Dense and lightweight aggregate concrete blocks can be used for constructions meeting the requirements of Part E of the Building Regulations (England & Wales)

Approved Document E to the Building Regulations (England & Wales) 2010 Resistance to the passage of sound – 2003 edition incorporating 2004, 2010, 2013 and 2015 amendments, requires dwellings to be designed and constructed so as to provide reasonable resistance to sound from other parts of the building and from adjoining buildings.

The approved document introduces minimum performance levels for separating walls, certain partitions and separating floors.

The minimum requirements for airborne sound insulation of separating walls and relevant partitions are:

Separating walls between new dwellings
45_DnT.w + C_tr  dB (site tested value)
Walls between rooms in residential buildings
43_DnT.w + C_tr  dB (site tested value)

Relevant partitions (between bedrooms or a room containing a wc and other rooms)

40 R_w  dB (laboratory tested value)

Two methods of demonstrating compliance with the requirements for site tested values are:

• Pre-completion testing in accordance the regime identified in annex B of Approved Document E
• Building the separating wall and flanking wall in accordance with one of the Robust Details approved by Robust Details Limited (RDL). CBA datasheet – Separating Walls

Section 2 of Approved Document E gives examples of constructions of separating walls for dwellings which should achieve the level of sound insulation required if the pre-completion testing route is to be followed.

Testing should be carried out on the first pair of dwellings on a site and thereafter at the rate of one test for every 10 dwellings provided there are no failures.

Section 6 of Approved Document E gives examples of constructions of separating walls for residential buildings which should achieve the level of sound insulation required.

To avoid the concern that a failure might occur if the pre-completion route for the testing of separating walls for dwellings is followed, it is common practice to use one of the many Robust Details for aggregate block constructions published by Robust Details Limited (RDL). Details of aggregate block Robust Details are available via the following links: CBA datasheet – Separating Walls  and http://www.robustdetails.com/.

The requirements for partitions required to meet the 40 R_w  dB value can be met by either:

• Building a specified approved construction given in section 5 of Approved Document E
• Pre-completion testing in accordance the regime identified in annex B of the Approved Document

Section 5 of Approved Document E gives examples of aggregate block constructions of partitions for dwellings which should achieve the level of sound insulation required.

Approved constructions to meet the acoustic requirements for partitions using aggregate blocks are:

• Plastered or drylined 100mm lightweight aggregate blockwork
• Plastered or drylined 75mm dense aggregate blockwork

Dense and lightweight aggregate concrete blocks can be used for constructions meeting the requirements of Section 5 of the Building Standards (Scotland) Regulations

The Scottish regulations require that buildings divided into more than one area of different occupation have to be designed and constructed in such a way as to limit the transmission of source noise from normal domestic type activities, between such areas, to a level that will not threaten the health of, or cause inconvenience to, the building occupants. This requirement applies to attached dwellings and to attached residential buildings.

The minimum value of airborne sound insulation required is:

56_DnT.w  (site tested value)

Three methods are permitted which can be used to demonstrate compliance with this minimum airborne sound insulation requirement:

• Use one of the example constructions given on the Building Standards Division website http://www.scotland.gov.uk/topics/built-environment/building/building-standards
• Use an acoustics expert to provide design guidance on constructions capable of achieving the required performance
• Use one of the Robust Details for Scotland approved by Robust Details Limited CBA datasheet – Separating Walls

Both of the first two methods require post-completion testing of separating walls of houses/flats/maisonettes in accordance with specific regimes according to whether or not the example constructions have been followed and the number of attached dwellings.

For new build using example constructions:

• For 2-20 dwellings – 2 tests are required
• For 21-40 dwellings – 3 tests are required
• For over 40 dwellings – 1 extra test for each extra 20 dwellings or part thereof

For new build using other constructions:

• For 2-10 dwellings – 2 tests are required
• For 11-20 dwellings – 3 tests are required
• For 21-30 dwellings – 4 tests are required
• For over 30 dwellings – 1 extra test for each extra 10 dwellings or part thereof

If it is preferred to avoid the possible concerns when demonstrating compliance by post-construction testing it is possible to use one of the Robust Details for Scotland. Information on the aggregate block constructions covered by this scheme are available via the following links:CBA datasheet – Separating Walls and http://www.robustdetails.com/other-services/robust-details-in-scotland

Section 5 also requires a minimum level of sound insulation between walls in dwellings and residential buildings between bedrooms and other areas except between an en-suite bathroom and the room it serves.

The sound insulation requirement is:

40 R_w  dB (laboratory tested value)

Compliance can be demonstrated by using one of the constructions detailed on the Building Standards Division website http://www.scotland.gov.uk/topics/built-environment/building/building-standards

Approved constructions to meet the acoustic requirements for partitions using aggregate blocks are:

• Plastered or drylined 100mm lightweight aggregate blockwork
• Plastered or drylined 90mm(min) dense aggregate blockwork

Under Revision

Under Revision

Cellular building blocks are proving to be a  hit with specifiers and blocklayers due to their lighter weight and ease of use. CBA members can provide cellular units within manual handling guidelines when solid units would  exceed the weight limit. The manual handling guidance seeks to protect site workers by restricting repetitive handling and lifting of units heavier than 20kg.

CBA members have responded with a range of design solutions including cellular blocks, which contain one or more formed cavities that do not fully penetrate the block. hollow blocks with voids which pass through the units are also available . As an example of the reduction in weight of cellular units, a typical standard dense cellular 140mm block can weigh up to 7kg less than its solid counterpart yet offers comparable  properties.

CBA Datasheet – Cellular Blocks

Masonry Design for Disproportionate Collapse Requirements under Regulation A3 of the Building Regulations (England & Wales)
This data sheet gives specific guidance on designing masonry structures in accordance with the disproportionate collapse requirements of regulation A3 as set out in Approved Document A.