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 upgrading an existing floors and walls in flats they are: 

1. Mass
2. Isolation
3. Absorption
4. Resilience
5. Stiffness

Reasons for party walls failing sound testing in Flats

The are many reasons for party walls failing the pre-completion sound testing for Part of Building Regulations, the main reasons are

1. Shared Structural Building Components – Floorboards, Floor Joists, Continuous Drywall Partitions, Continuous Concrete Floors, and Cement Block Walls.
2. 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.
3. 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.
4. Through Windows – if they have single glazing, with no double glazing or secondary glazing as a minimum.
5. Fixtures & Outlets – Light Switches, Telephone Outlets, and Recessed Lighting Fixtures (if penetrations have been cut back to back with the opposite dwelling under test)
6. Structural Joints – Perimeter Joints at Wall & Floor, Through Wall & Ceiling Junctures (these should be filled with acoustic mastic.
7. Around the End of the Partition Through the Adjacent Wall (acoustic mastic should be used to seal this junction)

Acoustic wall upgrade for Existing Flats

One way to quick and simple way improve the acoustic performance of a dividing wall partition, is to install a 70mm met-sec partition in front of the existing wall – it is usually best to install this in the largest room. Leave approx. 25mm gap between the back of the met-sec and the wall. Then install 50mm acoustic wool (min 45kg/m3) to the inside of the met-sec and add two layers of 12.5mm soundboard to the outside of the met-sec frame. Ensure all boards are fully lapped and the perimeter joints are filled with acoustic mastic. 

What Sound Tests do I Need on My Party Walls.

Essentially, for sound testing party walls, you only need to carry out one type of sound test,  which is airborne sound testing. For floor partitions you are required to carry out two types of sound insulation tests which are airborne and impact sound insulation tests. The airborne sound insulation test is carried out by means of a loudspeaker emitting a steady source of noise on one side of the partition (wall or floor) to be measured

How Should I Prepare my Dwelling to Pass the Party Wall Sound Testing?

It is easy to prepare your new project for the sound insulation testing to your party walls, basically you should action the for the following checklist: 

1. The whole building envelope and internal walls and floors should be fully completed prior to the undertaking sound testing.  
2. All external and internal doors and walls should be installed.
3. All electrical fittings must be completely in-place, and fully functional. Poor electrical installation can lead to excess noise.
4. 240 volt power should be in-place and available in every room. Our testing equipment can be damaged  by the voltage fluctuations of on-site power generators, so it’s essential to have 240V mains supply on-site on the day of the test
5. No carpets or laminated flooring should be fitted on the 1st floor levels or above. These materials can affect the movement of noise, and as a result could impact on whether a building passes the sound check test.
6. The skirting boards should not touch the floating floor, a flanking strip should be installed to prevent the noise flanking. 
7. All gaps in the walls and floors should be sealed. Again, noise can leak out through any gaps, affecting the movement of sound and impacting on the space’s performance.
8. Access to all of the rooms on all levels should be granted to our technicians, with all noise sources (radios, alarms, building work) ceasing for the duration of the test.
9. The above points are all essential if we are to achieve accurate sound test readings.  If any of them are ignored, there is a risk of you either failing your test or – at worst – not being able to complete it, at which point you may still be charged 75% of the test fee.

We can advise on all types of acoustic design to help you pass your sound testing to walls in flats, whether it’s accomplished during initial construction or during a refurbishment/renovation project. We also undertake UKAS accredited sound testing providing a ‘one stop’ solution for all your acoustic requirements. 

If you would like more information in regards to sound testing please follow our blog at: http://soundtestinguk.blogspot.co.uk. Alternately, if you would like more information on how to prepare for your sound testing please download our sound test checklist.