ISO-THERM Thin Internal Wall Insulation
Ultra-thin internal wall insulation for cold walls, condensation & damp prevention
Cold walls, condensation and mould are common problems in older UK properties — especially homes with solid brick walls or poor thermal performance.
ISO-THERM is an ultra-thin internal wall insulation system designed to help reduce heat loss, improve wall surface temperatures and minimise surface condensation without bulky insulation boards or major building work.
At only approximately 4mm thick, ISO-THERM provides a space-saving solution that can be installed directly onto internal walls while helping improve comfort and thermal efficiency throughout the home.
- Cold external walls
- Condensation-prone rooms
- Older solid wall homes
- Minimal space loss projects
ISO-THERM Internal Wall Insulation 7.125 m2 Kit
IN STOCK
£279.99 Inc VAT
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ISO-THERM Internal Wall Insulation Kit 14.25m² (2 Pack)
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ISO-THERM Internal Wall Insulation Kit 21.37m² (3 Pack)
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£799.00 Inc VAT
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ISO-THERM Internal Wall Insulation Kit 28.5m² (4 Pack)
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ISO-THERM Internal Wall Insulation Kit 42.75m² (6 Pack)
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£1,550.00 Inc VAT
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ISO-THERM – Internal Wall Insulation - 0.95m x 7.5m
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£233.99 Inc VAT
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ISO-THERM Internal Wall Insulation 0.95m x 7.5m (2 Pack)
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£460.99 Inc VAT
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ISO-THERM Internal Wall Insulation 0.95m x 7.5m (3 Pack)
IN STOCK
£695.99 Inc VAT
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ISO-THERM Internal Wall Insulation 0.95m x 7.5m (4 Pack)
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£905.96 Inc VAT
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ISO-THERM – Internal Wall Insulation - 0.95m x 7.5m
IN STOCK
£1,109.95 Inc VAT
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ISO-THERM Installation Guide (Step-by-Step)
Before installation, ensure the wall is solid, clean, and free from dust or loose coatings such as flaking paint. For best performance, ISO-THERM should be applied to bare plaster, with previous finishes removed. In many cases, skirting boards and architraves can remain in place, helping to minimise disruption.
⏱ Estimated time: 30–60 minutes per wall (depending on preparation required)
Ensure the wall surface is sound, clean, and free from dust or loose coatings such as flaking paint. For best results, ISO-THERM should be applied to bare plaster, with all previous wall coverings or coatings removed. Depending on their size, existing skirting boards and door architraves may not need to be removed, helping to reduce disruption during installation.
ISO-THERM adhesive is supplied ready to use. Apply directly to the wall using a 5mm notched trowel, forming horizontal ribs across the surface. The adhesive layer should not exceed 3mm in depth to ensure correct bonding and finished thickness.
⏱ Estimated time: 15–25 minutes per wall
This ensures even coverage and optimal bonding.ISO-THERM adhesive is supplied ready to use. Apply it directly to the wall using a 5mm notched trowel, forming horizontal ribs across the surface to a maximum depth of 3mm. This ensures even coverage and optimal bonding.
Starting from the top of the wall (similar to hanging wallpaper), roll the ISO-THERM insulation into the adhesive. Align edges carefully with the previous section. Smooth by hand, then firmly roll into place using a wallpaper press roller or similar tool to achieve full adhesion.
⏱ Estimated time: 20–30 minutes per wall
Ensure each section aligns closely with the previous piece. Smooth the insulation by hand, then firmly roll it into the adhesive using a wallpaper press roller or similar tool to achieve full contact.
Once the adhesive has fully cured, ISO-THERM can be plastered directly. After the skim coat has dried completely, finish with a breathable paint. The total finished wall depth, including plaster, is approximately 10mm.
⏱ Estimated time: 1–2 hours
| Small bedroom | 2–3 hours |
| Medium room | 3–4 hours |
| Large room | 4–5 hours |
Times assume reasonable wall condition and standard access.
DIY Installation – Suitable If:
You’re confident with basic wall preparation
You’ve used adhesives or wallpaper-style systems before
Walls are flat, dry, and structurally sound
Pros:
✔ Lower cost
✔ Flexible timing
✔ Minimal tools required
Considerations:
⚠ Care needed around sockets & switches
⚠ Surface preparation is critical
⚠ Poor adhesion affects performance
Professional Installation – Recommended If:
Walls show signs of damp or salt contamination
Property is older or solid-wall construction
You want a guaranteed, high-quality finish
Pros:
✔ Faster installation
✔ Correct detailing around reveals & fixtures
✔ Ideal for damp-prone areas
✔ Professional plaster finish
Best for: Whole rooms, basements, rental properties, or refurb projects.
Data Sheet & Case Study
ISO-THERM Internal Wall Insulation – FAQs
ISO-THERM is an ultra-thin (±4mm) patented polyester-based thermal insulation and damp-proofing material. It is designed to improve thermal performance, reduce condensation, and prevent mould growth on internal walls without significantly reducing room space.
Key Benefits
Ultra-thin insulation with high thermal performance
Helps prevent condensation, damp, and surface mould
Vapour permeable yet waterproof
Minimal loss of internal space
Suitable for residential and commercial use
Fast application with minimal disruption
ISO-THERM is suitable for internal walls affected by cold spots, condensation, damp, or mould. It can be applied directly to sound plastered walls and is ideal for homes, flats, offices, and commercial buildings.
Ease of Installation
ISO-THERM is lightweight, flexible, and easy to work with. It can be cut neatly around:
Light switches and sockets
Radiator brackets
Window reveals
Door architraves and skirting boards (often left in place)
Its flexibility allows it to fit awkward areas with ease, making installation minimally invasive.
The system is fixed using the dedicated ISO-THERM adhesive, typically trowelled onto the wall at around 5mm thickness. The ISO-THERM – Thin Internal Wall Insulation is then pressed and rolled into the adhesive. Once installed, the surface can be finished with a direct plaster skim coat.
The overall finished wall depth after plastering is approximately 10mm.
ISO-THERM is vapour permeable but waterproof. This means it allows the wall to breathe while resisting lateral damp transfer. It prevents the formation of surface salts such as nitrates and chlorides and significantly reduces the risk of mould growth.
Thanks to its high thermal efficiency, ISO-THERM helps raise internal wall temperatures, reducing cold surfaces where condensation typically forms. This improves comfort levels and energy efficiency within the property.
Large wall areas can be treated in a short space of time. Apart from plastering and painting, disruption is kept to an absolute minimum, making it ideal for occupied properties.
ISO-THERM Adhesive is a ready-to-use mineral adhesive composed of stabilised potassium silicate, siliceous aggregates, quartz sand, and specialist additives. It is vapour permeable, water repellent, and designed specifically for use with the ISO-THERM system.
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