Customize acoustic ceilings with specialty coatings

April 21, 2021

Photos ©[1]
Photos ©

by Ken Woolf, PE

It is possible to restore discolored, aged acoustical ceilings instead of replacing them with brand new materials when budget is limited or there are time restrictions.

Whether a ceiling is composed of an acoustical plaster or conventional ceiling tiles, the majority of aged acoustical ceilings are still structurally sound. The ‘less-than-new’ appearance is because of the deteriorated condition of the surface coating on the ceiling—it is no longer white because of exposure to ultraviolet (UV) light and/or contamination. Random water stains may have also degraded the appearance. In such instances, a new surface coating can be applied without compromising the favorable properties of an acoustical ceiling, such as sound absorption, and in the case of ceiling tiles, unimpeded access above the ceiling for maintenance purposes.

However, standard paint products should not be used for this purpose. Acoustical ceilings are designed to absorb sound. Standard paints bridge the pores of the material, thus inhibiting the sound absorption process. Further, and in the case of a suspended ceiling, the tiles are left stuck to the supporting T-bar system due to the dried paint, forming a film between the tile and T-bar. This compromises the ability to perform routine maintenance activities above the ceiling (i.e. electrical/telephone wiring and HVAC). Also, some paints can negatively affect the flame spread rating, an important design consideration.

Advanced acoustical coatings can modestly improve the sound absorbing quality of the ceiling and retard the flame spread (in case of a fire). In the white color, they disperse light sufficiently to reduce the dependence on artificial luminaires and have a longer life cycle than conventional ceiling paints, resulting in an impressive return on investment (ROI).

Acoustical coatings presently available have several capabilities including:

It is important to note all of the testing referenced by the author’s company was performed in their white color.


In the case of an acoustical coating, the following test results, referencing independent laboratories, should be easily provided by a reputable product manufacturer/supplier:

LEED credits

By restoring the existing ceiling materials and by using the qualifying acoustical coating, credits under the Leadership in Energy and Environmental Design (LEED) can be earned. To qualify, the coating must avoid or diminish solid waste disposal (recycling the old materials) and possess an acoustical coating with a low VOC rating (Credit 3.1 and 3.2 – Resource Reuse and Credit 4.2 – Low Emitting Materials: Paints and Coatings).

Structurally sound acoustical ceilings can appear aged and discolored  due to contamination, water stains, and exposure to ultraviolet (UV) light.[2]
Structurally sound acoustical ceilings can appear aged and discolored due to contamination, water stains, and exposure to ultraviolet (UV) light.

Installation is important

Every product is only as good as its installation. At best, it is risky to specify a product without assurance the application will be performed in accordance with the manufacturer’s recommended procedure. To ensure an applicator properly applies the product, specifiers and designers can utilize Section 09 51 23–Acoustical Tile Ceilings, which defines the requisite qualifications. It also spells out the consequences of substituting with an unauthorized product ‘equivalent.’

In the author’s experience, many of the common techniques used by the commercial painter negatively impact the absorption of sound because most contractors have not been informed of the need to maintain acoustical properties and are unfamiliar with the finer points of such a process. Further, they are not necessarily adept at protecting merchandise or furnishings in fully occupied spaces, a necessary requirement in the field of commercial property renovation.

In response, some acoustical coating manufacturers have developed a training program for contractors, specific to the application of their products in occupied spaces. Understandably, the applicators completing such a program satisfactorily are more likely to make a proper installation than others. Under the quality assurance (QA) portion of the guide spec, it is recommended that a trained applicator be identified with the provision the manufacturer of the specified product offers such a training program.

New construction

It must be acknowledged greater attention is now being paid to the benefits of using an acoustical coating on new construction projects as architects and specifiers are concerned with what many call “performance characteristics.” Does the product under consideration offer a level of performance that satisfies the project requirements? As an example, is the NRC at a satisfactory level? Is there a need for a Class-A fire retardant rating? What about toxicity in case of a fire? Is the physical size/shape of the product appropriate in the space provided? All these and other questions need to be answered by the architect before settling on a product that can be expected to perform as required.

Additionally, specifiers are concerned with the need to provide a design satisfying the “aesthetic standards” they wish to achieve. The acoustical product must have a shape and size that is appealing and appears natural in the space it is intended to occupy. The overall appearance is also dependent on using the proper mix of colors. Until the advent of the acoustical coating, color was a significant stumbling block.

