Property and building managers are continuously looking for ways to reduce sound and noise complaints in their buildings. When they go out there into the world to find answers, they get a whole mish mash of opinions and solutions.
I am going to try to take the mystery out of sound transmission complaints and remediation.
When it comes to soundproofing there are two types of ratings used, STC and IIC ratings.
STC (Sound Transmission Class). This rating measures how well a building partition like a wall or a window provides a reduction of sound decibels. A higher number indicates more effective sound insulation than the lower number. The STC rating is useful in wall assemblies as it prevents common noises like loud talking from penetrating walls. However, it is not particularly useful for impacts, music, or machinery noise as these are more low frequency sounds.
IIC (Impact Insulation Class). IIC is a way for sound technicians to quantify how well your floor blocks impact noises. These are the noises from people interacting with flooring products. Impact noises are soundwaves that travel through solid materials and common examples are footsteps, moving furniture, or things dropping on a flooring surface. The IIC is the acoustic rating that rates how well a floor assembly blocks impact vibrations. The higher the IIC Rating, the better the assembly is at blocking impact noises. The minimum requirement in the building codes of most Canadian jurisdictions is an IIC of 50. Some assemblies, especially those with flooring underlayment’s, can reach an IIC rating in the 80s.
What does this all mean?
Property and building managers constantly struggle with complaints from unhappy tenants about noisy upstairs neighbors. A high scoring IIC floor rating is crucial because it reduces impact noises, resulting in a more comfortable and tolerable lifestyle for owners and tenants.
Joist floorings offer more impact noise reduction than bare concrete flooring due to the large noise absorbing airspaces.
Note: the simplest way to improve your floor assemblies IIC rating is by adding an underlayment, which is a rubberized layer of fabric you place between the subfloor and the surface layer. Rubber is a dense material, dependable, and is excellent at absorbing impact noises.
In today’s ever changing décor environment, owners of strata lots should seek to achieve and prove an IIC rating of at least 72 when installing new flooring products. This will improve livability and reduce complaints.
With a little bit of care and good advice, Strata and Property managers can advise their strata councils to plan their renovations to reduce noise transfer complaints and improve lower floor livability.
Let’s have a look at ways to improve your floors IIC ratings by tackling how your floor is installed:
APPROXIMATE ICC RATINGS WITHOUT UNDERLAYMENT (JOIST CONSTRUCTION) | WITH RECOMMENDED UNDERLAYMENT – (JOIST CONSTRUCTION) |
Tiles 40 IIC | Sound deadening can be achieved even with tile. Use a system with a sound deadening membrane embedded in the tile mortar base. Good choices are the Schluter Ditra Heat Duo uncoupling membrane, and the Sound Guard Easy Mat membrane by Custom. In all cases, have your contractor install perimeter movement joints to isolate the tile installation from flanking sound transfer. An excellent choice is a perimeter movement joint made of sill gasket or a joint profile like the Schluter ‘Dilex BWA PVC’ |
Hardwood Flooring 47 IIC | A desirable choice for sound deadening is a membrane made by ‘Acoustitech’ and gives the necessary 72 IIC sound rating under glue assist or floating hardwood installations. |
Vinyl Flooring 47 IIC | Vinyl floorings offer a huge choice of decors and styles out there from stone tile looks to your favorite wood patterns. They come in sheets, planks, and tiles. Installation can be glued down while others click together. By far the best choice are the thicknesses of 6.5 mm and above. You can purchase “click” together planks and tiles with a rubberized or cork sound deadening layer bonded to the back. Most offer 72 IIC or higher. |
Laminate Flooring 48 IIC | A foam rubberized underlayment such as Atlanta Flooring’s ‘Super Silent’ underlay with a rating of 73 IIC, or the ‘Big Blue’ underlayment with a rating of 77 IICs must be installed. There are newer laminate floorings on the market that come with the pad already bonded to the back such as Atlanta Flooring’s ‘Lamdura’ series. |
Plywood 55 to 58 IIC | |
Concrete 56 to 58 IIC | |
Carpet with underlay 75 to 85 IIC | Carpet remains an excellent choice for bedrooms and stairways. Property managers should advise strata corporations to use an 8 lb density of at least 9-11 mm chip foam such as Atlanta Flooring’s ‘Rebond’. |
Reference for Strata/Property Managers
Laminate flooring: Waterproof with an underlayment meeting IIC 72 or higher.
Vinyl plank/tile flooring: Use either a pad bonded to the back or in rolled underlayment format meeting an IIC 72 or higher.
Carpet: Use a 9 mm to 11 mm chip foam underlayment for sound deadening.
Hardwood: Use a manufacturer approved underlayment meeting IIC 72 or higher.
Porcelain tiles: add a sound deadening membrane embedded into the mortar bed base as well as perimeter movement joints.