BigBlok: Super-insulating Cavity Closers for 125-300mm Cavities
Think big for thermally efficient construction
BigBlok - The sustainable system for low-carbon projects
BigBlok cavity closers have been developed to meet the demand for closures in buildings with cavities from 125mm to 300mm wide. Larger cavities that can accommodate more insulation are increasingly being specified on new-build properties to meet stringent thermal efficiency regulations and the requirements of the Code for Sustainable Homes.
Super-insulating, easy-fit, versatile cavity closer
The BigBlok cavity closer comprises a solid block of insulation making it ideal for low U-value construction. The simple slot-together system means you can quickly and cost-effectively close off window and door openings of any size in any type of wall.
The PVC-U cavity closer prevents thermal bridging and provides a brick-laying template. BigBlok cavity closers are compatible with all PVC-U, wood, steel and composite window and door types.
BigBlok closers make sustainable sense
The energy-efficient BigBlok cavity closure is an essential component for low U-value construction, helping your buildings to achieve higher ratings in the Code for Sustainable Homes.
What’s more, BigBlok cavity closers are manufactured entirely from post-consumer recycled PVC-U – waste plastic that might otherwise be sent to landfill.
Continuous, CSH-ready insulation
The integral insulation within BigBlok cavity closers provides continuous thermal insulation around the opening. It has a Global Warming Potential (GWP) of less than five and an Ozone Depleting Potential (ODP) of zero – meeting the requirements of the Code for Sustainable Homes.
Why choose BigBlok cavity closers?
- Creates rigid bricklaying template and seals walls with cavities up to 300mm wide – helping you to meet tougher thermal efficiency regulations
- Manufactured from 100% post-consumer recycled PVC-U – for a sustainable solution
- Closes opening with continuous CFC/HCFC-free insulation – reducing U-values and preventing thermal bridging
- Quick and easy to fabricate and fit, with straight cuts and slot-together fitting – saving time and money
- Compatible with PVC-U, timber, steel and composite doors and windows
- Tough, robust design – able to withstand the most demanding site conditions
- Extensive range of fitting options – to suit every building project
Sizes to suit every project
BigBlok cavity closers are available in a wide range of sizes to suit the latest building regulations: 125mm cavity, 140mm cavity, 150mm cavity, 170mm cavity, 200mm cavity, 250mm cavity and 300mm cavity.






