Rock Mineral Wool Insulation Isover Fasoterm 50mm/4,8m²

Isover Fasoterm 35 – Premium Rock Wool Insulation Board for External Wall Insulation Systems (ETICS)

Isover Fasoterm 35 is a high-performance stone mineral wool insulation board specifically designed for external wall thermal insulation using the ETICS (External Thermal Insulation Composite System) method. Manufactured by Saint-Gobain, one of the world’s leading building materials producers, Fasoterm 35 delivers outstanding thermal performance, exceptional fire safety, and excellent moisture management for both new-build and renovation projects.

Each pack covers 4.8 m² and contains boards sized 1000 x 600 mm at 50 mm thickness. The hydrophobized mineral fibre construction ensures minimal water absorption while maintaining full vapour permeability, allowing building walls to breathe naturally and preventing moisture build-up within the wall structure.

Isover Fasoterm 35 is the preferred choice for projects where fire safety is a critical requirement, as mineral wool achieves Euroclass A1 (non-combustible) rating — the highest fire classification available. This makes it ideal for high-rise buildings, public buildings, and all applications where non-combustible insulation is required by building regulations.

Key Features

• Euroclass A1 non-combustible – the highest fire safety classification
• Thermal conductivity λD = 0.035 W/mK – excellent thermal efficiency
• Thermal resistance RD = 1.40 m²K/W at 50 mm thickness
• Hydrophobized surface – short-term water absorption ≤ 1 kg/m²
• Fully vapour permeable (μ = 1) – allows walls to breathe
• Tensile strength perpendicular to faces ≥ 10 kPa (TR10)
• Compressive stress at 10% deformation ≥ 20 kPa
• Excellent sound insulation properties
• Dimensionally stable under temperature and humidity changes
• Compatible with all standard ETICS adhesives and renders

Technical Specifications

Applications

Isover Fasoterm 35 is designed for use in ETICS external wall insulation systems. It is suitable for application on:

• Concrete walls and panels
• Masonry walls (brick, block, stone)
• Cement and cement-lime rendered surfaces
• Timber frame constructions (with appropriate detailing)
• Steel frame buildings

Mineral wool insulation is particularly recommended for buildings where non-combustible materials are required, including multi-storey residential buildings, commercial premises, schools, hospitals, and public buildings.

Instructions for Use

1. Surface preparation: The substrate must be clean, dry, load-bearing, and free from dust, loose paint, or other contaminants. Apply a suitable primer if required.
2. Adhesive application: Apply ETICS-approved adhesive mortar using the perimeter-and-dab method or full-bed method with a notched trowel. The adhesive should cover a minimum of 40–60% of the board surface.
3. Board installation: Press boards firmly onto the prepared substrate in a staggered brick-bond pattern. Ensure tight butt joints between boards with no gaps.
4. Mechanical fixings: After the adhesive has set (typically 24–72 hours), secure boards with approved steel-pin mechanical fixings at a density of 6–8 fixings per m², or as specified by the system designer.
5. Reinforcement layer: Apply a layer of basecoat adhesive mortar (3–5 mm) and embed alkali-resistant fibreglass mesh into the wet mortar. Overlap mesh joints by at least 100 mm.
6. Finishing: Once the reinforcement layer has fully cured, apply a suitable primer followed by the chosen decorative render or paint finish.
7. Working temperature: Install at ambient and substrate temperatures between +5°C and +25°C. Protect freshly installed insulation from direct sunlight, rain, and frost.

Isover Fasoterm 35 combines outstanding fire safety, thermal performance, and breathability — making it the professional’s choice for mineral wool external wall insulation across the UK and Ireland.