Rockwool Panel Specification & Installation Guide
Rockwool (stone wool) sandwich panels are the primary structural wall and roof cladding choice for industrial buildings requiring zero-flame-spread safety, acoustic dampening, and high thermal stability. Engineered from basalt rock melted at 1500°C and spun into high-density fibrous slabs, these composite panels deliver up to 4 hours of certified fire resistance (EI 240) while maintaining non-combustible structural integrity.
💡 Pro Tip: Match Panel Thickness to Your Sound Insulation Target
A 50mm rockwool panel typically reduces sound transmission by 27-30 dB. If your project requires 35 dB or higher (such as compressor rooms or manufacturing floors), step up to 100mm or combine rockwool with a perforated interior skin for additional absorption.
1. How does rockwool compare to PIR and EPS for building envelopes?
Stone wool is classified as A1 non-combustible under EN 13501-1, meaning it does not contribute to fire load at any stage. PIR achieves B-s1,d0 (limited combustibility) and EPS is substantially more flammable. For projects subject to building code fire requirements, rockwool is often the only core material that meets the specification without additional fire barriers or coatings.
2. What core density do you need?
Rockwool sandwich panels typically use core densities of 100, 120, or 140 kg/m³. Higher density improves both fire resistance rating and acoustic absorption, but also increases panel weight. For most building envelope applications, 100-120 kg/m³ is sufficient. Specify 140 kg/m³ only for projects requiring EI 120 or higher fire resistance ratings.
| Technical Property |
RaxPanel Engineering Metric |
Industrial Benefit |
| Rockwool Core Density |
100 kg/m³ to 140 kg/m³ (Specialized up to 160 kg/m³) |
Prevents internal core sagging and supports high wind loads |
| Fire Resistance Class |
EN 13501-1 Class A1 / ASTM E136 Non-Combustible |
EI 30 to EI 240 fire boundary insulation |
| Thermal Conductivity (λ) |
0.038 W/m·K – 0.044 W/m·K |
Stable thermal insulation across extreme temperature ranges |
| Acoustic Damping (Rw) |
30 dB – 34 dB (Up to 42 dB with perforated skin) |
Absorbs heavy industrial machinery noise and reverberation |
3. What steel facing options are available?
Standard facings are pre-painted galvanized steel (PPGI) and aluminum-zinc coated steel (AZ150), from 0.4mm to 0.8mm thickness. For exterior walls and roofs exposed to UV and acid rain, PVDF coating is recommended. Polyester (PE) coating is sufficient for interior partitions where weather exposure is not a concern.
4. How do rockwool panels handle moisture?
🛡️ Moisture Protection:
- Water Repellency: Stone wool fibers are treated with hydrophobic additives during manufacture to keep water absorption low even under prolonged rain exposure.
- Vapor Permeability: The fiber matrix is breathable, allowing internal humidity to escape rather than trapping condensation inside the panel cavity.
5. Where are rockwool panels commonly used?
🏭 Industrial & Warehouse Buildings
Fire-rated external walls and roofs for factories, logistics centers, chemical plants, and power stations.
🔊 Acoustic Enclosures & Commercial Buildings
Sound-absorbing walls for equipment rooms, generator enclosures, and commercial partition walls.
6. How are rockwool panels installed?
Rockwool wall panels use concealed-fix tongue-and-groove joints. Screws are driven into the joint recess before the next panel slides into place, keeping all fasteners hidden from view. This speeds up installation and eliminates exposed screw heads that could become a source of water ingress over time.
Frequently Asked Questions (FAQS)
1. What is the minimum order quantity (MOQ)?
For standard specifications (1000mm width, common thicknesses and colors), the MOQ is typically one 20ft container. For custom widths, colors, or non-standard thicknesses, a higher MOQ may apply. Contact us with your specification for an exact minimum.
2. Does mineral rockwool absorb water during heavy rain exposure?
No. The stone wool fibers are treated with hydrophobic additives during manufacture, so water absorption remains very low even under prolonged rain exposure. The exact water absorption value is listed in the data sheet above.
3. What is the typical production lead time?
For standard specifications, production typically takes 10-15 working days after deposit confirmation. Custom colors, special widths, or large-volume orders may require 20-30 days. We will confirm an exact schedule when you place your order.
4. What accessories are included with the panels?
Standard accessories include corner flashings, U-channel tracks, Z-flashings, and EPDM sealing gaskets. Fixing screws and weather sealant are also available. Let us know your project details and we will provide an accessory list matched to your panel specification.
5. Can I order custom colors and surface finishes?
Yes. We offer RAL color matching for both polyester (PE) and PVDF coatings. Common stock colors include white, grey, and blue. For custom colors, a minimum quantity applies and a color sample will be provided for approval before production.
6. Are rockwool sandwich panels suitable for food processing or cleanroom facilities?
Yes, when configured with smooth food-safe PVC or stainless steel inner skins and sealed tongue-and-groove joint gaskets, providing non-combustible cleanroom firewalls.
7. How are long rockwool panels protected against sagging during sea container transit?
Panels are wrapped in heavy-duty PE film, stacked with foam protection blocks, and strapped into rigid wooden export crates to prevent bending or core compression during ocean freight.