Colors galore

Typically, acoustical product manufacturers are limited in the number of colors they can provide. The solution is to resurface the product with a coating tinted to a designer color. However, just as with the restoration of acoustical products, conventional paints cannot be used to provide the desired colors on new products without compromising the acoustical properties. This is not the case with an acoustical coating.

The better acoustical coating manufacturers have three formulations (product bases) for pastel, mid-tone, and deep-tone colors. In other words, any color—from white to black—can be produced as quickly as it takes to tint the appropriate base. The additional cost associated with the production and application of the coating is significantly less than the up-charge would have been if the manufacturer of the acoustical product had been able to produce the desired color. Further, there is very little wait time, as it takes a matter of days to tint the product and ship it out.

On some projects, the color-tinted acoustical coating is applied prior to shipping the product to the jobsite. In other instances, it is more practical to install the product first, and then spray the entire ceiling system with the coating at one time. When sprayed in place, the T-bars and air-diffusers can be coated at the same time for a more complete and consistent result. The approach taken varies from project to project.

Figure 1: The improved color of the walls and merchandise is a result of treating  the ceiling to a new white surface finish.   Images courtesy Ken Woolf[3]
Figure 1: The improved color of the walls and merchandise is a result of treating
the ceiling to a new white surface finish.
Images courtesy Ken Woolf

Acoustical wall panels

Acoustical panels mounted on walls can provide an excellent means of noise reduction. Under certain conditions, they can be treated with an acoustical coating either for purposes of restoration or by providing designer colors in new construction.

However, there are some limitations. The chemical formulation of an acoustical coating is significantly different from those of conventional paints. One of those differences is in the reduced use of binders and other elements affecting the surface tension. This is critical because the acoustical coating must leave the surface pores open in the material, as opposed to the harder paints that tend to bridge them. This brings the limitation to the fore. With the decreased use of binders, the result is a softer surface that does not hold up well to scrubbing.

On a ceiling, repeated scrubbing is seldom an issue, but on a wall where stains are common, maintenance personnel will frequently attempt to scrub the panels clean and wear down the coated surface. Therefore, the acoustical coating should not be applied where it may be subjected to scrubbing. The architect must decide what is the most important consideration—scrubability or acoustical performance.

With all of this in mind, architects wishing to maximize the sound absorbing areas will use the acoustical coating on wall panels down to a point approximately 2 m (6 ft) above the floor, and from there down, introduce another treatment. A contrasting paint color on a harder surface or even a paneling system (wainscoting) are examples of what can be done from the floor up to the 2-m level.

Honoring the spec

An architect specifies a particular product because it best satisfies the need for performance and appearance for a project. It is difficult when the specification is disregarded by someone down the line who takes it upon themselves to make an unauthorized substitution. It is an age-old problem particularly prevalent in the application of coatings of all sorts.

When opting for an acoustical coating, it should be noted inexpensive dry-fall paint can also be used if no consideration is given to the many negative effects on performance. To save money, many contractors will make the substitution, thinking no one will know the difference. This is frustrating to the architect, manufacturer of the specified product, and, ultimately, the end-user.

Some manufacturers have responded to this problem by developing CSI-formatted specifications for high-quality acoustical coatings, and then making them available to design professionals.

In the author’s experience, there is an improved conformance with the specified products when the CSI-formatted specs are used by architects. This appears to have been the best solution thus far to the extent many architects have begun using the same provisions regarding other products they wish to protect against unauthorized substitutions. It is advisable to ask the manufacturer if they have such a specification.

Benefits of a brighter ceiling

Many design professionals would maintain, in the white color, the most valuable characteristic of the better acoustical coating is the ability to disperse light sufficiently to reduce the dependence on artificial lighting. In Figure 1, it is easy to note the improved color of the walls and merchandise due to the ceiling having been treated to a new, white surface finish.

Quality coatings can hold the color longer than traditional ceiling-white paints, making for a more impressive life cycle, and have a better-than-average ability to disperse light. When the available light is dispersed effectively, it results in less dependence on artificial lighting (with an associated energy reduction), and particularly in a retail setting, merchandise seen in a truer color.

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