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Rockwool Cavity Wall Building Slabs

Standard Rockwool Product, generally readily available in most thickness’s at the lower densities such as 45kg/m² and 60kg/m². As the slab densities increase, and product popularity declines, short lead times will apply.

Product Functions

The Rockwool Cavity insulation is a rigid full-fill insulation solution for masonry cavity wall construction, suitable for use in new builds or extensions. Lightweight and easy to handle, the batts are simple to install and provide a close fit against brick and blockwork, adapting to imperfections in the cavity wall.

The high performance Partial Fill Cavity Slab is a semi-rigid partial fill insulation solution for masonry and framed cavity wall construction. It is designed to withstand typical conditions on-site and absorb any irregularities on the inner leaf. Consists of a robust outer surface engineered to a resilient inner face. The slabs knit together when tightly butt jointed, eliminating heat loss caused by gaps.

Product Description

Rockwool high performance Partial Fill Cavity Slab consists of layers of bonded, water repellent rock wool formed into resilient slabs using a resin binder; the slabs are heat cured and cut to standard sizes of 455mm x 120mm.
Rockwool manufacture the following thickness's (millimetres) ... 30, 40, 50, 60, 70, 80, 90, & 100.
All slabs have a belt mark covering one face. The slabs are normally positioned with this face outermost.

Insulation retaining fixings approved for use with this system are as follows ...

    Rockwool Building Slabs for installation versitility around the house
  • Vista VE 2/VE-4 tie with V-23 retaining clip
  • Lexsuco clip with retaining washer
  • Ancon Staifix RT2 with AC Universal Clip
  • Catnic BB-3 Tie and IRC 85 ClipAncon ST1 Type 1 Tie with Heavy Duty Clip
  • Hemax 90S Heavy Duty Tie and Heavy DutyRetaining Clip
  • Hemax 82 Tie with Universal Retaining Clip.

Unfortunately, we do not supply the retaining clips mentioned above.


Product Benefits

BBA certified for all exposure zones
Outstanding thermal and fire insulation
Does not require TCBs
Prevents water transmission from the outer to inner leaf
Non-combustible (Euroclass A1)
Superior fit against blockwork
No sagging or slumping


Product Performance

Durability

Rockwool continues to work throughout the lifetime of the building. As well as reducing the heat needed to keep buildings warm in winter, stone wool insulation also maintains a cool interior temperature in summer. It’s energy efficient as well as being environmentally friendly all year round

Fire

All Rockwool RW slab products, either un-faced or with an aluminium foil or glass fleece on one or both surfaces, achieve an A1 classification in accordance with BS EN 13501-1 and therefore comply with the requirements of non-combustible materials/products, as defined in all UK and Ireland Building Regulations.

Water resistance

Rockwool RW Slabs are highly water repellent and non-hygroscopic

Thermal performance

For general building applications (Lambda 90:90) at temperature 10 degrees C:

Rockwool RWA45 slab = 0.035 W/mK | Rockwool RW3 slab = 0.034 W/mK | Rockwool RW5 slab = 0.034 W/mK

Handling and Storage

Rockwool RW slabs are light and easy to cut to any shape with a sharp knife. They are shrink wrapped in polyethylene and supplied on pallets which are shrouded with a waterproof hood suitable for outside storage.

All standard un-faced slabs are manufactured 1200 x 600mm. All foil faced and tissue faced slabs are manufactured 1000 x 600mm. The standard thickness range of Rockwool RW slabs are shown in the table below. * Denotes thickness also available as ‘standard’ with white or black tissue facing (not foil facing). All foil faced and tissue faced slabs (other than shown above) are non -standard and will be subject to minimum order quantities.



Product availability indicators

Rockwool Cavity Batts - Price and Availability Advisory:

Presently there are no availability restrictions.

