Wetherby Wall Systems Launches InteriA: Setting a New Standard for A-Rated, Moisture-Open Internal Wall Insulation

Wetherby Wall Systems, part of the ROCKWOOL Group, is delighted to announce the launch of InteriA, a next-generation Internal Wall Insulation (IWI) system, launched earlier this week. Developed in direct response to increasing industry demand for enhanced fire safety and compliant retrofit solutions, InteriA sets a new standard for solid wall property upgrades in the UK.

Internal Wall Insulation is a vital measure for improving the thermal performance of solid wall properties, particularly where external wall insulation is restricted by planning rules, heritage constraints, or site access. However, the market has lacked a fully developed system that combines strong fire resistance with the modern moisture management now identified as best practice by government guidance.

InteriA is engineered to address both challenges. Built from A-rated, non-combustible stone wool components, the system is designed to meet today’s more stringent safety expectations. Crucially, its moisture-open construction reflects advice from the Department for Business, Energy & Industrial Strategy (BEIS), which highlights that the lowest-risk IWI solutions are those that allow walls to dry to both sides, effectively reducing condensation risks and protecting long-term building health.

The InteriA system will provide a range of benefits for specifiers, housing providers, and programme managers:

Fire safety: Constructed from A-rated, non-combustible stone wool components.
Moisture management: Features a breathable, moisture-open design to reduce the risks of damp and mould.
Thermal efficiency: Offers slim build-ups that achieve refurbishment U-values with just 100mm of insulation.
Compliance: Developed in line with BEIS best practice guidance, PAS 2035, and the Building Safety Act.
Sustainability: Offers a 60-year design life, uses recyclable stone wool, and includes RockCycle waste recovery.

The InteriA build-up has been engineered with retrofit practicality in mind. Its slim profiles maximise internal space, and installation is designed to be quick and minimally disruptive. This makes the system particularly suited to occupied dwellings, phased upgrade programmes, and large-scale retrofit schemes.

Joe Ragdale, Technical Director at Wetherby Wall Systems, commented: “InteriA has been developed in direct response to what the industry has been calling for: an A-rated, moisture-open internal wall solution. It has been carefully designed to give specifiers, housing providers, and programme managers confidence that compliance, resident safety, and building durability are all addressed within one system.

By combining safety, sustainability, and compliance, InteriA represents a significant step forward for IWI solutions and will play a valuable role in helping the UK meet its carbon reduction and energy efficiency targets.”

To register your interest for training or to request further details ahead of the launch, contact Wetherby Wall Systems on 01942 717 100 or info@wall-systems.co.uk, or visit www.wall-systems.co.uk.