Whether you are an architect specifying acoustical plaster, a contractor preparing a bid, or a homeowner exploring home acoustics, this page is designed to answer your questions about seamless acoustical plaster and BASWA acoustic systems. Browse by topic or use the section links below to jump to the answers you need.
Get Started
When evaluating an acoustical plaster system, always request third-party test data measured in accordance with ASTM C423, the Standard Test Method for Sound Absorption and Sound Absorption Coefficients by the Reverberation Room Method. This is the authoritative standard for measuring sound absorption in the architectural products industry. Results should report absorption coefficients at individual octave-band frequencies as well as the single-number Noise Reduction Coefficient (NRC) and Sound Absorption Average (SAA) ratings.
BASWA systems are tested per ASTM C423 using both A-mounting and E-mounting configurations to accurately represent the range of real-world installation conditions. This dual-mounting test approach provides the most reliable prediction of installed performance across different project types.
Download third-part test data for BASWA systems.
High frequency sound absorption is accomplished by allowing sound wave energy to pass through the micro-porous finished surface of a BASWA System, thereafter dissipating into heat energy in the mineral wool panel. When low frequencies hit a BASWA System, the surface vibrates like a diaphragm. These vibrations are then converted to heat energy as well. BASWA Phon has a noise reduction coefficient rating up to 1.00, unmet by other products. This reduction of mid-range and extreme high or low frequencies allows for clearer sounds in any room, hall, atrium, or auditorium. BASWA Phon absorbs consistently high in all frequencies. Learn more about how BASWA Systems perform.
Reverberation time (RT60) is the time, measured in seconds, that it takes for a sound to decay by 60 decibels after the source of that sound has stopped. It is one of the most important metrics in architectural acoustics because it directly affects speech intelligibility, listening comfort, and occupant wellbeing. Rooms with long reverberation times, such as hard-surfaced lobbies, gymnasiums, or open-plan offices, produce overlapping sound reflections that make speech difficult to understand and create a fatiguing acoustic environment. Research published in peer-reviewed acoustics literature consistently links excessive reverberation to reduced speech intelligibility and negative effects on occupant concentration and stress levels.
Acoustical plaster reduces reverberation time by converting reflected sound energy into heat rather than allowing it to bounce around the room. The appropriate target reverberation time varies by room type and use.
The Noise Reduction Coefficient (NRC) is a single-number average of a material's sound absorption coefficients at 250, 500, 1,000, and 2,000 Hz, measured per ASTM C423. The scale runs from 0.00 (perfectly reflective) to 1.00 (perfectly absorptive). BASWA systems achieve NRC ratings from 0.80 to 1.00 depending on system thickness and finish selection.
The Sound Absorption Average (SAA) is calculated as the average of measured sound absorption coefficients at 12 one-third octave bands from 200 Hz to 2,500 Hz, rounded to the nearest 0.01. It provides a broader frequency picture than the NRC, which averages only four frequencies. Both are measured per ASTM C423.
Sound absorption and soundproofing address two different acoustic problems and should not be confused. Sound absorption reduces the amount of sound energy reverberating within a room. When you add absorptive material, you reduce echo, reverberation, and ambient noise levels inside that space. Soundproofing, or sound isolation, reduces the transmission of sound from one room to another through a wall, floor, or ceiling assembly.
While BASWA systems are specified for sound absorption, they can also contribute 5 to 7 points to the Sound Transmission Class (STC) rating of a wall or ceiling assembly when installed in conjunction with products designed for sound isolation, making it a complementary part of a comprehensive acoustic strategy.
For a thorough explanation of this distinction, read Sound Absorption Versus Soundproofing on the BASWA acoustical plaster resource pages.
Yes. BASWA finishes that are trowel-applied smoothly function as high-quality projection surfaces due to the system's light reflectance value of 0.91 per ASTM E1477-98. Notable projection installations include multiple planetariums, museums, and the New World Symphony Hall in Miami. Contact BASWA to discuss projection requirements for your specific project.
BASWA offers a range of hand-applied and spray-applied marble aggregate finishes. The primary distinction between finishes is the size of the marble aggregate used, which affects surface texture and the degree of smoothness achievable. Classic Fine and Fine use the finest aggregate (0.5mm) and are ideal for spaces with critical lighting conditions where a very smooth surface is required. Classic Base, Base, and Frost use a slightly larger aggregate and are well suited to standard commercial and residential applications. Two coat finishes are ideal for most applications and in areas with high critical lighting that demand the smoothest possible finish.
View all standard finish options or custom textures including concrete, stone, and artisanal finishes.
BASWA Phon is an ideal acoustical solution for historical renovation projects. The system can be applied directly over an existing stable plaster substrate, preserving original architectural details. It can also encapsulate existing plaster that may contain hazardous materials. Decorative moulding, hand-painted motifs, and historically consistent finishes are achievable. The thin system profile, typically 30mm to 70mm, minimizes changes to room dimensions and ceiling heights.
