Fixing and buying guide
URSA 35 Cavity Wall Batt 3.69mtr sq (0.035W/mK) 100mm
What this product is and who it is for
URSA CAVITY BATT 35 is a rigid yet flexible mineral wool insulation batt for use in external cavity walls during new build masonry construction. It is intended for builders, contractors, and experienced DIY installers working on new-build projects where cavity wall insulation is required. The product is not suitable for retrofit applications or for use in cavities with existing masonry.
- Non-combustible glass mineral wool construction
- BBA approved for use in cavity walls
- Water-repellent additive for moisture resistance
- Thermal conductivity rating of 0.035W/mK
Sizing and pack contents
This product is supplied as a single batt measuring 3.69 square metres. The batt is manufactured at 455mm width to align with standard vertical wall tie spacings in cavity wall construction, eliminating the need for cutting to width and reducing on-site waste. The 100mm thickness is suitable for cavities of that depth.
- Coverage: 3.69 square metres per batt
- Width: 455mm (pre-sized for standard wall tie spacing)
- Thickness: 100mm
- Single batt per pack
Compatibility and installation requirements
This batt is designed for friction fitting between standard vertical wall ties in new external masonry cavity walls. The 455mm width is engineered to sit between typical wall tie spacings, allowing the product to be held in place by friction without additional fixings. It can be used for full cavity fill or partial fill applications depending on your cavity width and insulation requirements. Ensure cavity width is suitable before purchase.
- Suitable for new build masonry cavity walls only
- Friction fit between standard vertical wall ties
- Compatible with both full and partial cavity fill
- Check cavity width and tie spacing before ordering
Pre-installation checks
Before installation, verify that your cavity width accommodates 100mm thickness insulation and that vertical wall tie spacing aligns with the 455mm batt width. Ensure the cavity is clear of debris, mortar droppings, and obstructions that could prevent proper seating of the batt. The water-repellent additive provides protection, but the cavity itself must be clear and well-drained to function correctly. Wear appropriate personal protective equipment including gloves and respiratory protection when handling mineral wool.
- Confirm cavity width is suitable for 100mm thickness
- Check vertical wall tie spacing matches 455mm batt width
- Clear cavity of debris and mortar droppings
- Wear gloves and respiratory protection during handling