How and where to use guide
URSA 35 Cavity Wall Batt (0.035W/mK) 150mm X 1350MM X 455MM - 2.46 Sq Mtr Per Pack
Typical applications and installation
URSA 35 Cavity Wall Batt is installed horizontally between the inner and outer leaves of external masonry cavity walls during construction. The 455mm width is designed to fit between standard vertical wall tie spacings, allowing the batt to be friction fitted into place without requiring additional fixings or extensive on-site cutting. Installation should take place as the cavity wall is built up, with each batt layer placed horizontally and pushed firmly into position to ensure full contact with both wall leaves. The product can be used for full cavity fill (where the entire cavity is insulated) or partial fill (where insulation is installed with a residual air gap). Ensure batts are kept dry on site and protected from weather before installation.
- Friction fit between standard vertical wall tie spacings at 455mm width
- Install horizontally as cavity wall is constructed
- Suitable for new external masonry cavity wall construction
- Can be used for full or partial cavity fill applications
- Water-repellent additive resists moisture ingress in exposed cavities
- Non-combustible classification provides fire safety performance
Handling and on-site storage
Store URSA 35 Cavity Wall Batt in a dry location on site, protected from rain and ground moisture. The product is supplied in packs covering 2.46 square metres, with each batt measuring 150mm thick, 1350mm long, and 455mm wide. Handle batts carefully to avoid compression or damage, as this can reduce thermal performance. Wear appropriate personal protective equipment including gloves and a dust mask when handling mineral wool insulation, and ensure good ventilation during installation. Do not expose batts to prolonged moisture before installation, as this compromises the water-repellent properties and thermal effectiveness.
- Store in dry conditions, protected from rain and ground moisture
- Handle carefully to avoid compression or damage
- Wear gloves and dust mask during handling and installation
- Ensure good ventilation when working with the product
- Keep batts covered until ready for installation
Performance and limitations
URSA 35 Cavity Wall Batt delivers a thermal conductivity of 0.035W/mK, providing effective thermal insulation to meet Building Regulations requirements for new masonry cavity wall construction. The product holds British Board of Agrément (BBA) approval, confirming its suitability and performance standards. The non-combustible classification ensures compliance with fire safety requirements. The water-repellent additive provides protection against moisture ingress, though the product is not a vapour barrier and should not be used in applications where a separate moisture control strategy is not in place. The 455mm width is optimised for standard wall tie spacings; cavities with non-standard tie spacing may require cutting or alternative solutions.
- Thermal conductivity of 0.035W/mK meets Building Regulations requirements
- BBA approved for cavity wall insulation applications
- Non-combustible classification for fire safety compliance
- Water-repellent additive resists moisture, not a vapour barrier
- Optimised for standard vertical wall tie spacings
- Not suitable for cavities with non-standard tie spacing without modification
Maintenance and safety
URSA 35 Cavity Wall Batt requires no maintenance once installed within the cavity wall, as it is protected by the masonry leaves. The product should not be exposed to prolonged UV light or weather after installation. During installation, ensure adequate ventilation and wear appropriate respiratory protection, as mineral wool fibres can cause irritation if inhaled. Do not compress the batt excessively during installation, as this reduces its thermal effectiveness. If the cavity is damaged or opened after installation, handle any exposed insulation with care and replace any damaged sections to maintain thermal performance and moisture protection.
- No maintenance required once installed within the cavity
- Wear respiratory protection during installation
- Avoid excessive compression during fitting
- Protect from UV exposure and weather before installation
- Replace any damaged sections if cavity is opened