Rockwool 120mm High Performance Partial Fill Cavity Slab

The 120mm Rockwool High Performance Partial Fill Cavity Slab delivers a semi-rigid insulation solution engineered for masonry cavity wall construction.

Achieving a Euroclass A1 rating, this 120mm Rockwool partial fill cavity slab combines thermal performance with straightforward installation. The dual-density design accommodates irregularities on the inner leaf whilst providing a robust outer surface for retaining clip attachment. This construction method protects external walls from thermal loss, maintaining energy efficiency and eliminating gaps that compromise insulation integrity.

Product specification

• Thickness: 120mm
• Length: 1200mm
• Width: 455mm
• Board Coverage: 0.546
• Pack Coverage: 2.78 m2
• Pack Quantity: 6
• Thermal Conductivity: 0.034 W/mK
• Application: Cavity Wall Insulation
• Features: Fire Protection
• Fire Protection: Non-Combustible
• Material: Mineral Wool
• Application: Masonry and framed cavity wall construction
• Product standards: BS EN 13162
• CE Marking: CE Marked
• BBA Approved: Certificate 93/2884
• Water repellent: Yes
• Water vapour resistance: Negligible

Features & Benefits: ROCKWOOL Partial Fill Cavity Slab 120mm

• Designed for masonry and framed cavity wall applications, including tall residential and commercial buildings.
• Non-combustible classification with Euroclass A1 rating delivers exceptional fire safety performance.
• Boosts thermal efficiency, supporting improved energy performance standards.
• Water-resistant with a reinforced facing to withstand site conditions and maintain durability.
• Interlocking slab design seals cavities effectively, reducing thermal bridging and heat escape.
• Semi-rigid 120mm partial fill insulation format enables quick, reliable installation.
• Dimensions: 1200mm length x 455mm width x 120mm thickness.
• Coverage of 27.3m² per pallet.
• Thermal conductivity of 0.34 W/mK delivers consistent insulation performance.
• Performs across all exposure zones with a minimum residual cavity width of 120mm. In severe exposure locations, external render finishes or equivalent protection may be required, in line with building practice standards.

Applications

Buildings up to and including 12 metres:

• The product performs in any exposure zone where a residual cavity width of 120mm or greater is preserved. External render coats or comparable finishes remain necessary in severe exposure zones where standard practice dictates their use.
• During construction, maintain a minimum residual cavity width of 25mm. Greater nominal cavity widths may be specified at design stage to account for typical building tolerances. The NHBC, for example, recommends a nominal residual cavity width of 80mm under standard tolerance and workmanship conditions.

Buildings over 12 metres in height: For buildings exceeding 12 metres, achieve a minimum residual clear cavity width of 120mm with these requirements:

• Continuous cavity walls from ground level must not exceed 12 metres.
• Above 12 metres, continuous cavity walls should not surpass 7 metres.
• Continuous horizontal cavity trays discharging externally are required in both cases.
• Where cavity width reduces for structural purposes, such as ring beam intrusion, maintain a minimum residual cavity width of 25mm. Additional care with fixings and weatherproofing, including cavity trays, is essential.

Benefits

120mm Rockwool Partial Fill Cavity Insulation provides a reliable, long-lasting solution for thermal insulation of external walls.

Like stone, 120mm Rockwool Partial Fill Cavity stone wool insulation delivers inherent durability. With a proven lifespan of 65 years and beyond, performance remains consistent regardless of weather, moisture, temperature fluctuations or compression—requiring no maintenance or specialist intervention.

More Information on 120mm Partial Fill Cavity Slab

• Manufacturer Link: Rockwool Twin Roll
• 120mm Rockwool Partial Fill Cavity Slab represents high-performance insulation with diverse application possibilities.
• Browse our full Rockwool Insulation range and refine by thickness or coverage using the filters. For project-specific advice or bulk pricing enquiries, contact us by phone on +4402038839057, email sales@insulationbee or use Live Chat - Competitive UK Rockwool Insulation Pricing.