We often get asked by our clients in Northamptonshire and Buckinghamshire, how they can improve the sound insulation within Party Walls to pass the sound insulation testing. To try and simplify this we have written the following article explaining the main acoustic design considerations for undertaking the construction of party walls to pass the Sound Insulation Testing in compliance with Approved Document E.
Upgrading existing party walls in Northampton
To begin with you need to consider the following five basic acoustic design considerations, when upgrading existing walls in flats they are:
1. Adding Mass
2. Providing Isolation
3. Adding Absorption
4. Providing Resilience
5. Adding Stiffness
The main reason for Party Wall sound test failure in Northampton
The are many reasons why party walls fail the pre-completion sound testing for Approved Document E of Building Regulations, the main reasons are:
a. Shared Structural Building Components – Floorboards, Floor Joists, Continuous Drywall Partitions, Continuous Concrete Floors, and Cement Block Walls.
b. 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.
c. 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.
d. 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.
e. Fixtures & Outlets – Light Switches, Telephone Outlets, and Recessed Lighting Fixtures (if penetrations have been cut back to back with the opposite dwelling under test)
f. Structural Joints – Perimeter Joints at Wall & Floor, Through Wall & Ceiling Junctures (these should be filled with acoustic mastic.
g. Around the End of the Partition Through the Adjacent Wall (acoustic mastic should be used to seal this junction)
Acoustic wall upgrade for flats in Northampton
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 frame, then add 1 x 15mm & 1 x 12.5mm layers of soundboard to the outside of the met-sec frame. Ensure all boards are fully lapped and the perimeter joints are filled with acoustic mastic.
How many party wall sound tests do I need on Northampton Development?
Essentially, for sound testing party walls, you only need to carry out one type of sound test, which is airborne sound testing. If you development is 10 units or smaller you are required to carry out 2 airborne wall sound tests, if there are different types of wall construction you may need to undertake further testing to each wall type. 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.
Preparing your dwelling to pass sound testing through party walls
There are quite a few items to consider when preparing your development for the sound insulation testing. Basically, if you action the following items it should help you pass the sound testing at the first attempt avoiding costly delays and extra works: you should action the for the following checklist:
1. Download our APT sound testing checklist and tick off the items one by one.
2. The whole building envelope and internal walls and floors should be fully completed.
3. All external and internal doors and walls should be installed.
4. All external windows should be installed and closing properly.
5. All electrical fittings must be completely in-place, and fully functional. Poor electrical installation can lead to excess noise.
6. Standard 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
7. 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.
8. The skirting boards should not touch the floating floor, a flanking strip should be installed to prevent the noise flanking.
9. 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.
10. Access to all 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.
You need to action, all the above items, if we are to achieve accurate sound test readings. If any of them are ignored, there is a much greater risk of fail the testing.
APT can advise on all types of acoustic design to help you pass your sound testing to walls in Northampton flats, whether it’s accomplished during initial construction or during a refurbishment or renovation project. We are also a UKAS accredited sound testing, so you can be sure of a friendly and professional service providing a ‘one stop’ solution for all your acoustic requirements to achieve Building Control Sign off.
We undertake our acoustic consultancy services throughout Northampton and Northamptonshire, covering many areas including Cogenhoe, Kislingbury, Harpole, Brixworth, Sywell, Hackleton, Earls Barton and Blisworth to help you achieve the requirements of Approved Document E and attain building control signoff.
If you would like more information in regards to sound testing service and/or acoustic design services in Northampton, please contact us on 01525 303905 or info@aptsoundtesting.co.uk, for more information please visit our website at www.aptsoundtesting.co.uk or download our sound test checklist.