Acoustic Insulation and UK Building Regulations

by Mark Row

Relevant Regulation Regarding Soundproofing

As most of you probably know by now, acoustic insulation is no longer an option but also an obligation, since certain levels of soundproofing must be achieved within residential buildings in order to meet the conditions prescribed by applicable regulations. However, this should not be seen only as an obligation, since proper insulation can drastically improve the quality of life and protect us from undesirable sound levels, defined as noise which can ultimately endanger our health and overall performance. This is why it is good to know some basic rules that this set of compulsory regulations provide. This guide on acoustic insulation and UK building regulations offers just that.

Approved Document E under Building Regulations

Probably the most important document concerning soundproofing in residential buildings is Building Regulations Approved Document E which is applicable in the territory of England and Wales. It basically provides practical guidance for fulfilling conditions prescribed by Building Regulations, Regulation 7 and Schedule 1. Approved Document E (AD E) prescribes acoustic insulation levels alongside suggested separating constructions forms. Note that these separating constructions are only recommended but do not guarantee that the prescribed levels of sound insulation will be met in practice which means that the developer will have to demonstrate that the constructed residential building meets the prescribed sound levels set by means of Pre-Completion Testing*. Practically, every construction needs to be tested on site in order of determining whether it meets the set requirements.

­* Pre-Completion Testing is carried out by a specified test body, on new houses and flats but also any conversion or change of use into flats. The test body delivers the copy of the test results to the local building control office which need to approve it in order of issuing a completion certification and signing off the job. If the requirements set by the Building Regulations are not met remedial works need to be carried out and re-tested. Note that if the test results are not in compliance with the prescribed regulation, the property will not be signed off as completed.

The following table sets basic sound insulation values in residential buildings.

                                 *except walls with doors

Additionally, building parts that contain residential rooms and flats should have an area that is equivalent or greater that the floor area covered with at least Class C absorber. When it comes to stairwell in buildings that contain residential rooms and flats, the area corresponding to the area of the stairs and the top floor ceiling area should be covered alternatively with Class D absorber or at least 50% of the area should be covered with Class C absorber (or better).

 Robust Details

Since the Pre-Completed Testing is somewhat complicated and time consuming the previously mentioned AP E has been amended in order of allowing Robust Details as an alternative. Namely, Robust Details series have been developed by the Home Builders Federation and administered by Robust Detail Ltd,  in order of avoiding Pre-Completion Testing for new flats and houses, by basically setting construction forms that have been pre-tested in order of meeting the requirements and standards of sound insulation prescribed by relevant regulation. For more detailed information, please visit robustdetails.com.

Technical Handbook Section 5 – Building Standards

Instead of the mentioned AD E applicable in England and Wales, transmission of sound resistance is covered by the Technical Handbook Section 5, applied in the territory of Scotland. Namely, there are a few important differences in the AD E and Section 5 regime. First of all, site performance is measured solely by the DnTw value, unlike the AD E which also introduces the Ctr correction factor (for low frequencies).

Robust Details incorporated in the Robust Detail Handbook are applicable in the territory of England and Wales. However, some of the set constructions could be suitable and correspond to the Section 5, upon testing. Other than that, there is no an alternative scheme that could replace the on-site testing.

Finally, there are some differences in required values in sound insulation, including the one in internal partitions and mid-floors, where the minimum value prescribed by the Section 5 is Rw=43dB. Also, unlike AD E, Section 5 sets no rules and requirements for building common areas sound absorption. For more information go to Scotland Building Standards.

If you need more information about Soundproofing and UK Building Regulations feel free to post your questions in the comments section below.