Excellent = Product Availability Excellent Good = Product Availability Good Fair = Product Availability Fair Poor =  Product Availability Poor Undetermined = Product Availability Undetermined
Availability relies on stock levels at closest depots and upon transport logistics to effect deliveries


Technical Data

Properties Details
Dimensions 455mm x 1200mm
Thickness 50mm - 170mm
Thermal Conductivity 0.037 W/mK
Fire Properties Euroclass A1
Water Repellency Water Repellent
Vapour Resistivity Negligible
Environmental Zero ODP & GWP
Certification BS EN 13162, ISO 14001: 2004
Standards BBA 94/3079 | KeyMark LPCB 022e | Kitemark KM06661

Product Information and Certification

Links to manufacturer's information. Click to download in a separate browser window.

Rockwool Cavity Slab Datasheet | Rockwool Cavity Wall Slab BBA Certificate | Rockwool meeting Part L Building Regs.

 

Rockwool Building Slab Range - Certification

Product Certification

Rockwool has been examined by the British Board of Agrément and granted BBA Certificate 94/3079 for use in all exposure zones for buildings up to 12 m in height and for buildings over 12 m and up to 25 m in height in zones where the exposure factor does not exceed 120.

To comply with the requirements of the Agrément Certificate, and to ensure trouble free performance, the masonry walls must be built in accordance with BS 5628:Part 3: 1985 or BS 5390: 1976, as appropriate, and the workmanship on site must comply with BS 8000: Part 3: 1989.

Rockwool Slabs conform to BS EN 13162: 2001: Thermal insulation products for buildings – factory made mineral wool (MW) products specification.

They also satisfy the requirements of BS 5422: Method for specifying thermal insulating materials for pipes, tanks, vessels ductwork and equipment.


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    Thermal / acoustic slabs suitable for roofs, ceilings, walls, partitions, floors, and can be fitted between timber and metal frames.

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Installing Rockwool Cavity

Remove excess mortarIt is the installer's responsibility to ensure that Rockwool Cavity is fitted in accordance with the recommendations of their data sheet.

The installation of the batts should commence below the DPC (preferably by at least 150mm) with no risk of capillary action to minimise cold bridging. The bottom row of ties should be at 450mm centres horizontally. If necessary, the width of the first course of batts can be cut to suit the height of the next row of wall ties. The width of cut batts should always be 5mm greater than the width to be insulated, e.g. wall tie centres.

It is recommended that the external leaf be constructed ahead of the internal leaf so that any mortar protruding into the cavity space from the back of the external leaf can be cleaned off before installing the batts.

Build up a complete section of the leading leaf to one course above the next row of wall ties spaced at max. 900mm horizontally.

Ensure that all mortar joints are properly filled, particularly the perpends.

Before installation of each course of batts, excess mortar must be removed from the inside face of the leading leaf and mortar droppings cleaned from the exposed edges of the batts. This is made easier by the use of a cavity board.

This sequence should be maintained progressively up to wall-plate (or cavity tray) level. It is important that the insulation is carried to the highest level possible in either case.

5 Fit Rockwool Cavity by compressing between the two rows of wall ties to form a clean and tight butt jointed course. Wall tie drips should be located centrally in the Batts. Ties must be inclined downwards towards the outer leaf.

It is essential that all joints between Rockwool Cavity batts are clean and tightly butted.

Raise the second leaf to the same level as the batts.

The as-built cavity width must not exceed the following dimensions:

Nominal Batt thickness (mm)

Maximum as-built  clear cavity width (mm)

65

75

80

95

90

105

100

115

110

125

Repeat this sequence to the top of the wall. If not, protect the top of the batts with a cavity tray.

To prevent water penetration to the inner leaf during driving rain, it is essential that no gaps are left between the batts.Installation of Batts in gable end wall

Cut the batts cleanly, using a sharp, long bladed knife and a straight edge.

Fit the batts closely around wall openings. Slit the batts neatly where additional wall ties occur. Do not impale or tear them. At corner joints, edges must be cut accurately to ensure close butting.

Cut the batts accurately to fit between wall ties, if not conventionally coursed. Ensure closely butted joints by cutting the batts 5 mm larger in size than the wall-tie centres.

Avoid the build up of mortar on cavity trays.

Where make-up pieces have to be used, ensure that they are installed with the same direction of grain.

Protect the top of the cavity wall insulation at the end of the work period with a waterproof covering.

