Condo Noise: Re-evaluate that Flooring Underlayment

Canada’s housing market has cooled amid rising interest rates but you wouldn’t necessarily know it by the pace of condominium construction in the country’s biggest cities. Yes, pre-construction sales have plunged in recent months, but those projects with shovels already in the ground are forging ahead. This makes it an ideal time to discuss the elusive and misleading world of acoustic floor membranes as they pertain to this multi-residential sector.

Sound travels faster through hard materials like wood and concrete than it does through air — 8,859 miles per hour (mph) versus 767 mph. Vibrational noise through a building structure, not airborne noise, is what causes many soundproofing issues in condos. This is where the improper installation of acoustic floor membranes comes in as it is often behind noise complaints in these buildings.

Underfloor treatments are normally recommended or required by code for new condo projects. Many condo corporations also require these treatments in existing condos and that they can achieve an acoustical soundproof standard of a minimum field impact insulation class (FIIC) rating of 70. There are several reasons for doing so, including improving the sound character of a room and putting less impact noise and vibration energy into the building structure itself. Acoustic membranes are used to achieve this goal. But they are one of the most misunderstood products in homebuilding and renovations today.

In a condo, an acoustic floor membrane is installed over the concrete slab and under the finished floor. In short, the layer of material increases the overall density of the floor/ceiling assembly. Its sole purpose is to control impact sound — generated by walking, dancing, exercising, moving furniture and other activities that send shock waves through the floor — and vibration.

In Canada, acoustic membranes ought to be field tested (FIIC) over an eight-inch concrete slab with no suspended ceiling to offer the best results. However, a 2020 case study found the overwhelming majority of acoustic floor membranes installed by contractors did not meet these requirements.

Why?

Because most sold in today’s market are laboratory tested to an impact insulation class (IIC) rating, with a suspended ceiling often consisting of resilient channeling, isolation clips, four to six-inch sound batt insulation and one to two layers of drywall. Obviously, these products test exceptionally well. However, once the excessive materials are stripped away — none of which exist in most condos — the acoustic rating drops by up to 50 per cent.

This only partly explains why less than ideal acoustic floor membranes are installed in condos. The other reason comes down to cost.

The flooring market is one of the most competitive industries. Look no further than the exponential growth of flooring retailer showrooms in any given neighbourhood, at least in the Greater Toronto Area. So, it’s ‘understandable’ when a contractor does not include a $2 per square foot superior, four-millimetre (mm) rubber product in its project bid when tendering against two to three others. Instead, it’s very common for contractors to quote a 1 mm Styrofoam product made in the Far East that’s just 10 cents per square foot and claims to offer exceptional acoustic results.

It’s prudent that flooring professionals take a closer look at the acoustic membranes they’re using. Rubber membranes are considered superior when it comes to impact sound control and not just in the flooring industry. These products are utilized to isolate vibration under heavy mechanical equipment, gym floors, dance floors and playgrounds, not cork, cloth or Styrofoam. Condo flooring is no different when the desired outcome is to mitigate impact noise and vibration.

Adhesives that claim acoustic ratings are also quite common these days. They are almost always tested with a gypsum suspended ceiling. (The data sheet will often read ASTM E-492-04 IIC 65, 150 mm concrete slab with suspended gypsum ceiling.) Installers should be mindful of this before deciding to forego an acoustic membrane in the hopes the glue will provide adequate impact sound protection all by itself.

Flooring professionals interested in reducing noise and vibration in condos would be wise to use rubber soundproofing as a first step. Affordable recycled rubber products can be easily purchased nationwide. What’s more, most qualify for LEED (Leadership in Energy and Environment Design) credits that are attractive to developers and architects looking to meet eco-friendly project goals.

Steve Vasconcelos is owner of The Floor Studio Inc., a supplier of specialty hardwood, engineered flooring, luxury vinyl tile and sound attenuation products. Steven is also an accredited National Wood Flooring Association inspector with more than 25 years of experience in the flooring industry that includes analyzing acoustic test reports and membranes. He can be reached at 416-533-2855 or [email protected].