Tag Archives: Multi-family

Designing Sound Isolation in Multi-family Living

Acoustic_Rendering Twenty 20 Credit CBT Architects

Imagine moving into a new condo, only to realize the TV next door, the dog barking across the hall, and the neighbors walking around upstairs can all be easily heard. Acoustical consultants would love to help, but unfortunately there is little that can be done at this stage without significant cost and intrusion. Sound isolation issues are most effectively addressed before construction, during the design phase.

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How Thin is Too Thin?

Typical flat-plate construction. Photos courtesy SGH

Evaluating slab thickness in reinforced concrete flat-plate construction
by Dimitri Papagiannakis, PE

Reinforced concrete flat-plate construction is popular among mid- and high-rise residential construction projects. It provides a great deal of flexibility in the placement of the structure’s vertical load-carrying elements (i.e. columns and walls) without sacrificing the efficiency of the floor framing—as could potentially be the case with steel or masonry.

In the project’s early stages, structural engineers are often asked by architects …

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Improving Floor/Ceiling Sound Control in Multifamily Projects: Sound Testing Practices

The sound transmission class (STC) and impact insulation class (IIC) are ASTM-derived single number ratings that try to quantify how much sound a stopped by partition being tested. Laboratory testing involves an ideal setting for the floor/ceiling assembly—it is isolated from the walls, and there are no penetrations for HVAC, plumbing lines, sprinklers, can lights, or electrical boxes. In the field (i.e. F-STC and F-IIC), the floor/ceiling assembly often sits on load-bearing walls, is connected to the structure, and contains many ceiling and floor penetrations for the items just mentioned. Consequently, the code allows for a lower rating for field scores over those in the lab.

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Improving Floor/Ceiling Sound Control in Multifamily Projects


Demand for better floor/ceiling acoustics in multifamily construction has been spurred by consumer desires, new guidelines from code bodies, and stricter enforcement of existing codes. This article reviews important new guidelines, delving into how construction manufacturers have created new products or enhanced existing ones in the pursuit of achieving higher acoustical performance.

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Designing Floors for Optimal Performance: Understanding the impact of product choices and installation methods

All images courtesy Weyerhaeuser Trus Joist

When designing a wood-framed floor system for multi-family projects, from the joists to the subfloor, specifiers have numerous options for the level of performance related to occupant comfort. The size and thickness of floor framing materials, the way the members are laid out, and the manner in which they are installed have a direct influence on how stable the floor will be underfoot and how well the finished flooring on top performs over time.

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