Avoid Failing,
Use the 26 years experience in noise reduction and call for free direct on my mobile 07803 240 455, alternatively here are 10 ways to lower your risk of a failed sound test
- Design / Room Layout
- Know your limits / Acoustic Terms (Rw dB ratings)
- Floating Floors / Impact
- Wall Floor Junctions
- Correct insulation
- Flanking
- Doors / Lobbies
- Services / Back to back sockets / Recessed Lights
- Parallel Joists /Joist hangers
- Early Pre Sound Test of multiple Properties
1: Design / Room Layout…… If you are lucky enough to have a blank canvas then design your layout in such a way as to move bedrooms and lounge away from a dividing party wall, this can be done in a semi detached for example by having the entrance doors in the middle so that hallways and landings separate rooms of critical importance. We test lounge and bedrooms where available and stay away from bathrooms and corridors so use these none critical areas as acoustic barriers from the rooms that really count. When designing a multi room development via common areas such as corridors think about the positioning of the entrance doors to each dwelling, you would be suppressed how many failed tests have nothing to do with the wall or floor rather than to doorway into the premises.
2: Know your limits…… beware of Rw ! if you have been asked for a sound test by your building control officer, then its just like pulling a tooth, don’t have a go your self as it will most likely end up being very painful, take advantage of our free advice over the phone. There are so many issues that can arise when trying to gain a pass and comply with 43dB minimum noise reduction through party walls and floors, as well as the obvious how or what construction should I build, you have to also understand what labels are on products, Rw for example is a measurement of a product measured in decibels dB and is used as a reference only so that you can compare accurately against similar products, however this reference measurement does not include real world sounds that travel around the product, this is called flanking and Rw figures do not include this, so a product rated at 43dB Rw can be incorrectly assumed will pass the 43dB minimum for the airborne sound test, however you were not to know that you have to reduce the 43dB Rw by 8dB – 15dB to allow for on site flanking ! obviously this can be a costly mistake to make and it is made every day by clients who did not know there limits.
3: Floating Floors / Impact…… It is the easiest of the tests to correct if a fail has been recorded, usually a good resilient layer is added to the floor that has failed. In order to make the resilient layer work, it must float and if a 22mm chipboard is to float on top of a 10mm rubber crumb resilient layer then you must not screw the chipboard down, leave a perimeter gap, glue joints and let it float.
4: Wall Floor Junctions…… This is a more complex area of failed tests, many developers know what kind of wall or floor constructions normally passes a sound test, its the junction detail that can be a week link so seek advice regarding junctions.
5: Correct insulation…… There is so many types of insulation and some work extremely well with heat loss but are useless regarding absorbing sound, Celotext for example offers no acoustic absorption as its core is firm and the outer foil is hard, mineral wool on the other hand is soft and allows sound waves to pass through but the friction caused absorbs some of the energy.
6: Flanking…… in 2003 sound testing became mandatory, now many years later many developers are now mainly up to speed with basic construction types, however flanking is still one of the most common areas where we find failed sound tests, flanking is when sound travels around the wall or floor under test and bypasses all your hard work, in this example if your renovating then consider creating a new party stud wall on the top floor of the building creating two rooms for residential purpose, did you consider that the new wall you built sits on the floorboards and that the joists may run 90 degrees to your new shiny wall, here sound can travel under the wall and along through the floor joist voids flanking under the wall, obviously this should not happen as these routes should be blocked due to fire regulations but im afraid this is not always the case, the same flanking will be found over the top of your new wall if your wall stops under the loft ceiling plaster boards, if this is the case the sound can flank over the wall and through the loft space and into next door, again it should have a fire break but again it is not always the case.
7: Doors / Lobbies…… Doors are a weak area in any wall, we don’t as a rule test through a door unless is leads to a corridor, here the door can be upgraded from a normal 44mm fire door to a 54mm fire door, the door can have extra acoustic seals added and if necessary a second door with a lobby can be installed to increase noise reduction.
8: Services / Back to back sockets / Recessed Lights…… Service runs should be such that they do not penetrate walls or floors of rooms of critical importance, if you have a multistory building, run the services through stairwells lift shafts and corridors, only branch into the rooms of importance and back but not through the walls and floors between of these critical rooms. Regarding ceilings dividing apartments, do not install recessed lights, do not have back to back sockets in dividing party walls, try to keep the air tight integrity of the wall or floor.
9: Parallel Joists /Joist hangers…… If possible running joists parallel to a dividing party wall will help reduce sound paths that might otherwise travel along the joist and into the dividing party wall, if joists have to be at 90 degrees to the wall under test, use joist hangers and do not penetrate the wall face to use a a support for the joists.
10: Early Pre Sound Test of multiple Properties…… Try to arrange an early test especially if you have multiple properties to sign off, even with consultation it is always wise to have an early test carried out, we can get an idea of the performance of a wall or floor element once the plasterboards are in, we can temporary cover the doors and windows and use extension leads as is the case when we want to double check a new wall floor design.