We recently moved into a second hand, semi-detached house. We are newly married and work quite long hours. In the evenings, when we arrive home we can hear our neighbour’s television and, in some cases, their conversations. This is becoming a nuisance to us, particularly as our sleep is being interrupted late at night, with commentary on UFC bouts, loud voices and generally by things going bump in the night. Is there anything we can do to improve this situation?
Current building regulations from the Department of Housing set down certain standards to be met in terms of the transfer of sound from one property to another. Part E of the regulations deals with sound, and states that each wall and floor separating a dwelling from other dwellings or common area shall be designed and constructed in such a way as to provide reasonable resistance to sound.
Transfer of sound from one area to another can be complex. A sound can be carried through air or through a solid element of the house construction by reverberation. Sound travels in waves and can travel through materials. Our childhood fascination with sound travelling from one plastic cup to another through a length of string was a vibrant demonstration of this phenomenon.
Indirect transfer of sound is referred to as “flanking” sound. In general, flanking transmission is the greatest cause of nuisance in modern construction.
A solid element may vibrate when exposed to sound waves in the air. When sound waves strike a wall, this can lead to vibration in the elements forming the wall, which can in turn, transfer this sound energy on to the opposing side of the wall (into your neighbour’s property).
In my experience, the problem can be exaggerated where dry-lining or dabbed plasterboard finishes are used on the party wall. A thin layer of plasterboard placed against the party wall can reverberate leading to exaggerated sound transmission between properties.
Manufacturers of plasterboard linings set down clear criteria to be followed in terms of fixing plasterboard on party walls, where the manufacturer states that all edges of the plasterboard are to be sealed/adhered to the wall in order to prevent/reduce air movement and reverberation. Regrettably, it is not untypical that there would be poor attention to detail in fixing the plasterboard to the party wall, resulting in exaggerated sound transmission.
Sound transmission
Sound can also travel in voids or gaps in building materials. Air pockets or poorly jointed materials will allow sound transmission through. Sound can also travel through attic spaces, through electrical sockets, if these are placed back to back on party walls, and indeed sound can sometimes travel through cavities or roofs to bay windows, shared lean-to roofs and the like. I recently had a case where a neighbour experienced sound travelling down the chimney from a roof light in my clients converted attic. The correction or improvement of soundproofing cannot therefore be guaranteed by a single action.
With all matters such as this, I generally recommend that the simple things are carried out first. Gaps around windows should be sealed if you have recognised that sound travels or can be heard from a particular area. If so, then any gaps or voids in this area should be sealed with plaster fillers, foam or mastic sealant.
If it is discovered that the sound transmission is the result of reverberation due to incorrectly adhered plasterboard linings on the party wall, regrettably there is no easy solution here. The plasterboard linings would need to be replaced and adequately secured into position. In the event that this is the route chosen, I would recommend that consideration is given to introducing a soundproofing quilt. Best results would be achieved by providing a new independent stud wall with soundproofing quilt insulation contained within this new, stud framework.
Soundproofing plasterboard can then be fixed to the new lining, giving full separation from the party wall. This will improve impact and flanking sound transmission. Obviously, there would be some loss of space within the rooms and you may decide to carry out this improvement work to your bedroom only. An inspection by a building surveyor may help to identify the first steps in your getting a good night’s sleep.
Building regulations do require that a sample of houses in new developments be tested for sound transmission. Hopefully, errors of the past will not be repeated.
Noel Larkin, Chartered Building Surveyor and member of the Society of Chartered Surveyors Ireland, scsi.ie
