Everbuild AC95 Intumescent Fire & Acoustic Sealant & Adhesive 900ml

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.