your space.
And the more you plant, the chances are you are increasing the sound attenuating properties of your garden.
That said, larger trees with larger limbs and branches can actually deflect the sound back towards the ground.
Deflection or reflection in this way is known as urban resonance.
Certain trees are more effective at reducing traffic noise more effectively.
Understandably, evergreen trees rather than deciduous varieties tend to be better due to their density and all year round foliage.
Examples include Leyland Cypress, Eastern White Pine, and Arborvitae.
These can become very large trees that grow quite quickly and as they grow they tend to create height whilst losing the lower growth and density which of course can then leave gapping at the bottom near the ground.
Reducing unwanted noise from nearby roads can be quite difficult especially once one tunes in to the particular noise/frequencies and the perceived levels are increased.
Ultimately, the level of the noise produced will determine the most suitable noise reducing application.
Budgets, aesthetics and convenience all play a part, so there’s rarely a single solution to suit all scenarios.
In some instances, small changes such as plants and garden accessories may suffice.
But in others, more robust solutions may be in order which require contractors to install more permanent structures such as high fences and walls, or even better, specialist acoustic noise reducing membranes to drastically reduce the sound of nearby traffic.
If you are unsure of which option is best suited to your needs, you can always speak to a professional acoustic consultant who can offer up the best ways to tackle your unwanted noise, and get back to enjoying the tranquility of a quiet and peaceful garden once again.[external_footer]