What Is Acoustical Steel Deck?

Acoustical Metal Deck
What is Acoustic Deck? How Does it Work?

Acoustical metal deck are deck profiles that contain perforated holes in the flutes of the deck.

The flutes of the deck are then filled with a sound absorbing insulation materials so that when sound in the room travels to the decking, the insulation reduces noise by dampening the reverberation off of the decking.

Acoustical Metal Deck FAQs:

How does acoustical metal decking work?

It's practical solution for reducing noise within a building, The tiny perforated holes of the acoustical metal decking absorbs the sound through the acoustical insulation batts that is supported by the decking.

When does an acoustical metal deck get used?

Acoustical deck is best for use in gymnasiums, auditoriums, and theaters where noise reduction is required and desired by the occupants.

What is the difference between cellular acoustical and non-cellular acoustical?

Cellular acoustical metal decking has an additional flat plate attached to the underside of the decking profile. This additional plate is perforated and creates a finish aesthetic looks while maintaining the sound absorbing properties of standard or non-cellular acoustical metal deck.

Types of Acoustical Metal Deck

There are 2 common types of acoustical metal decking. They both maintain sound-absorbing NRC properties. Non-cellular, considered the standard acoustical metal deck and cellular acoustical metal deck. The main difference between the two types is that cellular acoustical metal decking has additional perforated flat metal plate welded or riveted to the bottom of the standard metal deck profile. This design creates a cavity where the acoustical insulation batts can be factory installed into the void created.

As this flat plate is installed it is therefore heavier, and consists of more steel per square foot, typically costing much more than a standard non-cellular metal deck product.

Non-Cellular Acoustical Profiles

Acoustical deck creates a sound absorbing roof system within buildings where the deck is exposed to the noise below. The most common acoustical metal deck profiles are the 1.5" B and 3″ N roof deck. The performance of these acoustical metal decks will be affected by the type of insulation placed above the deck. Therefore it's worth noting that the acoustical NRC data for these products is assumed to be rigid fiberglass insulation board, polyisocyanurate insulation (poly-iso) board, and with roof board.

1.5" BA [Acoustical]

B Acoustical Deck

  • Standard Roof B Profile
  • Acoustical Perforations Inside the Flutes
  • Insulation Install Typically by Roofing Contractor

3.0" NA [Acoustical]

  • Standard Roof N Profile
  • Acoustical Perforations Inside the Flutes
  • Insulation Install Typically by Roofing Contractor

Cellular Acoustical Profiles

Cellular decks are also manufactured in an acoustical version.  One of the key differences of a cellular deck is that the insulation comes pre-installed by the manufacturer. The insulations batts are placed on top of the flat bottom plate with acoustical perforations underneath the profiles flutes. The insulation placed above the deck has minimal impact on the acoustical properties of the metal decking so it is common to see only poly-iso is used in these roof assemblies.

1.5 BCA [Cellular Acoustical]

  • Standard Roof B Profile
  • Bottom Flat Plate with Acoustical Perforations
  • Insulation Factory Installed

3.0" NCA [Cellular Acoustical]

  • Standard Roof N Profile
  • Bottom Flat Plate with Acoustical Perforations
  • Insulation Factory Installed

Acoustical Metal Decking Gauges

The metal deck gauge is a unit of measurement that refers to the thickness of the steel.  The higher the gauge number the thinner the steel. The lower the gauge number the thicker or heavier the steel is.

Example 1: 18ga B deck is thicker, and therefore stronger and thus heavier than 22ga B Deck.

Example 2: 22ga B decking is thinner, and therefore lighter and thus weaker than 20ga B Deck

What Gauge is Acoustical Metal Deck?

The (EOR) or Engineer of Record should be dictating the acoustical decking gauge for the specific project . However, typically the deck gauge will depend on the below factors calculated by the engineer of record:

  1. Load capacities and/Concrete slab capacities
  2. Span capabilities of the deck during or after construction
  3. Diaphragm shear values

What is unique about cellular metal deck is that the flat plate gauge may or may not match the profile gauge.

Cellular metal deck is notated using a / to dictate the gauge of the profile and bottom plate.

Example: 1.5 BCA 18/20 G-60.

In the above example the metal deck B decking profile will be manufactured as 18 gauge while the bottom plate is only specified to be 20 gauge.

Acoustical Metal Deck Finishes

The finish of the material used for acoustical deck products is most commonly one of the two options below. It's important to note that typically in new construction the finish is dictated by the engineer and/or specifications. This typically isn't an option, but a requirement when ordering acoustical deck. Thus, be sure to check your roof deck specifications or bid documents before placing an order.

Finishes are typically galvanized or galvanized with a prime paint.

Galvanized finish

Galvanized steel deck exposed to ordinary atmospheric conditions in the standard base coil galvanized coating of either G-60 or G-90.

Galvanized & Prime Painted Bottom Finish

Standard base coil with galvanized coating in G-60 or G-90 with an additional baked on enamel primer paint in grey bottom or white bottom for aesthetics or field application.


ASTM Specificaion A653 A1008 A1008 A653 A1008 A1008
Cellular Decking X X
Acoustical Decking X X

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    Icon G-60 Galvanized Metal Deck


    The zinc coating acts as the protective barrier between the steel and the environment. Typically deck specified as G-30,G-60 or G-90.

    Galvanized Base & Primer Painted 

    Galvanized (G-30,G-60, G-90) base coil with a special baked on enamel primer paint in grey/grey or grey/white .