Store or cover Rockwool Cavity not in use and protect from site damage



External Walls - Masonry Cavity Walls – Full Fill

Again remove excess mortarRockwool Cavity is extremely easy to install; cutting is simple (preferably with a long bladed knife and straight edge). The construction of the batts, and flexibility along their length and width, allows tight ‘knitted’ joints to be obtained easily on site.

If a batt requires cutting, its width should always be 5mm greater than the width to be insulated, e.g. wall-tie centres, ensuring a tight/closely butted installation.  

The use of Rockwool Cavity does not affect the choice of ties to BS 1243 (or DD140), which should be selected according to structural requirements. It is the contractor’s responsibility to ensure that Rockwool Cavity is fitted in accordance with the recommendations on the data sheet for Rockwool Cavity.  

The installation of the batts should commence below the DPC to minimise cold bridging. The bottom row of ties should be at 450 mm centres. If necessary, the width of the first course of batts can be cut to suit the height of the next row of wall ties. The width of cut batts should always be 5 mm greater than the width to be insulated, e.g. wall tie centres.  

It is recommended that the external leaf be constructed ahead of the internal leaf so that any mortar protruding into the cavity space from the back of the external leaf can be cleaned off before installing the batts. Build up a complete section of the leading leaf to one.
Build up a complete section of the leading leaf to one course above the next row of wall ties spaced at max. 900 mm horizontally.

Ensure that all mortar joints are properly filled, particularly the perpends.  

Before installation of each course of batts, excess mortar must be removed from the inside face of the leading leaf and mortar droppings cleaned from the exposed edges of the batts. This is made easier by the use of a cavity board

This sequence should be maintained progressively up to wall-plate (or cavity tray) level. It is important that the insulation is carried to the highest level possible in either case Fit Rockwool Cavity by compressing between the two rows of wall ties to form a clean and tight butt jointed course  Wall tie drips should be located centrally in the batts. Ties must be inclined downwards towards the outer leaf.

It is essential that all joints between Rockwool Cavity batts are clean and tightly butted.  

Raise the second leaf to the same level as the batts.  

The as-built cavity width must not exceed the following dimensions:

Nominal Batt thickness (mm)

Maximum as-built  clear cavity width (mm)

50

60

65

75

75

85

80

95

90

105

100

115

Repeat this sequence to the top of the wall. If not, protect the top of the batts with a cavity tray. Cavity trays should incorporate stop ends and have weep holes at approximately 450 mm centres. Cavity trays should be continuous across closely spaced openings.

Construction and installation guidance

The outer leaf is the first line of defence against rain. Its effectiveness will be improved if attention is paid to the following points:

The width of the cavity should be designed after consideration of the dimensional tolerances of the components which make up the wall. An extra 5mm above the nominal batt thickness will normally be sufficient.

Select porous bricks, which in periods of brief, heavy showers will absorb the moisture. A non-absorbent brick will channel water into the mortar joints.

Cavity trays should be continuous across closely spacedSelect a lime mortar mix that does not contain detergent-type plasticisers, which reduce the water resistance of the joints.

Specify weather-struck, flush or bucket-handle joints. Recessed joints increase the risk of water penetration. Ensure all bed joints and perpend joints in the external wall are fully filled with mortar.

Cavity trays should incorporate stop ends and have weep holes at approximately 450mm centres (max 900 mm centres).

Cavity trays should be continuous across closely spaced openings (Figure 1) and stop ends provided.

Vertical DPCs at wall openings should project at least 25 mm into the cavity. (See Rockwool Cavity Closers Data Sheet for details.)

The use of Rockwool Cavity does not affect the choice of ties to BS 1243 (or DD140), which should be selected according to structural requirements.


Contact Manufacturer

Rockwool Insulation Limited

Pencoed Bridgend CF35 6NY United Kingdom

Rockwool Customer Service

Telephone: +44 (0) 1656 868400
Email: technical.solutions@rockwool.co.uk
Web site: Rockwool Home Page

Contact us

Insulation Online Limited

27 Massetts Road, Horley, Surrey, RH6 7DQ, UK

Telephone: 0333 8000 828

Facsimile: 0333 7000 797

Email: enquiries@insulation-online.com

Web site: www.insulation-online.com

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