ISO-THERM Ultra-Thin Thermal Wall Insulation – 4mm Breathable Internal Wall Insulation
Ultra-Thin Thermal Insulation for Cold Walls, Condensation and Mould Prevention
ISO-THERM is an innovative, ultra-thin internal wall insulation system designed to improve the thermal performance of cold walls, reduce the risk of surface condensation and help prevent conditions that encourage mould growth.
Manufactured from a specially woven, 100% polyester-based non-woven material with a water-based flame-retardant acrylic coating, ISO-THERM combines thermal performance with a flexible, lightweight construction.
At just 4mm thick, ISO-THERM provides a practical alternative to conventional bulky internal insulation systems, making it particularly suitable for properties where preserving valuable room space is important.
The material is installed directly onto suitable, sound internal walls using a specially formulated fibre-reinforced ISO-THERM Adhesive, applied at approximately 5mm thickness. Once installed, the insulation can receive a compatible plaster skim finish of approximately 2–3mm, creating a smooth surface ready for decoration.
With a complete installed system thickness of approximately 10mm, ISO-THERM provides a discreet solution for improving the comfort and thermal performance of existing internal walls without significantly reducing room dimensions.
Key Features & Benefits
- Ultra-Thin 4mm Insulation – Improves wall thermal performance without the bulk of traditional internal insulation boards.
- Improved Thermal Efficiency – Demonstrated a 21.6% improvement in wall U-value under the stated test conditions, reducing it from 1.898 to 1.488 W/m²K.
- Helps Reduce Surface Condensation – Improving internal surface temperatures can reduce the likelihood of condensation forming on cold walls.
- Highly Resistant to Surface Mould – Helps create conditions less favourable for mould growth by improving wall surface thermal performance.
- Flexible and Lightweight – Easily cut and shaped around sockets, light switches, corners and other wall features.
- Minimal Room Space Lost – Approximately 10mm overall installed thickness, including adhesive and skim coat.
- Breathable Yet Water-Resistant – Vapour-permeable material with waterproof properties, designed to help manage moisture movement.
- Direct Plaster Skim Finish – Accepts a compatible plaster finish for a smooth, ready-to-decorate surface.
- Fast and Convenient Installation – Can be applied directly to suitable sound plastered walls, reducing preparation and disruption.
- Ideal for Property Refurbishment – Suitable for consideration in homes, rental properties, commercial premises and building renovation projects.
Why Choose ISO-THERM Internal Wall Insulation?
Many properties suffer from cold internal wall surfaces, particularly solid-wall buildings, older homes and rooms with limited insulation.
When warm, moisture-laden indoor air meets a cold wall, condensation may form, creating conditions that encourage black mould growth and damage to decorative finishes.
ISO-THERM is designed to improve the thermal performance of the wall surface, helping to reduce the temperature difference between the wall and the surrounding room.
This can make the internal surface less prone to condensation under suitable indoor temperature and humidity conditions.
Unlike conventional internal insulation systems that can require thick boards, new plasterboard and extensive alterations to fixtures, ISO-THERM achieves its thermal improvement with a remarkably thin construction.
Its flexible composition allows the material to be cut around existing fittings, and in many installations, door architraves and skirting boards can remain in place.
This makes ISO-THERM particularly attractive for refurbishment projects where installation speed, minimal disruption and maintaining existing room dimensions are important.
Thermal Performance – 21.6% U-Value Improvement
ISO-THERM has demonstrated an improvement in wall thermal performance under the reported test conditions.
The tested wall U-value improved from 1.898 W/m²K to 1.488 W/m²K, representing a reduction of approximately 21.6%.
A lower U-value indicates reduced heat transmission through the tested wall assembly.
This improved thermal performance can help increase internal surface temperatures and reduce the likelihood of condensation forming on cold wall areas.
Actual improvements will vary depending on existing wall construction, insulation levels, installation details and environmental conditions.
ISO-THERM should not automatically be considered a replacement for the insulation thickness required to meet applicable building regulations.
Helps Reduce Condensation and Surface Mould
Surface condensation is a common problem on cold external walls, behind furniture, around window reveals and in rooms with poor ventilation.
When wall surfaces remain cold, moisture from indoor air can condense, increasing the risk of mould growth.
By improving wall surface thermal performance, ISO-THERM helps make these areas less susceptible to condensation.
The material has also demonstrated 0% fungal growth after four weeks at 25°C under the specified laboratory test conditions.
This indicates strong fungal resistance of the tested material, although it does not guarantee that mould will never develop on the finished wall.
Adequate ventilation, suitable heating and control of indoor humidity remain important.
Breathable and Water-Resistant Construction
ISO-THERM combines vapour permeability with waterproof properties.
Its construction is designed to allow water vapour movement while resisting liquid water penetration through the insulation material.
This can be beneficial in suitable internal wall insulation applications where moisture management and vapour permeability are important considerations.
The material’s water-resistant characteristics may also help reduce lateral moisture transfer throu