Innovative Uses of Soundproof Plasterboard in Ceilings and Floors

Modern acoustic insulation goes far beyond wall assemblies. Builders and designers are leveraging the sound dampening properties of specialised plasterboard systems for ceilings and floors. For this feature, we examine the possibilities soundproof plasterboard offers for these applications.

Is soundproof plasterboard suitable for flooring?

Primarily used for wall and acoustic plasterboard ceiling projects, it can also be installed into floor systems. Specialised flooring underlayment panels made from dense gypsum core materials are designed specifically for sound isolation between floors. These panels offer several key benefits when used in flooring applications. 

• High mass combined with viscoelastic damping compounds like acoustic sealant and mass-loaded vinyl (MLV) to block impact and airborne noise transfer. 
• Tongue-and-groove edges create airtight seams when joined for enhanced sound mitigation.
• Can be used as part of engineered floor assemblies with added components like resilient channels. 
• Enable floating floor system designs using spring isolators for independent, suspended operation.
• Provide an effective and durable solution for blocking noise between vertically stacked floors.

How thick is the ceiling and floor soundproof plasterboard?

Plasterboard thickness is a critical factor that impacts the ability to block noise transmission through ceilings and floors. Using the proper thickness helps ensure optimal sound isolation performance. Below are some general guidelines to consider.

Ceiling applications

• 15.9mm (5/8") thickness is generally the minimum recommended for basic ceiling applications to reduce sound transfer between floors.
• 25mm (1") or 32mm (1.25") thicknesses provide significantly better sound blocking for ceilings. This is especially true for higher sound transmission class (STC) ratings above 55-60.
• Doubling panels with a 15.9mm base layer and 12.7mm (1/2") top layer boosts ceiling STC performance.

Potential issues: If using panels thinner than 15.9mm for a ceiling, the sound will have an easier path to flank through. Sound will also transmit between floors, degrading the acoustic isolation. This is especially problematic with household noises like TVs and music. 

Floor applications

• 6mm (1/4") underlayment is the minimum recommended thickness. However, it is only suitable for basic floor applications with light noise sources.
• 12.7mm (1/2") offers better impact insulation performance for most floor installations.
• For high-impact areas, 19mm (3/4") or 25mm (1") underlayment panels offer superior impact and airborne noise control.

Potential issues: Floor underlayments thinner than 12.7mm may allow too much impact noise like footsteps to transmit through. This creates sound disturbances in the rooms below. Insufficient noise insulation plasterboard thickness also reduces the overall mass, preventing the system's resistance to block airborne noises.

Additional tips

• Pair thick soundproof plasterboard with sound-blocking materials. For example, mass-loaded vinyl, resilient channels or fibreglass insulation will complete the assembly. 
• Make sure to follow all manufacturer installation instructions and account for proper compression allowance. 
• Look for STC rate options for different panel thicknesses to select the one best suited for your sound isolation needs.

6 creative applications for plasterboard soundproofing

Soundproof plasterboard systems are effective at blocking noise transfer and their versatility allows for creative applications beyond sound isolation. It is possible to leverage sound insulation plasterboard in innovative ways to precisely tailor acoustic levels.

1. Home theatres/media rooms

Installing soundproof plasterboard into double-framed ceilings and floating floors provides low-frequency sound isolation between the home theatre and surrounding rooms. This prevents audio bleed (spill) and contains bass vibrations within the space.

2. Recording studio floors

A floated floor separated from walls and built with staggered layers of dense acoustic board and concrete toppings creates a solid surface. It minimises structural vibrations and noise bleed. This allows for cleaner audio recordings by preventing acoustics from becoming distorted because of ambient noises entering the studio. 

3. Exercise and dance studios

Absorbing impacts from dropped exercise balls and dancing requires durable, high-performance flooring. Pairing a soundproof plasterboard underlayment with shock-absorbing materials like channels and MLV achieves privacy and a cushioned surface. 

4. Commercial office ceilings

Suspending acoustic ceiling plasterboard using resilient isolation clips creates a barrier that minimises ambient noise bleed between workspaces. This allows an open office layout to remain while still providing some privacy for work and conversations. It is a significant productivity booster over typical drywall ceilings.

5. Multi-purpose venues

Movable partitions made with multilayer sound insulation board materials provide improved acoustical separation compared to standard walls. This flexibility to create quiet zones or open areas allows venues to adapt for various events requiring different acoustic needs. For example, this includes corporate meetings, weddings and conventions. 

