Rainscreen Duo-Slabs are intended for insulation behind rain-screen and sealed cladding systems such as curtain wall and other over-cladding constructions. With its specially designed dual density stone wool composition, the product consists of a high density, robust outer layer and a resilient inner layer to accommodate irregularities in the surface of the masonry substrate. The slabs knit together when tightly butt jointed, maximizing thermal performance and preventing water transmission through the insulation.

Designed for use in conditions of severe climatic exposure it has successfully undergone wind resistance testing by the Building Research Establishment, simulating and exceeding the maximum UK basic wind speed of 56 m/s, as defined by BS CP3: Chapter 5: Part 2: 1972. The robust, high density outer layer enables attachment to the masonry wall with just 2 fixings per slab, thus providing a cost effective insulation solution to over-cladding systems. A single stainless steel fixing is located at the centre of each slab and a second polypropylene or steel fixing shared with the adjacent slab.

The product is non-combustible, achieving a classification of A1 in accordance with BS EN 13501-1, and can therefore be used for buildings in excess of 18m in height and within 1m to the boundary, in conjunction with a Class 0 (Euroclass B-S3,d2) external cladding.

Rockwool insulation products do not contain blowing agents with an ozone depletion potential (ODP) or global warming potential (GWP), are CFC-HCFC-HFC free and 97% recyclable. They will not react with metal components or cause loss of plasticiser from PVC cables and pipes.


  • Designed for use on high rise buildings.
  • High resistance to wind and rain during construction.
  • Fewer fixings required for installation compared to standard mineral wool slabs.
  • Robust front face resists damage and over-driving of fixings.
  • Non-combustible insulation.

General information


Mineral wool




1000 x 600 mm

Uniclass 2015

Pr_25_57_06_56 Mineral wool slab insulationPrimary


H11/110 Curtain walling

H11/780 Thermal insulation

H20/10 Sheet cladding

H92/776 Thermal insulation

P10/217 Insulation slabs fixed to backing wall

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Specification data - Mineral wool slab insulation

Product Reference

Rainscreen Duo-Slab


50 mm

60 mm

75 mm

100 mm

125 mm

150 mm

180 mm

200 mm

Standard product features

Slab size:

1000 x 600 mm.

Reaction to fire class:

A1 to BS EN 13501-1.


Refer to ROCKWOOL product literature.


  • RAINSCREEN DUO SLAB® satisfies the requirements of BS EN 13162: 2012 ‘Thermal insulation products for building – Factory made mineral wool (MW) products – specification’.
  • Rated A1 when tested to EN 13501-1 classification using test data from reaction to fire test.
  • RAINSCREEN DUO SLAB® has successfully undergone wind resistance testing by the Building Research Establishment. Wind loading fatigue tests were used to simulate the performance of the slabs when fully exposed and subjected to fluctuating wind loads during the construction stages of buildings. The tests simulated and exceeded the maximum UK basic wind speed of 56 m/s as defined by BS CP3: Chapter 5: Part 2: 1972. Test report BRE GI2801

Product Options

Thermal conductivity:

  • Thickness 50–100 mm: 0.034 W/m­­·K.
  • Thickness >100 mm: 0.035 W/m­­·K.

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