noise between spaces is frequently an issue in residential projects
and office spaces. Noise will travel between spaces at the weakest
points, such as through a door or outlet. There is no reason to spend
money or effort to improve the walls until all the weak points are
General rules of thumb for controlling noise
- A wall must extend to
the structural deck in order to achieve optimal isolation.
Walls extending only to a dropped ceiling will result in inadequate isolation.
- Sound will travel through the weakest structural
elements, which, many times, are the doors or electrical outlets.
the mass of a barrier is doubled, the isolation quality (or STC rating) increases
by five, which is clearly noticeable.
insulation within a wall or floor/ceiling cavity will improve the STC rating by
about 4-6 dB, which is clearly noticeable.
times, specialty insulations do not perform any better than standard batt insulation.
- Metal studs perform better than wood studs. Staggering
the studs or using dual studs can provide a substantial increase in isolation.
- Increasing air space in a wall or window assembly
will improve isolation.
Newspaper office building
Area of concern: Space between CEO office and
Additional information: Noise usually travels through spaces
at several different points. Controlling only one point is like trying to save
a sinking boat by patching only one hole when 10 holes exist. You must be thorough
to ensure effective results.
Questions to ask client:
- Please describe the problem.
the wall go all the way up to the deck and is it sealed airtight? Does it just
go up to the dropped ceiling? Are there any penetrations through the wall?
- Are there any penetrations through the wall?
the noise be going around the wall? Are there any air gaps? Under the door? At
the perimeter of the wall? At the window mullion? Etc?
materials are used in the space(s)?
- What are your
- The CEO is distracted by noise from the boardroom when
there are meetings in progress. There are also confidentiality issues.
- The wall does not go up to the deck, it ends at the dropped
- There are no penetrations other than the
- The noise could be going around the wall
by means of the door.
- The materials used in this
space are carpet, painted drywall and acoustic tile on the ceiling. There are
two return air ducts about two feet apart, separated only by the wall.
- Confidentiality is an issue to some degree, but not a security
Evaluation: In this particular
project, there was a door and a window between the two spaces and the ceiling
did not go up to the deck. To improve the acoustics, an upgraded sealer was added
to the doors and a flexible, vinyl barrier was placed on top of the ceiling above
the two spaces (since the wall could not be extended to the deck). Creating a
completely confidential space is very difficult and extremely expensive. Since
confidentiality was an issue, but not a security matter, this improvement proved
If further improvements were needed, the next step would
be to install a sound masking system.
comments: In another office space, where complete confidentiality was essential,
a very expensive door was installed. This door had an STC rating of 65, but the
surrounding walls had an STC rating of 50. In this case, the walls served as the
weakest point, rather than the door. Its important to note that the isolation
quality of an assembly is dictated by the weakest element of the assembly.
For more information on Sound Transmission Class, visit STCratings.com.