When evaluating the prospective location for a multi-family residential project, there are many factors that should be considered. Chief among them is a factor that is often overlooked: potentially intrusive existing noise sources around the building site. Here in the greater Boston area, Acentech has consulted on several residential projects along major transit lines. Noise from the Mass Pike and other highways, the commuter and light rail system, and Boston’s Logan Airport bombard building façades with high levels of noise. Special consideration is needed to ensure that noise from these modes of transit is addressed appropriately. And while it’s true that robust façade constructions on residential buildings near high-traffic areas are often imperative for the comfort of residents, they can also result in significant additional costs to the project if overdesigned.
With any residential project site near road, rail, or airport noise sources, the construction of the building envelope is especially crucial to the design process. From an acoustic standpoint, the window construction is most critical in achieving the desired overall sound isolation performance of the envelope, since windows typically have lower sound isolation ratings than standard exterior walls. In many cases, a typical 1-inch insulated glazing unit is not sufficient to attenuate exterior transit noise to an acceptable level. Varying the thickness or number of the lites, upgrading to laminated glass, or increasing the airspace between lites all impact the overall sound isolation capabilities of the window assembly. Modifications to one or more of these elements of the window are often necessary to attenuate transit noise. On one hand, specifying windows that do not provide the necessary level of sound isolation may result in disturbed and angry residents; on the other hand, installing a window with an excessively high sound isolation rating has diminishing returns, and can add unnecessary expense to the project.