Rigid foam boards cannot accommodate the imperfections of the inner leaf which can create gaps and air movement behind the boards.

The thermal performance of foil faced rigid foam boards is dependent on effective entrapment of the blowing agent. Dust or mortar staining on the foil facing can reduce the thermal resistance of the residual cavity.

DriTherm Cavity Slabs are rigorously tested and are formally guaranteed for 50 years to prevent the transmission of liquid water from the outer masonry leaf to the inner masonry leaf. Not all competitors offer an equivalent formal guarantee.

The entire DriTherm Cavity Slab range is BBA certified for all exposure zones and has a 35 year successful performance heritage with millions of cavities already insulated.

With DriTherm Cavity Slabs in full fill applications there is no requirement for special retaining discs or cavity barriers.

By fully filling the cavity, problems associated with partial fill cavities can be avoided, for instance mortar droppings and snots can be easily removed.

Rigid foam boards are more difficult to cut and require a greater degree of care and time to install correctly.

The integration of special retaining discs and cavity barriers adds time, cost and complexity to the installation process.

Badly fitting or missing retaining discs leading to the misalignment of the rigid foam boards can compromise the thermal performance of the wall.

Rigid foam boards are more prone to installation damage which may increase site wastage and compromise the quality of the final installation.

Glass mineral wool is inherently good at absorbing sound and allows sound energy to be dissipated within the body of the insulation.

This helps to reduce flanking sound transmission along the wall cavity and can also provide sound protection from external noise sources.

Due to glass mineral wool’s ability to reduce the noise transmitted both through the structure of a building and also via concealed cavities, it is generically referenced throughout national Building Regulations and Robust Details for uses as an acoustic cavity barrier.

Rigid foam boards by comparison offer no sound absorption and cavity walls built with these products require cavity stops at junctions with separating walls to prevent flanking sound transmissions.

DriTherm cavity slabs are unbeatable Euroclass A1 fire rated due to the non combustible nature of glass mineral wool.

DriTherm cavity slabs will not support combustion even in direct, prolonged contact with flames.

Furthermore, they emit no toxic fumes or smoke, the two biggest hazards to health and life in the event of a fire.

DriTherm cavity slabs may also be considered as a cavity barrier when tightly fitted between masonry leaves where an insulated wall connects with the cavity of a wall without cavity insulation.

DriTherm cavity slabs may also be considered as a cavity barrier when used at the junction of a separating wall with an external cavity wall.

Rigid foam boards by comparison ignite easily and burn rapidly – they also generate large amounts of smoke and toxic fumes in the event of a fire.

With a wide range of thermal solutions, the DriTherm range is able to achieve compliance with current Building Regulations right through to the highest levels of the Code for Sustainable Homes.

High thermal performance can be achieved within an overall 300mm wall width. 

The necessity for a residual air gap restricts the flexibility of rigid foam boards when it comes to cavity widths.

DriTherm has an unbeatable Green Guide A+ rating.

DriTherm is made from glass mineral wool which has an extremely low environmental impact.

The major ingredient of DriTherm is silica sand, the earth’s most abundantly occurring mineral.

DriTherm is manufactured from glass mineral wool which contains a high content of recycled glass bottles.

DriTherm can be recycled at the end of a building’s life.

Rigid foam boards by comparison are derived from petrochemicals.

State of the art packaging techniques allow the compression of more insulation in a smaller space than almost any other insulant resulting in better vehicle utilisation and reducing the environmental impact of transportation.

Our innovative Supakube packaging ensures 24 houses worth of insulation per lorry load thereby maximising handling and transport efficiency (based on target u-value of 0.27 in a 100mm cavity).

Only 12 houses worth of insulation per lorry load are possible with comparable rigid foam board products (based on target U-value of 0.27 in a 100mm cavity).

DriTherm Cavity Slabs rely on entrapped air for their thermal properties; they are zero Global Warming Potential (GWP) and zero Ozone Depleting Potential (OPD) products.

Long term performance – DriTherm will last for the life of the building and beyond as the product can be reused and recycled.

The insulation properties of rigid foam boards are achieved through the use of blowing agents combined with diffusion-tight facings such as aluminium foil.