{"id":526,"date":"2021-08-26T15:33:42","date_gmt":"2021-08-26T15:33:42","guid":{"rendered":"https:\/\/thermal-economics.co.uk\/acoustic\/?p=526"},"modified":"2023-09-14T08:43:54","modified_gmt":"2023-09-14T08:43:54","slug":"quick-guide-to-sound-insulation-for-floors","status":"publish","type":"post","link":"https:\/\/thermal-economics.co.uk\/acoustic\/2021\/08\/26\/quick-guide-to-sound-insulation-for-floors\/","title":{"rendered":"Quick guide to sound insulation for floors"},"content":{"rendered":"
[vc_row][vc_column][vc_column_text]Many flats aren\u2019t new buildings; they used to be large houses, offices, even factories.\u00a0 However, they all need to comply with the Building Regulations.<\/p>\n

This sometimes means extra improvements are needed to make sure the building is suitable for modern residential use.<\/p>\n

Thermal Economics is well known in the construction industry for our IsoRubber range of sound insulation for floors.\u00a0 In writing this guide, we hope that you will be better informed of the sound performance requirements in the Building Regulations, and that you\u2019ll find it easier to select the best sound insulation product for you.<\/p>\n

Building Regulations and sound performance<\/h2>\n

The Building Regulations are complicated by the sheer volume of documents and amendments; there is no one publication which explains everything, and there is not even one legislative document which covers all of the requirements.\u00a0 So, if there are no \u2018Building Regulations\u2019, then what are the Building Regulations?<\/p>\n

The Building Regulations have a very real power, which is derived from The Building Act 1984; which allows the Government to make and enforce regulations with respect to the design and construction of buildings by statutory instruments, and also to publish \u2018approved documents\u2019 which give practical guidance on achieving the requirements.<\/p>\n

Despite the frequent amendments to the Building Regulations, the sound performance requirements are largely unchanged since 2010; so the only statutory instrument that needs our attention is:\u00a0SI 2010\/2214 The Building Regulations 2010<\/a><\/p>\n

Building flats \u2013 Building Regulations<\/h2>\n

Paragraph E1 of Schedule 1 requires that flats should be designed and constructed in such a way to provide \u201creasonable resistance to sound\u201d from other parts of the same building and from neighbouring buildings.\u00a0 Or, in other words, the separating building elements between flats must have sound insulation!<\/p>\n

Regulation 41 in Part 9 also gives a requirement for sound testing to demonstrate the effectiveness of the sound insulation.\u00a0 But this still doesn\u2019t explain how much insulation is required or even what the criteria for sound insulation testing are.<\/p>\n

Approved Document E<\/h2>\n

Officially, as an approved document,\u00a0Approved Document E<\/a>\u00a0is guidance only.\u00a0 However, it is a primary reference document for Building Control Officers and\u00a0de facto<\/em>\u00a0minimum standards.<\/p>\n

Moreover, Approved Document E provides some specific requirements for proving compliance with the Building Regulations; which for material change of use in flats is:<\/p>\n\n\n\n\n\n
<\/th>\nAirborne sound insulation<\/strong>
\nD<\/em><\/strong>nT,w<\/sub><\/strong>\u00a0+\u00a0C<\/em>tr<\/sub><\/strong>
\n(dB)<\/strong><\/th>\n		Impact sound insulation<\/strong>
\nL<\/em><\/strong>\u2019nT,w<\/sub><\/strong>
\n(dB)<\/strong><\/th>\n<\/tr>\n
Walls<\/td>\n\u2265 43<\/td>\n\u2014<\/td>\n<\/tr>\n
Floors & Stairs<\/td>\n\u2265 43<\/td>\n\u2264 64<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

 <\/p>\n

Material change of use includes where a house is being converted into flats or a care home with individual dwellings within the same building.<\/p>\n

Noise transmission is divided into two separate categories: airborne and impact; although impact noise transmission is only applicable to floors and stairs.<\/p>\n

Airborne noise can be described as the passage of sound through the air and materials by sound waves; such as radios, televisions, people talking, &c.\u00a0 However, impact noise sources are always footfall on floor surfaces or similar.<\/p>\n

Sound Insulation in flats \u2013 Decibels and Sound Pressure Levels<\/h2>\n

The units for sound transmission are decibels (dB), which are a measure of how loud a noise is.\u00a0 Although the loudness of how we perceive noise also depends on pitch as well as it\u2019s volume.<\/p>\n

We perceive LOWER frequencies to be louder than HIGHER frequencies, even when both sounds have the same amplitude.<\/p>\n

A sound pressure level is a measured level of noise in the room measured.\u00a0 Sound is measured at intervals of one-third octaves to measure a range of frequencies, and averaged across a weighted standardised curve to compensate for the perceived difference in loudness between frequencies.<\/p>\n

This is shown by the subscript: \u201cnT,w\u201d.<\/p>\n

Measuring Airborne Sound<\/h2>\n

Airborne noise is measured by adding a noise source with known frequencies and amplitudes to a room (usually via a spherical or hemi-spherical speaker), and measuring the difference between the weighted standardised sound pressure levels in the adjoining flat with and without the noise source.<\/p>\n

The sum of the difference between sound pressure levels and a spectral adaption term must be at least 43 dB for the floor to comply with Approved\u00a0Document E.<\/p>\n

Measuring Impact Sound<\/h2>\n

Impact noise is measured by adding a noise source with a known frequency via a tapping machine to simulate footfall, then the weighted standardised sound pressure level is measured in the room below.<\/p>\n

The difference is not important, but it is important that the noise does not exceed a maximum threshold.\u00a0 Therefore, the floor satisfied Approved Document E if the tapping machine does not raise the sound pressure level above 64 dB.<\/p>\n

Insulating floors in flats<\/h2>\n

In short, a separating floor should absorb airborne noise transmission and isolate against impact noise with a resilient layer.\u00a0 A good construction detail will also design out sound paths that bypass the sound insulation; leading to unwanted, flanking sound transmission.<\/p>\n

However, the first thing that must be established is whether the floor construction is timber (also includes I-beams, web joists and other steel joists); or concrete (including in-situ cast, pre-cast concrete planks and composite profiled decks).<\/p>\n

Timber floors in flats<\/h2>\n

Thermal Economics standard refurbishment solution for joisted floors is now the\u00a0IsoSonic\u00a0Dekfloor<\/a>\u00a0system.<\/p>\n

Where possible, lath-and-plaster ceilings should be retained subject to achieving the correct fire resistance; otherwise replaced with two layers of gypsum plasterboard on either our IsoSonic Ceiling Hangers \/ Brackets or resilient bars to reduce flanking sound transmission.\u00a0 Key requirements for the ceiling are:<\/p>\n