Soundproofing London Homes

Soundproofing London Homes

One of the biggest inducers of stress is domestic noise pollution, this is why Approved Document E of Building Regulations came into force, it stipulated clear and improved requirements for. As this is such an important issue for many inner-city residents, we look at what you need to know to account for good sound proofing and acoustic insulation to keep you and your neighbours happy.

Approved Document E (Resistance to Sound) of the Building Regulations sets out the soundproofing and precompletion sound testing standards for new and conversion developments. It deals with dividing walls and floors, but also covers sound insulation to internal walls and floors to protect the living areas such as lounge and bedrooms from noise. Part E also stipulates the sound insulation levels required to pass the sound testing for party walls and floors.

acoustic design and sound proofing for homes

Building Regulation Part E, covers England and Wales, are split into two sections:

                • Section E1 – looks at protection from noise from adjoining buildings including flats, terraces and semis-detached dwellings via separating partitions.
                • Section E2 – deals with sound transmission within the home via internal partitions.

Part E also divides sound into airborne sound and impact sound – two very different types of noise.

The minimum level of airborne sound insulation required for dividing walls or floors between new build homes is 45dB (decibels) for conversion projects 43dB is required. These levels should easily cut out normal levels of speech, TV and music playing to acceptable levels.

For internal partitions within a dwelling, the airborne sound resistance must be a minimum of 40dB – this applies to internal walls and floors between lounges, bedrooms and other rooms. If there is a door within the wall, it is accepted that you won’t usually achieve the required levels, so en-suite bathrooms usually fall into this category.

For impact sound such as footfall and dropped objects, a maximum impact sound transmittance level of 62dB is set for party floors and stairs in new build dwellings and maximum of 64dB for conversion projects.

What is airborne sound?

Airborne noise/sound is defined as any sound that is transmitted via the air, like speech or music. Sound waves are picked up and carried by air until they hit something solid, like a wall, floor, or ceiling. The collision sends vibrations through the wall and into the space beyond it. This is why you are able to hear music or shouting from neighbours.

What is impact sound?

Impact sound occurs when an object hits the floor partition, which generates sound that travels through a building, such as footsteps on a floor. Many common occurrences can cause impact sound such as people jumping and running, dropping objects. This has an effect not only on the rooms that are below, but to a lesser extent rooms either side as the sound can travel through the building as a result of the vibration from the impact. Impact sound is usually stronger (and more annoying) and its often more difficult to prevent, as it travels in different ways. Vibrations from the impact cause the sound to travel through ceilings and external walls.

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What if I have a Detached Property?

If you have a new detached property, you are not required to meet Building Regs Part E acoustic standards set for new attached dwellings, such as semi-detached, terraced and apartments.

For attached dwellings, developers have the choice of following Robust Standard Details, or carrying out on-site sound tests on dividing party walls between homes.

 

Design considerations for party walls and floors

To improve the chance of a successful sound test and reduce the chance of noise flanking you will need to ensure that you allow for the following five acoustic design considerations, when designing and constructing new floors and walls in flats, they are: Mass, Isolation, Absorption, Resilience and Stiffness

Why is Sound a Problem in dwellings?

Sound will always look for the path of least resistance. It can leak unexpectedly though tiny gaps, such as service penetrations for plumbing and electrics installations, or vibrate along fixing screws, bolts and nails. They are all pathways for sound transmission.

Even when you build a robust sound-resistant party wall or floor, noise often find a route around it. When sound bypasses a sound-resistant party wall or floor via an adjacent construction, this is known as flanking transmission and in our experience it’s more common than you might think.

 

Common Paths for Noise 

In our experience, these are the most common noise pathways:

                • Shared Structural Building Components – Floorboards, Floor Joists, Continuous Drywall Partitions, Continuous Concrete Floors, and Cement Block Walls.
                • Through Structural Steel – Structural steel beams are often a major cause of noise transmission as plasterboard is often fixed directly to the steel without sound breaks.
                • Plumbing Chases – Junctures between the Walls & Floor Slab Above or at the Exterior Wall Juncture (this should be filed with mortar etc. to add mass to these weakened areas.
                • Through Windows – if they have single glazing, with no double glazing or secondary glazing as a minimum and the windows are in close proximity either side of the party wall.
                • Fixtures & Outlets – Light Switches, Telephone Outlets, and Recessed Lighting Fixtures (if penetrations have been cut back-to-back with the opposite dwelling under test)
                • Structural Joints – Perimeter Joints at Wall & Floor, Through Wall & Ceiling Junctures (these should be filled with acoustic mastic.
                • Around the End of the Partition Through the Adjacent Wall (acoustic mastic should be used to seal this junction)
                • Chimneys – where flues serve open fireplaces between sound-resistant floors.
                • Service penetrations – for example, for plumbing pipes and wiring
                • Poorly poisoned socket outlets – placing the outlets back-to-back on walls, reducing the structure (mass) between them
                • Un-pointed mortar joints – with gaps and holes
                • Lack of isolating – in the ceiling void and floor void.
                • Hard floor coverings – without an acoustic resilient mat between them and the floor-boards. 

How to Combat the Problem of Noise flanking

Given our fondness for robust thermal insulation, the usage of timber frame and lightweight block walls is becoming extremely popular for residential projects. The inner leaf of a low mass cavity wall is an easy route for flanking transmission to bypass a sound-resistant wall or floor.

Overcoming noise flanking in timber frame developments, usually means double lining the walls with 15mm sound board; however, this process doesn’t always work for lightweight blockwork construction, so an additional independent wall may need to be installed, in front of the or inner leaves.

Poor positioning of window and door openings can also add to flanking transmission. Vibrations can be sent through the masonry wall between them, passing across the abutting sound-resistant wall. To tackle this, ensure the cavity is maintained along the party walls into the inner leaf of the envelope wall. Also, don’t position the windows right against the party wall, try and maintain at least 800mm between the openings.

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Where can I get good sound insulation advice for my project?

APT Sound Testing is a  UKAS accredited testing laboratory, and we have undertaken thousands of sound tests  to check the quality of the sound proofing in dwellings and we are seeing a rise in the amount of sound test failures due to poor acoustic design at the start of the project. In most cases if the client had instructing our acoustic engineers to undertake a preliminary acoustic design review of the project’s construction plans and section details it would have avoiding expensive remedial works, project handover delays and further build costs, as well as repeated precompletion sound testing.

Getting the acoustic design right from the word go, is key, and APT Sound Testing can help in all areas of sound insulation design and testing. Get in touch on info@aptsoundtesting.co.uk  to request a quote or call us on 01525 303905 to discuss your development.

Please Note: although we take every care to ensure the information was correct at the time of publication. Any written guidance provided does not replace the user’s professional judgement. It is the responsibility of the duty-holder or person carrying out the work to ensure compliance with relevant building regulations or applicable technical standards.