Eco-friendly, cost-effective 25mm cavity-wall technology!

The original SureCav50 was designed to form a lightweight alternative to backing blocks that would increase floor space and act as a barrier to wind driven rain, effectively providing a consistent mortar and moisture-free 50mm clear cavity. Now, SureCav25 forms a 25mm clear cavity, making extra room for insulation or for creating even more floor space.

  • Advantages of SureCav 25

    Below, we list the advantages of SureCav25. They are the same as for Surecav50 but with the added benefit of an extra 25mm of space!

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Eco-friendly, cost-effective 25mm cavity-wall technology!


  • Lowers U-Values by making more room for extra insulation
  • Option to increase internal room space
  • Maintains an essential air gap
  • 25mm permitted residual cavity rather than 50mm or 75mm
  • BBA certificated
  • Suitable for use with brick, stone, flint or slate external finishes
SureCav25 with Ashler stone


Significant cost savings

SureCav25 forms a 25mm clear cavity providing a backing board for the stone, slate, brick and flint outer leaf. It halves the cost of building with a backing block and halves the CO2 footprint, compared to using a concrete block backing wall and is fully BBA certified. 

Gain more space with SureCav25!

A reduction in wall thickness of 25mm will increase the internal dimensions of the property by 50mm in each direction and result in an average of 1.25% increased floor space. Removing the 100mm backing block adds another 5% internal space. This can rise to over 7% additional floor space in very severe weather zones, where a 75mm clear cavity may be required.

Consider this: An overall 7.5% gain is equivalent to the floor space of 6 extra houses on an 80 house site!

Reduce the width of the wall with SureCav25


Reduce your carbon footprint!

SureCav is made from 100% recycled plastic and almost halves the carbon footprint when compared to the weight of the concrete blocks it replaces.
More about eco-friendly SureCav helping the environment here

40 tonnes of 100mm concrete blocks

Light and easy to handle!

The equivalent wall area of SureCav panels, that would require 40 tonnes of 100mm concrete blocks, will easily fit into a pick-up truck, saving valuable site storage space.

SureCav equivilent

Experience the future of cavity-wall construction!

Now drive down U-Values! SureCav25 allows for more room in the cavity for insulation, thus enhancing the thermal performance of the wall. Where heat conservation is the prime concern, SureCav25 will release an additional 25mm in the cavity that can be used for extra insulation.

This example shows how a 100mm overall cavity width, comprising 75mm board insulation and a 25mm clear cavity using SureCav25, can achieve U-Values as low as 0.18 W/m²K. Alternatively, a 125mm overall cavity width, comprising 100mm board insulation and a 25mm clear cavity using SureCav25, can achieve U-Values as low as 0.15 W/m²K. (Figures calculated using Kingspan Kooltherm K108 Cavity Board insulation and the Kingspan U-Value calculator)

Consistent clear cavity

Now guarantee clean and moisture free cavities with SureCav25! The SureCav25 cavity backing system is used to form a consistent 25mm clear cavity in new masonry or timber frame walls of domestic and non domestic buildings.

The 25mm air gap between the outer layer of masonry and the insulation, coupled with the moisture beating design of the SureCav25 panels, will prevent any water penetration. The SureCav25 panels will also hold the insulation in place, adding to its effectiveness in preventing heat loss.

Protection from wind driven rain

In very severe exposure zones there is sometimes a requirement for a clear cavity up to 75mm, however, you can use SureCav25 and save up to 50mm space! As well as the SureCav panels preventing moisture from bridging the cavity, the unique shape of the SureCav pods directs any moisture to the outside leaf, protecting the fabric of the building.

Reasons to build with SureCav25 in all exposure zones:

  • BBA approval to form a 25mm clear cavity
  • Forms a barrier to protect from wind-driven rain
  • Excellent surface for the construction of any external wall masonry but shields the cavity and inner leaf from water ingress
  • Ideal for timber-frame and traditional block inner leaf, as well as SIPs, SFS and ICF construction