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Choosing Acoustical Insulation Products

acoustical wall

Acoustic insulation is an important consideration when choosing construction materials. It provides a more comfortable environment in the home and a more productive atmosphere in the workplace. Therefore, acoustical insulation plays a vital role in both residential and commercial construction. Since sound has the ability to travel through a variety of mediums, the type of materials used will vary depending on the application. Building codes often stipulate that construction materials meet specific criteria for sound control. It’s essential tounderstand the properties of the materials prior to requesting an acoustic insulation delivery.

Sound Reduction Index (R)

Acoustic insulation materials are tested and assigned a variety of indexes that define their ability to absorb sound. One of the most common is the Sound Reduction Index (R). The value is derived in a laboratory environment where the noise level is known and is expressed in decibels (dB). The higher the index, the greater the sound absorption properties demonstrated by the material.

Sound Transmission Class (STC)

Sound recording studioThe American Society for Testing and Materials (ASTM) developed testing to determine the ability of building constructs such as walls, doors and ceilings to reduce sound. The loss of sound transmission is determined over a range of frequencies from 125 Hz to 4000 Hz. These values are reasonably accurate for vocal sound but much less so for frequencies below 125 Hz such as noise from traffic, aircraft or music. STC values range from 25 to 72. At an STC of 25, normal speech can be heard and understood through the construction material. An STC above 60 provides soundproofing that eliminates most sounds. In Boston, building codes require a minimum STC of 50.

Blankets and Batts

Blanket or batt acoustic insulation is typically comprised of fiberglass or other synthetic or natural fibers that are interwoven to produce materials of varying density. It is typically a couple of inches thick and found in rolls of material approximately 8 feet long.  Batt acoustic insulation can be used for sound dampening in walls, ceilings and flooring. Since porous materials are more effective at absorbing sound, the highest density insulation doesn’t produce the optimal sound control. Batt insulation with a density ranging from 2.5 to 3.0 lbs/ft3 is most effective for sound insulation. It is lightweight and easily managed. Depending on the construction method, it can improve STC ratings by 4 to 10 dBs. It also has the additional benefit of providing thermal insulation.

Acoustic Panels

Acoustical Ceiling PanelsAcoustic panels are constructed of gypsum or mineral fibers and enclosed in an ornate material. Foam acoustic panels are usually the most economical. Acoustic panels are designed to absorb sound within a specific area to moderate resonance. They can be used on walls or ceilings. The effective sound transmission loss depends on the thickness and material used for construction. Some materials are more effective at absorbing certain frequencies than others and are rated by ASTM sound absorption coefficients at wavelengths from 125 Hz to 4000 Hz. On average, a 2 inch acoustic panel has an STC of 37 while a 4 inch panel has an STC of 48. They are most often employed in cafeterias, conference rooms and recording studios.

Drywall Panels

Acoustical drywall is constructed of gypsum board and is frequently enhanced with other materials including concrete or metal. Careful consideration should be given to where drywall panels containing these materials are installed since they may interfere with cellular phones and other wireless devices. Additional layers of drywall are often added to improve sound control. Acoustical drywall can be used for ceilings and walls. It is resistant to mold, and most types have an STC rating of 55 or greater.

Viscoelastic

Viscoelastic materials are synthetic polymers that reduce sound transmission by transforming its vibrations to heat energy that is dispersed into the air. This material is inserted between layers of drywall, plywood or cement board to reduce the noise transferred between rooms. Viscoelastic materials can decrease sound transfer between rooms by as much as 10 to 20 dBs.

A wide selection of acoustical insulation products is available online. It provides convenient access to quality materials of all types from companies that offer insulation delivery in Boston directly to the construction site.


Making Walls Quiet Whitepaper CTA

Photo credit: lglazier618 / Foter / Creative Commons Attribution 2.0 Generic (CC BY 2.0), urban10 / Foter / Creative Commons Attribution-ShareAlike 2.0 Generic (CC BY-SA 2.0)

Sources: http://hardwoodfloorsmag.com/articles/article.aspx?articleid=50&zoneid=2 , http://www.wisegeek.com/what-is-acoustic-insulation.htm , http://www.isover.com/Q-A/Choice-of-insulation-material/How-to-choose-acoustic-insulation

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Wallboard Supply Company is a third generation, family run business that has been serving New England's building needs since 1970. Bob Filion started the company with a commitment to provide quality drywall and finishing products with unmatched customer service. The company has grown over the years, expanding its' product range, but never wavering from its' core values.