Knauf DriTherm 37 Cavity Slabs

What Is DriTherm 37? 

DriTherm 37 Cavity Slabs are glass mineral wool insulation boards specifically designed for full-fill cavity wall applications.

These slabs are treated with a water-repellent additive, ensuring they resist moisture ingress and maintain their integrity over time. They are non-hygroscopic, meaning they do not absorb water or promote the growth of mould or bacteria, which helps to prevent issues such as dampness and poor indoor air quality.

With a thermal conductivity of 0.037 W/mK, DriTherm 37 provides excellent thermal insulation, reducing heat loss through cavity walls. This translates into improved energy efficiency, contributing to lower heating costs and a more comfortable indoor environment.

The slabs are precision-cut to fit snugly between standard wall ties, ensuring a quick and efficient installation process with minimal cutting or waste. 

Their semi-rigid, friction-fit design ensures complete cavity fill, preventing gaps that could otherwise lead to thermal bridging or air leakage, further optimising energy efficiency.

In addition to their thermal benefits, DriTherm 37 Cavity Slabs are Euroclass A1 fire-rated, meaning they are non-combustible and provide essential fire resistance within the building envelope. This makes them an important safety feature, helping to prevent the spread of flames in the event of a fire.

Manufactured with sustainability in mind, DriTherm 37 Slabs are made from a high percentage of recycled glass and are fully recyclable at the end of their life cycle. 

Applications

Knauf Dritherm Cavity Slab 37 is purposed for use in masonry cavity external walls where a full-fill insulation solution is required.

A masonry cavity wall is made up of two leaves (or skins); an inner leaf and an outer leaf. The "cavity" is simply the gap between these two masonry walls. 

DriTherm cavity slabs are considered to be an effective thermal insulation solution for buildings up to 12m high and in multi-storey applications up to 25m high.

Benefits

• Non-combustible full-fill insulation eradicates the need for cavity barriers.
• The slabs are 455mm wide to suit standard vertical wall tie spacing, ensuring a closed joint with adjacent slabs.
• Compatible with standard vertical wall ties, banishing the need for retaining discs. 
• Superior environmental sustainability/low environmental impact.
• Made from up to 80% recycled glass, minimising the need for mineral raw materials.
• Rigid nature ensures that they do not sag or droop over time.

Specifications

• Suitable for external masonry cavity walls
• Non-combustible A1 Euroclass Reaction to Fire classification - minimising the risk of fire spreading throughout the cavity
• 0.037 W/mK thermal conductivity - excellent thermal performance
• Water repellent
• Rigid and compact
• Zero Global Warming Potential (GWP)
• Zero Ozone Depletion Potential (ODP) 
  
  

Certifications

• Manufactured in accordance with BS EN 13162, ISO 50001 Energy Management Systems. 
• BBA certified - 95/3212 - approved for use in structures up to 12m in height in any exposure zone, as well as in multi-storey applications up to 25m in height.

Installation Considerations

• Cavity Cleanliness: Before installation, ensure the cavity is free from mortar droppings, debris, and other obstructions. A clean cavity ensures proper fitting and helps avoid performance issues.
• Wall Tie Spacing: DriTherm 37 Cavity Slabs are designed to fit snugly between standard wall ties. Ensure that wall ties are correctly positioned, clean, and placed to allow for a seamless, secure fit of the insulation.
• Friction Fit: These slabs are semi-rigid and designed to fit tightly between the wall ties without gaps. They should be friction-fit for full coverage and to prevent air leakage.
• Adequate Coverage: Ensure that slabs fill the cavity completely and are installed in continuous layers. Stagger the joints between courses to avoid thermal bridges and to maintain consistent insulation performance.
• Protection During Storage and Installation: Although the slabs are water-repellent, they should be protected from excessive moisture during storage and installation. Store them in a dry, covered area and ensure they are kept off the ground.