ROCKWOOL MINERAL WOOL FACADE BOARDS

Rockwool mineral wool facade boards referred as Dual Density Slabs are particularly, breathable insulation boards composed of mineral wool, to be perfect insulators for external wall insulation with all kinds of finish coatings. Unlike fibreglass, Rockwool is made from molten volcanic rocks. Boards are completely non-combustible achieving a Euroclass rating of A1 for non-combustibility – highest rating that an insulation material can have. This means that it doesn’t burn and won’t contribute to any stage of a fire. The Dual Density slab has a resilient surface for accepting mushroom-head fixings (highly compressed), whilst the underside absorbs any imperfections or unevenness in the substrate. The fibres of adjacent slabs knit together when tightly butt jointed, eliminating any gaps through which heat can be lost. Mineral wool is a heavier insulation material, it requires metal insulation fixings which are a lot stronger than plastic, which come with a plastic outer casing to help prevent thermal bridging. 

Alongside the excellent sound absorption properties offered by ROCKWOOL stone wool, the change in density between the two layers provides an additional benefit in that it causes soundwaves to be reflected at the interface, further enhancing the acoustic performance. Because of the greater weight of Mineral Wool, it is advised to you use either Ceresit CT87 or EWI-225 Premium Basecoat for the application rather than a standard adhesive, which is used on lighter insulating materials such as Grey Polystyrene or Kingspan K5 Phenolic Insulation boards. EWI systems incorporating ROCKWOOL slabs can add significant mass to the building envelope, helping to limit the transfer of sound and vibration, while the fibrous nature of the product also helps to stop sound through absorption. Slabs are dimensionally stable and won’t shrink or degrade over the lifetime of the building. 

The breathable open-cell structure of ROCKWOOL stone wool allows water vapour to pass through, while the randomly oriented water-repellent fibres work to prevent water ingress. Due to its excellent lambda value (0.036 W/mK), the board achieves a 15% better U-value for the external wall, as if we were using the same insulation thickness of the standard EPS polystyrene board. Moreover, it is more breathable material compared with EPS. It provides superior fire resistance properties without fire stops requirements. It has a higher R-value per inch compared to fiberglass (about a 22-37% higher R-value). It contains 70% recycled material, making it a greener product than fiberglass at 20-30% recycled material. ROCKWOOL stone wool products are also resistant to termites.

ROCKWOOL DD MINERAL WOOL SIZES

Depending on the application ROCKWOOL can make a board product up to 200mm. Rockwool slabs are being produced in two dimensions. Either in 1200mm x 600mm called Dual Density (made in the UK) or 1000mm x 600mm named Frontrock Super/Max E/Plus (sold mainly in Europe). While Dual Density comes in thicknesses: 30mm, 50mm, 70mm, 80mm, 90mm, 100mm, 110mm, 120mm, 150mm and 200mm, Frontrock Max E goes extra mile and offer readily available product thicknesses such as 140mm, 160mm and 180mm. No matter which name is used, the 30mm and 50mm size is the most popular thickness used in external wall insulation as of Rockwool mineral slab range. Both have a thermal conductivity of 0.035 W/mK.

KEY CONSIDERATIONS FOR ROCKWOOL DD INSULATION ON EXTERNAL WALLS

Isolating external walls with Rockwool DD dual-layer insulation requires special attention to ensure effective soundproofing, insulation, and fire protection. Proper installation is crucial, and particular consideration should be given to the following:

 Protection from Rain - the Rockwool insulation should not be exposed to rain during installation.

 Precise Fastening and Alignment - pay attention to the accurate fastening of slabs and ensure proper alignment. 

 Appropriate Render Type - use the correct type of render to allow the Rockwool to breathe. This ensures proper ventilation and moisture management.

 Fixings with Metal Pins - due to the hardness of the slabs, consider using fixings with petal pins for secure attachment.

 Maximum Render Thickness - do not apply a render coat thicker than 5mm, as thicker coats may lead to cracking.

 Extended Installation Time - note that Rockwool boards may require more precision during installation compared to grey polystyrene, and the installation process may take longer.

 Surface Preparation - ensure that the substrate to which the Rockwool is adhered is dry, free from dust, and contaminants. 
 

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