Building acoustics is an important consideration for projects as it can affect productivity, wellbeing and communication. There are many factors which can influence building acoustics, including shape and volume of space; characteristics of surfaces and materials within, enclosing or separating the space in terms of sound absorption, transmission and reflection; generation of sound; airborne sound transmission and impact noise.
The reverberation time of a room or space is defined as the time it takes for sound to decay by 60dB and affects how space sounds. It is linked to the volume of the room and the amount of sound absorption treatments incorporated - rooms designed for speech typically have a lower reverberation time than those designed for music which might have a higher reverberation time to add richness and warmth. Sound absorption refers to the loss of sound energy when sound waves hit ceilings, walls and floors, and they are absorbed.
Sound insulation is a technique that is used to restrict sound from travelling between separate spaces through walls, ceilings and floors. Sound transmission is the passage of sound into a room from a source located in another room or outside the building.
The passage of sound into one room of a building from a source located in another room or outside the building is termed ''sound transmission". Transmission loss or Sound Reduction Index, R dB, is a measure of the effectiveness of a barrier (e.g wall, floor, door etc.) in restricting the passage of sound.
Part E of the Building Regulations sets minimum standards for design and construction in relation to the resistance to the passage of sound.
The following guide reflects the prices a client might expect to pay on a medium-sized project for some products or measures which may be specified in relation to acoustics:
|Prices allow for installation but do not include the contractor’s preliminaries, overheads and profit margin.
|Stud partition; Rw 56dB, FR 30mins; 2700 – 3000mm high
|£200 - £230/m
|Stud partition; Rw 63dB, FR 30mins; 2700 – 3000mm high
|£230 - £260/m
|Timber flush single doors with solid high-density chipboard core; Rw 30dB, FR 30mins
|£800 - £850
|Timber flush single doors with solid high-density chipboard core; Rw 30dB, FR 60mins
|£830 - £890
|Class A suspended ceiling with visible grid and demountable tiles
|£60 - £75/m2
|Class A monolithic ceiling system comprising of a stone wool panel (40mm), filler and acoustic
|£70 – 90/m2
|Class C perforated plank suspended ceiling
|£65 - £80/m2
|Specialist, spay applied noise reduction insulation; 50mm metal stud; 12.5mm plasterboard; 35mm acoustic render
|£100 - £130/m2
|Plant room acoustic wall lining panels
|£75 – 100/m2
|Suspended acoustic ceiling panel; circle 800mm diameter
|£280 - £300/Nr
|Suspended acoustic ceiling panel; rectangle 2400 x 1200mm
|£450 - £480/Nr
|Acoustic cradle flooring system
|£60 – 80/m2
|High load bearing screed isolation / underlay 10mm thick; impact rating 30dB, airborne rating 62dB
|£26.50 – £32.50/m2
|High load bearing screed isolation / underlay 15mm thick; impact rating 30dB, airborne rating 62dB
|£31.50 – £45/m
This piece first appeared in RIBA Journal September printed edition.