Soundproofing and Carbon Emissions Reduction Go Hand in Hand

The effort to meet new carbon emission goals includes reducing building thermal losses. The retrofit effort to improve thermal insulation is a perfect opportunity, with the help of an acoustical engineer, to also improve soundproofing for acoustically sensitive spaces, with very little additional cost.

UN climate change Summit (COP 21) in Paris was completed on 7-8 December, 2015. 196 countries had gathered to decide whether or not to commit to a low-carbon future in a legally binding way.

When applied properly in a wall assembly designed to reduce thermal loss, thermal insulation materials can also provide increased sound transmission loss through the wall assembly.

Types of thermal insulation improvements

Heat loss in a building is reduced by improving the thermal insulation of the building envelope, including exterior walls, windows, doors, and roofs. Read below how these thermal improvements can also improve the soundproofing of the building against exterior sounds (traffic noise, noise from night clubs, aircraft overflights, etc.).

Windows and doors

Windows and doors are typically the weakest point of soundproofing. Even if windows and doors are not being replaced, thermal loss and noise penetration improvements can be achieved simply by caulking gaps and replacing worn-out weather seals.

If windows and doors are being replaced, attention should be paid to the thermal specifications and acoustical specifications of the new windows and doors. Many reputable manufacturers provide information about STC value for their products.

Exterior walls

Generally, contrary to insulation manufacturers' claims, there is little difference between fiberglass and rock wool insulation products concerning their sound attenuation capabilities. When exterior walls are being upgraded to improve thermal insulation, attention should be paid to any cavities and voids in the walls. All voids should be filled with insulation, improving sound transmission loss of the walls.

If the energy loss retrofit plan calls for the removal and replacement of the interior skin of the exterior walls, the skin should be replaced with products and assemblies that reduce sound transmission.

Attics

Simply adding a layer of suitable thermal insulation in the attic will also improve sound transmission loss of the ceiling. Fiberglass bats add about 2 dB sound transmission loss per inch of the bat thickness [Ref. 1]. For example, if thermal insulation in the attic is increased from R-20 (6.5 inches) to R-50 by adding 9.5” of fiberglass insulation, the sound transmission loss of the ceiling assembly will be increased from about 13 dB to 32 dB.

Soundproofing as part of thermal insulation improvement

Any owner making building improvements to reduce heat losses, perhaps taking advantage of available government subsidies, should consider soundproofing improvements as the added benefit of the project. Engaging the help of a soundproofing consultant or acoustical engineer at the project's planning stages will ensure the maximum soundproofing benefit is achieved at the lowest possible cost.

[Reference 1:: Master Handbook of Acoustics, Sixth Edition (2015) by Everest & Pohlmann (McGraw Hill Education), page 303.