Read more about BASWA in historical renovation applications here.
BASWA Phon Systems can be applied to walls and ceilings, and are great for flat, curved, domed, complex-curved or vaulted surfaces.
Yes. BASWA systems are engineered for high-humidity environments. Two system configurations are available: one rated for environments up to 75% relative humidity and one rated for environments up to 95% relative humidity. BASWA finishes are not water soluble, and the system achieves a score of 10 out of 10 for mold resistance per ASTM D3273. Past installations in humid environments include natatoriums, spas, porte-cocheres, and covered outdoor spaces.
Review environmental performance test data here.
BASWA Finish materials are capable of creating infinite custom aesthetics and finishes. Employing creative troweling or spray applying techniques in addition to utilizing the endlessly custom BASWA Colors tint additive or BASWA Shine materials, BASWA systems can be artistically matched to stone or concrete, or a completely unique texture. Learn more here.
BASWA Finishes can be installed over BASWA Hybrid or directly applied to drywall to allow for the fine tuning of sound within a space, absorbing the high end frequency range. This type of application is best for performance spaces with challenging high frequency regulation needs and will not affect the overall dynamism of the performance. Third party acoustical test data for BASWA Hybrid available upon request.
BASWA acoustic does not believe owners and designers should be limited in choices of finish colors. BASWA Systems can be finished to match any color or multiple color gradients, tying the finished surfaces into the overall design aesthetic of the space. In no way does the tint affect the acoustical absorption qualities, as these colors are integrally added to the product before application.
If a mural or decorative accent painting is desired, care must be taken to select a paint that is not likely to bridge pores, such as a water based paint. Acoustical ceilings perform through the porosity of their surface and lose their acoustical absorption when painted with traditional paints.
Contact BASWA acoustic to find out more about color and how you can start planning your new finish.
The cost of a BASWA acoustical plaster system varies based on project size, system thickness, finish selection, location, and installation complexity. BASWA acoustic provides budget information on request and works directly with architects, owners, and contractors to provide accurate project-specific pricing. Contact BASWA for budget-level guidance early in the design process to support project feasibility and specification decisions.
For pricing of any BASWA acoustical plaster system, please contact BASWA acoustic.
All technical data for BASWA Phon is available here. If you are in need of specific details or submittal information, please contact BASWA acoustic.
BASWA is uniquely mindful of sustainability from product development, raw material sourcing, and manufacturing impact, to the end-user's wellbeing. BASWA strives to standardize wellbeing in all spaces. #HealthyArchitecture
BASWA systems are VOC-free, Formaldehyde-free, have no LBC Red List violations, high light reflectance and R-values, are 81 - 83% recycled content, and EPD & HPD documented. More information on how BASWA integrates into LEED or Well certified projects is available here.
Yes. BASWA acoustic has extensive experience working with project teams of all configurations, including architects, interior designers, acoustical engineers, general contractors, and owners. BASWA provides direct technical support, specification assistance, and LEED or WELL documentation to any member of a project team. Learn more about BASWA's engagement with acoustical engineers and design professionals, or contact BASWA acoustic to discuss your project.
BASWA systems are unique in many ways. BASWA acoustic pioneered the seamless acoustical system market, and has set the standard for performance and aesthetics.
BASWA Systems are not just an acoustical panel or finish with added, disparate, off-the-shelf components, but a complete and fully-tested system that creates a monolithic aesthetic.
BASWA offers the following qualities:
BASWA Phon and other BASWA systems are available globally through a network of certified independent installers. Installers are trained and certified directly by BASWA acoustic to ensure consistent quality of installation. Learn more about the certified installer network or find your local certified contractor.
BASWA Systems are installed in a wide variety of project types, from Yale University to the White House, Utah Museum of Natural History to Dallas Cowboys Stadium, and Carnegie Hall to private residences or restaurants. A portfolio of projects that have incorporated BASWA Systems is available here.
The beauty of a finish is just as important as the acoustic performance qualities. Where some seamless acoustic products may come as a formaldehyde-based, soft, puncturable, or have short-lifespans, BASWA Systems create a durable, smooth surface developed for longevity. BASWA Phon follows the contours of a substrate, curving across domes or across arched ceilings and creates an elegant and effective environment for events, get-togethers and general purpose rooms. In addition to these qualities, BASWA Systems have the following advantages:
Yes. BASWA Phon and BASWA Natural are uniquely suited to non-planar surfaces including curved walls, domed ceilings, groin vaults, barrel vaults, and compound-curved surfaces. Panels are installed down to a 2-foot radius curve. For tighter or more complex curves, panels are factory-kerfed on the back face to increase flexibility and conform to the required geometry. Mechanical fasteners used during curing are removed after the adhesive sets and the holes are filled with BASWA Fill which ensures a seamless finished surface with no telegraphing of fasteners.
