By Robert “Bob” Marshall, P Eng., BDS, LEED AP
Continuous urban population growth in recent years has created one common problem in cities throughout Canada (like Vancouver) – noise complaints and affordability concerns.
Currently, the National Building Code of Canada (NBCC) requires low-rise and high-rise residential construction projects to achieve a minimum STC rating of 50 in wall assemblies separating two residential units and corridors, and a rating of 55 for elevator shaftwalls that border a living space.
The good news is that these ratings can be achieved with the right mix of high-performance gypsum wallboards and sound-absorbing or sound-dampening materials in a wall assembly.
Building double-stud walls or installing multiple layers of gypsum board can also be effective, but can be costly. And, incorrect placement of the boards can compromise the noise-reducing abilities of the wall assembly. These configurations often increase the footprint of the wall, which reduces the usable square footage of the floor plan. With Toronto condo prices now averaging $382,070 and a typical townhouse in Greater Vancouver now costing $563,700, more efficient use of floor space can yield real estate rewards of several thousands of dollars.
Fortunately, the emergence of new technology has enabled building product manufacturers to introduce more practical, smarter options for sound control in wall assemblies. One better solution is laminated core noise-reducing gypsum board.
The first step in writing specifications for laminated core noise-reducing gypsum board including noise-reducing fibreglass insulation in the cavity is calculating the sound rating needed for the building’s wall assemblies and designing them accordingly.
In this process the following options should be considered:
- Thickness: 12.7 mm (½-inch) or 15.9 mm (5/8-inch) Type X
- Widths: 1.2 m (4-foot) ; Lengths: 2.4 m (8-foot) or custom
- Edges: Tapered
The second step is to compare single layer laminated core noise-reducing gypsum board systems against other contemporary 4-layer gypsum board systems. By inputting project -specific material and installation costs and collaborating with manufacturers’ field sales representatives, building and design professionals can determine a customized comparison of the cost/sq. m. (sq. ft.) for the wall assemblies.
The final step is to calculate the extra real estate rewards from thinner laminated gypsum walls. CertainTeed /Saint-Gobain has a calculator tool that can be used for this purpose. For example (See illustration), using recent Vancouver average condo price of $436,546 and a 93 sq. m. (1,000 sq. ft.) condo area, it is estimated an extra profit of $2,145.21 and $1,854.41 (for a total of $4,000) are possible by using laminated core noise-reducing gypsum vs. double layer 15.9 mm (5/8”) Type X and 12.5 (1/2”) resilient channels respectively. Real estate rewards will vary depending on the market where the analysis is based. In Toronto, the average condo price is $382,070 CDN but these Canadian costs look affordable compared to San Francisco @ $1.0 million US and New York @ $1.7 million US.
Laminated core noise-reducing gypsum boards provide a cost-effective solution to any project where sound control is a top priority. With STC ratings that meet or exceed the acoustical performance of traditional multi-board acoustical wall assemblies, assemblies with laminated noise-reducing gypsum boards reduce material usage and are therefore quicker and easier to install and considered more sustainable. Consolidating all of these sound dampening abilities into one board also conserves valuable floor space, an important consideration in the burgeoning real estate markets of today’s Canadian cities. And, as an added benefit, laminated noise-reducing gypsum boards also have moisture- and mould-resistant face and back papers to ensure good indoor air quality.
The results of this combination are smarter sound control project cost savings and optimal indoor environmental quality for the well-being of building occupants–a combination that should be included on all of your projects.
For more information please visit http://blog.certainteed.com/2016/04/building-smarter-firewall-fire-separation-and-sound-control-assemblies or to customize for your project please contact the writer or our regional architectural solutions managers or call our toll free Professional Line 800-233-8990.
Bob Marshall is building science manager for CertainTeed Gypsum Canada and can be reached at email@example.com. He has been appointed by NRC to the Standing Committee on Energy Efficiency in Buildings.