Product Overview
Everbuild AC95 Intumescent Fire & Acoustic Sealant & Adhesive supplied in a 900ml cartridge. This is a high-strength, permanently flexible intumescent acrylic compound designed for sealing and bonding plasterboard and kraft-lined insulation boards in fire-rated and acoustic-controlled environments.
It combines the performance of a sealant and adhesive, forming a dense, resilient barrier that expands under fire exposure to maintain compartment integrity.
Water-based and solvent-free, it is simple to apply, non-flammable, and easily cleaned with water during use. It achieves up to five hours of fire resistance when tested to EN1366-4:2006, offering a 25% performance increase over standard fire-rated sealants.
Once cured, it remains flexible and resistant to cracking, ensuring long-term acoustic and thermal stability in joint and panel systems.
With a density of approximately 1.6 – 1.65 g/cm³ and a Shore A hardness of around 40, AC95 provides a stable, smooth seal with low slump characteristics, even on vertical joints.
It performs reliably between –15 °C and +70 °C and maintains its integrity across a range of building materials including plasterboard, timber, metal, and blockwork.
Designed for professional fire-stopping, acoustic isolation, and adhesive bonding applications, Everbuild AC95 offers high grab, mould resistance, and a consistent finish that supports both performance and aesthetic continuity in building interiors.
The cartridge format provides a 900ml working volume.
Features & Benefits
- High fire resistance: Provides up to 5 hours of fire-rated sealing performance when tested to EN1366-4:2006.
- Acoustic barrier: Seals joints to minimise sound transmission between plasterboard walls, ceilings, and floors.
- Dual-purpose formulation: Functions as both an intumescent sealant and a strong bonding adhesive for plasterboard and insulation panels.
- Permanent flexibility: Retains elasticity to accommodate minor movement and prevent cracking.
- Water-based and solvent-free: Safe, non-flammable, and easy to clean up with water.
- Excellent adhesion: Bonds to plasterboard, timber, metal, and blockwork without the need for primers on most substrates.
- Mould resistant: Maintains a clean, durable finish in long-term installations.
- Low slump performance: No slumping in vertical joints up to 20 mm × 10 mm at 25 °C.
- Temperature range: Suitable for application between +5 °C and +40 °C; serviceable from –15 °C to +70 °C.
- Cartridge size: 900ml capacity for large-area sealing and bonding applications.
Applications
- Plasterboard sealing: Forms an intumescent and acoustic barrier at board joints and perimeters.
- Panel bonding: Bonds plasterboard to plasterboard, timber, metal studding, or blockwork.
- Insulation fixing: Adheres kraft-lined insulation boards in dry-lining systems.
- Fire stopping: Seals service penetrations and linear joints to maintain fire compartment performance.
- Acoustic isolation: Reduces airborne sound transmission in partition and ceiling interfaces.
Installation Guidance
- Surface preparation: Ensure surfaces are clean, dry, and free from dust or loose material; prime new plaster with diluted Everbuild 501 PVA Bond if required.
- Application method: Fit the 900 ml cartridge into a 1 litre mastic gun; cut nozzle to suit joint width and pierce inner seal before use.
- As a sealant: Apply a slightly overfilled bead, smooth with a caulking tool or filler knife, and remove excess with a damp cloth within 30 minutes.
- As an adhesive: Apply a continuous 9 - 10 mm bead at 250 - 350 mm centres, press boards firmly into place, and support until cured.
- Curing time: Allow 1 - 5 days for full cure depending on thickness, temperature, and humidity.
- Overpainting: Wait until the sealant is fully cured before painting - typically 24 hours, or up to 5 days in damp or cold conditions.
Compliance & Performance
- Fire rating: Tested to EN1366-4:2006 - 5 hour fire-resistant performance verified by Warrington Fire Research, Report No. 181967 (May 2009).
- Acoustic rating: Compliant with BS EN ISO 140/3 for sound insulation.
- Ventilation test: Conforms to EN13141-1 for air permeability.
- Joint compound classification: EN13963 Type 4a.
- Sealant standard: EN15651-1:2012 Type F-INT for interior fire-resistant applications.
- Chemical base: Ready-to-use, thixotropic, water-borne acrylic formulation.
- Hardness and density: Shore A ≈ 40; density ≈ 1.6 – 1.65 g/cm³.
- Movement capability: ± 5 % with low slump behaviour.
- Storage: Keep in cool, dry conditions; protect from frost. Shelf life 12 months.
- Important note: Do not use in contact with bituminous materials or cPVC piping; always ensure adequate ventilation during curing and follow fire-stopping regulations.