6. Healthcare settings

Meeting stringent noise criteria and reverberation time requirements is crucial in healthcare facilities for patient comfort. Soundproof plasterboard systems meet the required Approved Document E regulations and prevent privacy issues between rooms.

How to tackle sound plasterboard challenges

There are some unique challenges to address during installation. Being aware of these potential issues allows you to plan accordingly and ensure an effective, high-quality soundproofing plasterboard structure. 

Airtight seals and flanking paths

Even tiny air gaps or cracks create flanking paths that allow sound to travel through ceiling and floor assemblies. The sound can bypass the soundproofing barrier. Flanking occurs when noise takes an indirect path through any unsealed holes or seams rather than being blocked by plasterboard panels.

Solution: Pay close attention to creating airtight seals when joining panels and blocking all potential flanking paths. Use acoustical sealant along joint, edge and penetration areas. Stagger panel joints and seams so they do not line up between adjacent rooms. Properly seal electrical boxes, ductwork and piping with non-hardening acoustical caulk.

Adding mass topically

The greater the mass and density of a ceiling or floor system, the more effective it will be at blocking sound transmission. While acoustic insulation plasterboard provides decent mass, there are ways to boost it by adding mass elements over the panels. However, this added weight needs to be properly accounted for.

Solution: Consider adding a dry or wet topping over the soundproof plasterboard underlayment. For example, you can add lightweight concrete, self-levelling underlayment or MLV. Make sure to account for compression allowance if using resilient channels. 

Creating a double-framed wall

Without an independent framing separated from adjacent wall studs, vibrations can travel through direct structural connections bypassing the soundproofing barrier. It affects the noise-blocking benefits of the dense plasterboard panels.

Solution: For the best sound isolation, use a double-framed wall design where the ceiling or floor framing is completely decoupled from adjacent wall framing to prevent sound bridging. Use resilient sound isolation clips to suspend 1 frame from the other.

HVAC and plumbing noise flanking

Components like HVAC ductwork, plumbing pipes and electrical conduits allow noise to travel if they are not properly decoupled from ceiling and floor cavities. Vibrations can transmit directly through these elements, bypassing soundproofing barriers.

Solution: Make sure to use resilient sound-absorbing hangers and gaskets to prevent vibrations from transmitting to the framing. Also, wrap ductwork and piping with insulation jackets.

Footfall and impact noise

Impact noises from footsteps and dropped objects require different measures than airborne noise mitigation. The force of impact creates vibrations that need to be absorbed through the flooring system before transmitting into the spaces below.

Solution: For areas with heavy foot traffic, install a fully floating floor system using rubber isolators or spring hangers. This creates an independent upper floor suspended within the framed cavity. Top with soundproof plasterboards and soft, dense surface flooring.

Cracks from floor deflection

Over time, excessive bounciness in subfloors and joists can cause the soundproof plasterboard underlayment to develop cracks. This compromises the structural integrity of the system and creates potential sound leakage paths.

Solution: Reinforce the subfloor to prevent excessive deflection. To do this, you can use construction adhesive and fasten into floor joists. Also, additional support like extra joists can help stiffen an overly bouncy subfloor. 

Does soundproof plasterboard for floors and ceilings last?

When properly installed and maintained, soundproof plasterboard provides excellent acoustic performance for many years in both ceiling and floor applications. However, some key factors impact their overall longevity.

• Manufacturing quality - Higher density gypsum cores and composite materials in boards resist deterioration better over time.
• Humidity/moisture exposure - Excessive moisture may cause swelling, delamination and loss of structural integrity if not properly sealed.
• Physical impacts or vibrations - Ceilings and floors are more susceptible to damage from roof leaks, deflection, dropped objects, etc. compared to wall assemblies.
• UV exposure - Direct sunlight can degrade exposed plasterboard surfaces over extended periods.
• Maintenance and repair issues - Leaving cracks, holes or other damage unrepaired creates failure points.

For ceiling applications with minimal moisture risk, soundproof plasterboard is expected to last 30+ years. Proper sealing and avoiding excessive weight loads is important. With floor applications, the lifespan may be shorter at around 20-25 years depending on foot traffic levels and potential impacts.

Generally, soundproof plasterboard floors tend to have a higher risk of deterioration compared to acoustic boards for walls and ceilings. This is because of increased exposure to impacts, moisture from surface spills and structural movements.