Rockwool 150mm High Performance Partial Fill Cavity Slab

The Rockwool 150mm High Performance Partial Fill Cavity Slab delivers a semi-rigid insulation system engineered specifically for masonry cavity wall applications.

Achieving a Euroclass A1 fire rating, this 150mm partial fill cavity slab combines thermal performance with straightforward installation. The dual-density structure accommodates surface irregularities on the inner leaf whilst providing a reinforced outer face for retaining clip attachment. This construction method protects external wall systems, maintaining long-term energy efficiency and minimising heat loss through complete insulation coverage.

Product specification

• Thickness: 150mm
• Length: 1200mm
• Width: 455mm
• Board Coverage: 0.546
• Pack Coverage: 2.18 m2
• Pack Quantity: 4
• 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 150mm Partial Fill Cavity Slab

• Perfectly suited to masonry and framed cavity wall systems, including tall residential buildings.
• Non-combustible construction with Euroclass A1 classification for exceptional fire safety performance.
• Boosts thermal efficiency, supporting improved energy ratings.
• Water-resistant finish with a protective facing to prevent deterioration and extend service life.
• Interlocking slab design eliminates gaps and reduces unwanted heat transfer.
• Semi-rigid 150mm partial fill insulation engineered for simple installation and long-term durability.
• Dimensions: 1200mm length x 455mm width x 150mm thickness.
• Coverage of 21.84m² per pallet.
• Thermal conductivity of 0.34 W/mK for reliable insulation performance.
• Suitable across all exposure zones with a minimum residual cavity width of 150mm. In severe exposure locations, external render finishes or equivalent protection may be required, in line with industry standards.

Applications

Buildings up to and including 12 metres:

• The product performs effectively in any exposure zone where a minimum residual cavity width of 150mm or greater is maintained. Note that product installation does not negate the requirement for external render or equivalent finishing in severe exposure zones where this is standard practice.
• During installation, the minimum residual cavity width must be preserved at 25mm. To achieve this, a larger nominal residual cavity width may be specified during design to account for typical construction tolerances. For example, NHBC guidance recommends a nominal residual cavity width of 80mm under normal tolerance and workmanship standards.

Buildings over 12 metres in height: For structures exceeding 12 metres, maintain a minimum residual clear cavity width of 150mm with these requirements:

• Continuous cavity walls from ground level must not exceed 12 metres in height.
• Above 12 metres, continuous cavity walls should not surpass 7 metres in height.
• Continuous horizontal cavity trays discharging externally are required in both scenarios.
• Where cavity width is reduced due to structural elements such as ring beams, maintain a minimum residual cavity width of 25mm. Additional care is needed with fixings and weatherproofing, including cavity tray installation.

Benefits

Rockwool 150mm Partial Fill Cavity Insulation provides a stable, long-lasting solution for thermal insulation in external wall construction.

Like natural stone, 150mm Rockwool Partial Fill Cavity stone wool insulation offers inherent durability. With a proven lifespan of 65 years and beyond, performance remains consistent regardless of weather, moisture, temperature fluctuations or compression – requiring no ongoing maintenance or specialist intervention.

More Information on 150mm Partial Fill Cavity Slab

• Manufacturer Link: Rockwool Twin Roll
• Rockwool 150mm Partial Fill Cavity Slab is a premium-grade product offering flexible installation options.
• Browse our complete Rockwool Insulation range and refine by thickness or coverage using the filters on the left. For technical advice on product suitability or bulk pricing requests, contact us on +4402038839057, email sales@insulationbee, or use Live Chat – Competitive UK Rockwool Insulation Pricing.