The BASWA Phon Seamless Sound Absorbing Plaster System is used to reduce reverberation time making voice, music and other sound much more intelligible. The full engineered system is made up of a Supporting Panel of mineral fiber adhered to a stable substrate, such as drywall, and seamlessly coated with a micro-porous marble coating. Learn more here.
BASWA systems are typically installed at the same point in the construction schedule as lay-in ceiling tiles. The following conditions must be met before installation begins:
• Proper substrate is installed and taped to Level 1.
• All substrate penetrations are sealed with drywall mud, tape, or adhesive-backed tape.
• Drywall abutting the application area is primed at minimum.
• Required scaffold is fully assembled.
• Electrical power is available on-site.
• The installation area is conditioned to appropriate temperature and humidity.
A typical installation takes 4 to 5 days from panel installation through final finish coat. Contact BASWA acoustic early in the project schedule to plan installation sequencing.
Trimless access panels up to 8’x 8’ are available. Contact BASWA acoustic to discuss your access panel needs.
BASWA Phon systems are installed over a new or existing, stable, sealed substrate. Ideal substrates include standard drywall with taped joints (no finished coating of the tape or screw heads required), concrete, intact existing plaster, or GFRG forms. Due to the system’s lightweight construction, ceiling substrate system does not typically require additional or unusual support.
HVAC diffusers, fire sprinkler heads and light fixtures are roughed in below gypsum board to finished ceiling height. Voids and penetrations not yet sealed with drywall tape are sealed with adhesive tape. This creates sealed substrates that do not allow air to pass through which would otherwise cause discoloration over time. Learn more about the installation of BASWA Systems here.
Yes. All BASWA systems are designed to integrate with all standard ceiling components including recessed lighting, HVAC diffusers, fire sprinkler heads, concealed speakers, and access panels. These elements are rough-in at finished ceiling height before BASWA panel installation, and all cut-outs are made on-site to ensure precise fitting. Concealed speakers can be recessed directly into the BASWA panel, meshed, and finish-coated to create an acoustically transparent, invisible speaker installation. Trimless access panels up to 8 feet by 8 feet are available.
Learn more about installation coordination here.
BASWA acoustic has a global network of certified installers. For a list of approved and certified BASWA Phon Installers, contact BASWA acoustic.
BASWA Phon is installed exclusively by BASWA Certified Installers, independent contractors who have been trained and certified by BASWA acoustic. Certification ensures consistent system performance and finish quality. New companies may pursue certification through BASWA acoustic's technical sales department. BASWA provides on-site training at the time of certification and ongoing technical support throughout every project. This network is supported by a contractor-dedicated technical team and continuous education program.
Learn more about the certified installer program or contact BASWA acoustic to find a certified installer near you.
Every project differs in technical installation details. A typical installation takes 4-5 days. Typical drying time between coats is overnight.
Yes. BASWA systems can be repaired using techniques similar to drywall repair. Damaged panel sections can be replaced and refinished to match the existing surface. Because BASWA finishes are available in any custom color and the finish material is a consistent batch product, color matching of repairs is achievable. BASWA's technical team and certified installers are trained in repair procedures.
Read repair and patching guidelines here.
BASWA system panels are not easily compressible, with system options specifically engineered to increase impact-resistance in areas that demand it. The marble aggregate finish is highly durable and puncture-resistant compared to other acoustical finishes. The system is significantly more durable than cellulose-based finishes or soft, easily punctured produucts. BASWA surfaces can be damaged by significant physical impact but these conditions are uncommon in properly maintained interior spaces.
Request a physical sample to evaluate the finish durability directly.
BASWA has developed a full line of products that are intended to extend the life of a BASWA System, in line with the goal of offering the most sustainable systems. The products range from prevention of damage to cleaning, to refreshing a finish. Learn more about these products here or watch them in action here.
Warranties are available for BASWA system installations. Coverage terms are project-specific. Contact BASWA acoustic to discuss warranty terms for your project.
Color change options are available for existing BASWA installations. The specific approach depends on the current installation condition and the desired result. Contact BASWA acoustic to discuss refinishing options.
Standard household cleaning products and conventional paint should not be used on BASWA acoustical plaster surfaces because they can bridge the microscopic pores that make the system acoustically absorptive, permanently degrading performance. BASWA has developed a purpose-formulated product line for cleaning and maintenance: BASWA Clean for surface cleaning, BASWA Protect for repelling water and dirt before they become embedded in the surface, and BASWA Fresh for refinishing. These products are specifically formulated to refresh the surface without closing its pores.
If staining is significant, BASWA acoustic's technical team can evaluate the condition and recommend the appropriate approach, which may include surface cleaning, localized refinishing, or application of BASWA Protect to prevent recurrence. Contact BASWA acoustic directly to discuss any maintenance situation.
View the BASWA maintenance product line and contact BASWA acoustic for guidance.
