acoustic plasterboard

Quick Answer: Noise insulation plasterboard (also called acoustic plasterboard) is a specialised board with enhanced density and sound-dampening properties that significantly reduces sound transfer between rooms. Standard acoustic boards achieve 36-46 dB sound reduction, while high-performance systems with cavity insulation can reach 55+ dB. Expect to pay £15-35 per sheet, roughly 40-80% more than standard plasterboard, but the investment dramatically improves acoustic privacy in homes, especially for party walls, bedrooms, and home offices. What Is Noise Insulation Plasterboard? Noise insulation plasterboard is a denser, heavier version of standard plasterboard specifically engineered to reduce sound transmission through walls and ceilings. Unlike regular 12.5mm plasterboard which weighs around 8kg/m², acoustic boards typically weigh 12-15kg/m² due to their increased density and often incorporate sound-dampening cores. The difference lies in both the mass and construction. Manufacturers like British Gypsum, Knauf, and Siniat add high-density gypsum cores, viscoelastic polymers, or ceramic particles that absorb and dissipate sound energy rather than allowing it to pass through. Most acoustic plasterboards comply with Building Regulations Approved Document E, which sets minimum sound insulation standards for new builds and conversions. For separating walls between dwellings, you’ll need to achieve at least 45 dB DnT,w (the weighted standardised level difference), while floors require 45 dB airborne and impact sound insulation. How Does Acoustic Plasterboard Work? Sound travels as vibrations through air and solid materials. When sound waves hit a wall, they cause it to vibrate, transmitting noise to the other side. Acoustic plasterboard works through three primary mechanisms: Mass: Heavier materials are harder to vibrate, so increased density reduces sound transmission Damping: Viscoelastic layers within the board convert sound energy into small amounts of heat Decoupling: When used with resilient channels or independent stud frames, it prevents vibrations transferring directly through the structure The most effective acoustic solutions combine acoustic plasterboard with cavity insulation (mineral wool or acoustic foam) and proper installation techniques. A single layer of acoustic board alone offers modest improvement, but a complete system can reduce sound transfer by 50-60 dB. Pro Tip: Sound insulation works differently from thermal insulation. Thermal insulation is light and fluffy (trapping air), while acoustic insulation needs mass and density. Don’t assume your insulated walls are automatically soundproofed — they’re solving different problems. Types of Acoustic Plasterboard Available in the UK Several manufacturers produce noise insulation plasterboard for the UK market, each with slightly different specifications and performance ratings: Product Thickness Weight Sound Reduction (Rw) Price Range British Gypsum SoundBloc 12.5mm 12.5kg/m² 36 dB £15-18/sheet Knauf Acoustic Plus 12.5mm 13kg/m² 38 dB £16-19/sheet Siniat Soundshield 15mm 15kg/m² 42 dB £22-26/sheet British Gypsum QuietPanel HD 12.5mm 14kg/m² 46 dB £28-35/sheet Standard plasterboard sheets (2400mm x 1200mm) cost £8-12 at Wickes or Screwfix, so acoustic boards represent a 40-80% premium. However, for critical applications like party walls, recording studios, or home cinemas, the cost is justified by the significant noise reduction. You can also find moisture-resistant acoustic boards for bathrooms and kitchens, combining the properties of both waterproof plasterboard and sound insulation, though these typically cost £35-45 per sheet. Installation Methods for Maximum Sound Reduction Simply swapping standard plasterboard for acoustic board won’t give you the full noise reduction potential. Installation technique matters enormously. Here are the key methods: Single Layer Application The most basic upgrade involves replacing standard plasterboard with acoustic board during drywall installation. This provides modest improvement (5-8 dB reduction) and works well for: Internal partition walls in new builds Bedroom walls where moderate privacy is needed Office spaces requiring basic speech privacy Install exactly like standard plasterboard using 32mm drywall screws at 200mm centres vertically and 300mm centres horizontally. Always fix to the timber or metal studs, never to the board edges alone. Double Layer Systems For significantly better performance, use two layers of plasterboard with staggered joints. The most effective combination is: Base layer: 12.5mm standard or acoustic plasterboard fixed to studs Top layer: 12.5mm or 15mm acoustic board with joints offset by at least 600mm Adhesive: British Gypsum Gyproc Dri-Wall Adhesive between layers (not just screws) This configuration can achieve 45-50 dB reduction when combined with 100mm mineral wool cavity insulation (Rockwool RW3 or Knauf Acoustic Partition Roll at £15-20 per pack from Travis Perkins). Resilient Bar Systems The gold standard for sound insulation involves acoustic resilient bars (also called furring channels). These metal channels are fixed horizontally to studs at 400mm centres, with plasterboard screwed only to the bars — not directly to studs. This creates a mechanical break that prevents vibrations transferring through the frame. Combined with double-layer acoustic plasterboard and dense cavity insulation, resilient bar systems can achieve 55-62 dB reduction. ⚠️ Warning: Any penetrations through acoustic walls (electrical outlets, pipes, recessed lights) create sound leakage paths. Use acoustic sealant around all openings and avoid back-to-back sockets on opposite sides of the same wall. Even a 5mm gap can reduce your overall performance by 10-15 dB. Cavity Insulation Materials for Acoustic Walls The space between plasterboard layers or within stud walls should be filled with acoustic insulation. Not all insulation works equally well for sound: Material Density Sound Absorption Cost (100mm, 5.76m²) Mineral Wool (Rockwool RW3) 60kg/m³ Excellent £18-22 Glass Wool (Knauf Earthwool) 50kg/m³ Very Good £15-19 Standard Loft Insulation 20-30kg/m³ Poor £8-12 Acoustic Foam (Polyester) 70kg/m³ Excellent £35-45 For best results, choose high-density mineral wool (60kg/m³ minimum) specifically rated for acoustic applications. Standard loft insulation is too lightweight and springy, actually transmitting vibrations rather than absorbing them. Fill the cavity completely without compressing the insulation — compressed mineral wool loses its acoustic properties. For 100mm stud walls, use 100mm insulation. For 75mm walls, use 75mm insulation. Understanding Sound Insulation Ratings When comparing acoustic products, you’ll encounter several different measurements. Here’s what they mean in practical terms: Rw (Weighted Sound Reduction Index): Laboratory measurement of how much sound a material blocks, measured in decibels (dB). Higher is better. Rw 40 dB means the material blocks 40 dB of sound. DnT,w (Weighted Standardised Level Difference): Real-world measurement of sound insulation between rooms, accounting for room