Acoustic Insulation

Types of Acoustic Insulation

Rockwool RWA45 Acoustic Slabs

Rockwool RWA45 is the UK's most popular acoustic insulation slab, specifically designed for superior sound absorption in separating walls and floors. With 45kg/m³ density and 0.036 W/mK thermal conductivity, RWA45 delivers excellent acoustic performance alongside thermal insulation and fire protection. The semi-rigid stone wool slabs friction-fit between timber studs (400mm or 600mm centres) and floor joists without fixings, filling cavities to prevent sound resonance and reduce noise transmission between rooms and properties.

Available in 25mm, 30mm, 40mm, 50mm, 75mm, and 100mm thicknesses in 1200mm x 600mm slabs, Rockwool RWA45 achieves significant dB improvements in party wall and separating floor constructions when combined with acoustic plasterboard and resilient channels. Non-combustible with Euroclass A1 fire rating, water-repellent (won't absorb moisture), and chemically inert, RWA45 maintains performance throughout the building's lifetime. Ideal for new builds, renovations, and Building Regulations Part E compliance.

Knauf Acoustic Roll

Knauf Acoustic Roll combines acoustic performance with ECOSE Technology - a bio-based binder that eliminates formaldehyde and creates a softer, less itchy glass mineral wool. Available in 25mm, 50mm, 75mm, and 100mm thicknesses with coverage from 12.36m² to 26.64m² per roll, Knauf Acoustic Roll offers flexibility for larger installations and irregular joist or stud spacing. The roll format reduces waste compared to rigid slabs and allows continuous coverage without gaps that could compromise acoustic performance.

With 0.038 W/mK thermal conductivity and Euroclass A1 fire rating, Knauf Acoustic Roll provides soundproofing, thermal insulation, and fire protection in a single product. The pre-cut width (1200mm) can be split to 600mm for standard stud spacing, or used full-width between wider centres. Particularly effective in timber frame walls, stud partitions, suspended floors, and loft conversions where acoustic isolation is required alongside thermal performance.

Superglass Acoustic Partition Roll (APR)

Superglass Acoustic Partition Roll is a high-performance glass mineral wool roll specifically designed for acoustic applications in party walls, separating floors, and internal partitions. Available in 25mm, 50mm, 60mm, 80mm, and 100mm thicknesses, these rolls achieve higher densities than standard insulation (typically 12-14kg/m³) for superior sound absorption. The lightweight, flexible format makes installation quick and easy, with the material compressing slightly to friction-fit between studs and joists.

Superglass APR features pre-cut 600mm widths (2 x 600mm roll) for standard 400mm or 600mm stud spacing, eliminating measuring and cutting time on-site. non-combustible (Euroclass A1), moisture-resistant, and dimensionally stable, maintaining their acoustic performance throughout the building's life. Popular for apartment conversions, terraced house refurbishments, and new build properties requiring Building Regulations Part E compliance.

Knauf Rocksilk RS45 & RS60 Building Slabs

Knauf Rocksilk RS45 (45kg/m³) and RS60 (60kg/m³) building slabs offer higher density options for applications requiring maximum acoustic performance. The increased density provides greater mass for blocking sound transmission, particularly effective in party walls and separating floors where higher dB reductions are needed. Available in 25mm to 100mm thicknesses, Rocksilk slabs achieve excellent results in timber frame and masonry cavity wall constructions.

RS60 slabs are particularly popular for external walls and applications requiring both high acoustic performance and thermal insulation, with 0.034-0.035 W/mK thermal conductivity outperforming standard RWA45. The semi-rigid stone wool slabs are easy to handle, cut with a sharp knife, and friction-fit between studs without additional support. Non-combustible, water-repellent, and chemically inert, Rocksilk RS45 and RS60 are suitable for all UK climates and building types.

Where to Use Acoustic Insulation

Party Walls & Separating Walls

Party walls between terraced houses and semi-detached properties are the most common application for acoustic insulation. Building Regulations Approved Document E requires minimum 45dB airborne sound insulation (DnTw) for separating walls. Install 100mm Rockwool RWA45 or Knauf Acoustic Roll between timber studs in party wall constructions, combined with two layers of acoustic plasterboard on resilient bars for maximum sound reduction. For masonry party walls, add 50-100mm acoustic insulation within the cavity to improve acoustic performance.

Separating Floors

Floors between flats and apartments require acoustic insulation to reduce both airborne noise (conversation, TV, music) and impact noise (footsteps, furniture). Install 100mm Rockwool RWA45 between floor joists combined with acoustic underlay (Tecsound, Pliteq GenieMat) beneath the floor finish. Building Regulations require 45dB airborne sound insulation (DnTw) and 62dB impact sound insulation (L'nTw) for separating floors. The combination of between-joist mineral wool and resilient underlay achieves these requirements and creates comfortable, peaceful living spaces.

Internal Stud Partitions

Internal stud walls benefit from acoustic insulation to create privacy between bedrooms, home offices, bathrooms, and living spaces. Install 50-100mm acoustic insulation (Knauf Acoustic Roll, Superglass APR) between studs to reduce sound transmission through lightweight partition walls. Particularly effective in open-plan conversions, loft apartments, and home offices where acoustic privacy is essential. Combine with acoustic plasterboard for enhanced performance.

Suspended Timber Floors

Timber suspended floors amplify sound in the cavity beneath floorboards, transmitting noise between floors. Fill the void between joists with 100mm Rockwool RWA45 or Superglass APR to absorb airborne sound and reduce resonance. The mineral wool dampens sound waves traveling through the floor cavity, significantly improving acoustic comfort. Ideal for period properties, Victorian terraces, and buildings with traditional timber floor construction.

Benefits of Acoustic Insulation

Reduce Noise Transmission - Block airborne and impact noise between rooms and properties

Building Regulations Compliance - Meet Approved Document E requirements (45dB DnTw minimum)

Dual Thermal Benefits - Excellent thermal insulation (0.034-0.038 W/mK) alongside acoustic performance

Fire Safety - Euroclass A1 non-combustible mineral wool for maximum fire protection

Quick Friction-Fit Installation - No fixings required, slots between studs and joists

Moisture Resistant - Water-repellent stone wool and glass wool maintains performance

Improved Privacy - Create peaceful, comfortable living and working environments

Cost-Effective Soundproofing - Affordable solution for reducing unwanted noise