SureCav25 Advantages



SureCav25 will prevent any water ingress due to wind-driven rain, even in the most severe weather zones. This means that just a 25mm clear cavity can be used instead of the usual 50mm or even75mm in some cases.

SureCav25 is BBA approved and accepted by LABC and NHBC!

This feature of SureCav25, in maintaining a perfectly consistent, clean and moisture-free clear cavity, gives rise to the situation where a brick outer leaf can be specified. Ordinarily, it would not be possible to keep the cavity clean with just a 25mm gap. But now, with SureCav25, the wall can be built with full confidence. What is more, where a 100mm overall cavity is specified, U-Values of just 0.18 W/m2K can be achieved by installing 75mm of insulation.

It is our experience that a clear section of the cavity should always be present in the construction of the walls. 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. 


SureCav25 reduces overall wall width


Standard construction


Zone: Severe exposure
75mm clear cavity required and 75mm insulation
Overall cavity width = 150mm

This was the only way to build cavity walls accepted by local authority until now! 

With SureCav25

Zone: Severe exposure
SureCav25 (25mm clear cavity) and 75mm insulation
Overall cavity = 100mm

50mm saved in the cavity width for each wall.

Installing SureCav25 guarantees moisture and mortar-free clean cavities!

more advantages of surecav25 with brick:

  • Provides for lower U-Values in an original 100mm cavity
  • Protects against wind-driven rain in any exposure zone
  • Ensures clean cavities that are permanently free from mortar contamination
  • Maintains a moisture-free environment, protecting the envelope of building
  • In some situations, it is possible to gain up to 1.25% internal floor space where the cavity
    is reduced to 75mm
  • A 1.25% space gain is equal to gaining 1 extra house on an 80 house site
  • Holds the insulation to the inner leaf, enabling it to work to its full efficiency
  • Ensures a consistent 25mm air gap

U-Value chart

Helps to reduce U-Values

SureCav25 proves to be an excellent product in helping to reduce U-values as well as keeping the overall wall width as narrow as possible. 
Take for example, a building currently under construction 
that has a 100mm solid timber-frame and 100mm insulation external to the frame.

The U-Value calculated for this type of wall is less than 0.13 W/m2K


See SureCav25 product details here


The SureCav25 panels hold the insulation in place at all times, enabling it to work to its full efficiency. This will bring an immediate reduction in heat loss, noise levels and energy costs, meaning less energy required from the power stations that burn fossil fuels to produce electricity. Reduction in condensation and moisture build-up will give a warmer home. SureCav25 ensures that the insulation is held firmly against the inner leaf. It is to your advantage to install the maximum width of insulation possible to achieve the lowest "U" values. Installing SureCav25 guarantees a clean and moisture free cavity.

Clean Cavities

 We are often asked how it is possible to maintain clean cavities with just a 25mm air gap. In the past, it would have been impossible to build with  such a narrow clear cavity without some mortar contaminating the wall-ties. But here's the truth! The25mm air gap formed by SureCav25 maintains a uniform clear cavity that is absolutely free from mortar or moisture contamination! The interlocking panels, properly connected with the joining strips, form a complete barrier as the outer leaf is constructed. As the outer masonry leaf is built, there is no way for the mortar to penetrate the SureCav25 panels.

This photo  illustrates well the positioning of the cavity tray and how the insulation is cut to produce its maximum effectiveness. In this case, by not immediately backfilling the void behind the stone, more area of stone can be built without the danger of the wall bellying out of true. Once the mortar has cured, then the backfilling can proceed as normal.

Protection against wind-driven rain

You will notice in the photo, the "wall of plastic" provided by the SureCav25 panels will prevent water ingress from wind-driven rain when building external wall with any recognised masonry finish. A moisture and mortar-free 25mm clear cavity will be maintained that is easily ventilated. The unique shape of the pods ensures that if any moisture should be present, it is always directed to the outer leaf.

A further benefit of using SureCav25 is the protection afforded against the damaging effects of wind-driven rain.
Over the course of a prolonged exposure, the external masonry leaf will become saturated with water, which will much more likely be able to breach the cavity. This build-up of moisture often results in mould, mildew and condensation.
Damage readily occurs to wall-ties, insulation, wall plates and even the timber-frame and installed joinery.