We continue from last article where we explained the serious problem of noise in Spain in almost on all ambits of life. This week we propose to concentrate on the practical side of noise insulation.
We continue from last week article where we explained the serious problem of noise in Spain in almost on all ambits of life. This week we propose to
concentrate on the practical side of noise insulation.
Locate the noise.
Prior to soundproofing a home or a space, the first step is to find out where the noise is coming from. To do this, it is necessary to understand that some noises cannot be removed altogether; at the most sound insulation could absorb some of the energy produced by the source of the noise.
We also must differentiate between soundproofing i.e. to carry out the necessary works in an enclosure to minimize the sounds getting in from outside, or to do an acoustic adaptation i.e. to prepare a space so that the sound generated within that space it is not transmitted outside.
Different types of sound. Different solutions.
There is to my mind another variation to have in mind and that is the airborne sound, sound from loudspeakers and the vibration sound produced by impact, for example someone doing flamenco dancing on the floor above. The solutions for each of the above are totally different.
If you want to soundproof a room properly I am afraid that some building work is required since it is essential to place a barrier between the sound source and the room itself.
It must be borne in mind that there are a great variety of noises. Some come from the roof of the building; from a lift shaft, air-conditioning machines, fumes extractors etc.
Inside the home the most frequent noise come from toilets, televisions and music devices and individual air conditioning machines. And from outside the home: traffic, fire ambulance, train or aircraft are a constant sample of the noise that we bear.
Different frequencies. Different thickness.
Currently there are many materials that serve as noise insulation; many of them have thermal insulation characteristics. Anyway, the best material to isolate airborne sound is that that has the biggest amount of mass (weight) is the best material that we could use, for example lead, but obviously this material is too expensive to be used on large areas: So, it seems obvious that a layer of mortar, or brick of various centimetre thick insulates better than other materials like glass.
However sound is made up of various frequencies so it is advisable to use an agglomeration of different materials that combine mass and elasticity for best performance. For instance plaster and mineral wool.
However if you want to stop noise from getting out of a room then it is recommended to use soft and uneven surfaces such as cork, wood agglomerated or mineral fibres as expanded polystyrene, cellular glass wool or, polyurethane. Here again we are dealing with airborne sounds.
Noise behaves like a liquid.
Another fact to have in mind is that noise behaves like a liquid, so if a surface is sound insulated but you leave a hole or a part without insulation the solution and the expense of the sound insulation is wasted. You will not benefit from insulating a part only, the whole surface exposed to noise needs to be treated.
Let me also state that often windows are the weakest link on the façade specially the space between the roller shutter box and the external space. People spend great deal of money installing expensive double glazing systems to find out that they have the same noise problem, just because they have overlooked the finishing edges of the window frame and the wall or the space around the shutter box.
Special attention to junctions and joints.
Having said that and by paying attention to the detailing of junction between the windows and the surrounding wall an efficient method to fight outside noise is the placement of soundproofed windows. Double glazing windows or double glazing can be a good remedy to noise trouble.
Insulation is improved if both glass panes are of different thickness; this is because each pane will absorb different sounds frequencies. This is an important point to remember.
If the window is made of wood and does not fit perfectly, strips of rubber can be fixed on the frame edges so that window and frame are airtight and prevents the passage of air, the vehicle for noise.
If you want a temporary solution, or the budget is very tight, you could resort to more homemade solutions. The use of blinds and thick velvet curtains or other heavy fabrics can help absorb a bit of sound. This works for sound made inside that we want not to go out as for outside noise that we are preventing from getting in.
When there is an empty cavity wall you may increase the sound insulation of that wall by introducing an appropriate insulation. You can also create a double wall by installing plasterboard and filling the cavity with insulating materials.
Next week we will deal with impact sounds and techniques to improve sound insulation for impact and vibratory noise from machinery.