United Kingdom


Baumit OpenSystem:
Breathable Insulation

Thermal insulation plays a vital role in ensuring a consistent and comfortable temperature is created within a house to provide a healthy living space. In a correctly insulated house, there is a comfortable warmth in the winter, yet the house is protected from overheating in the summer months. Creating a balanced indoor climate, with minimal fluctuations throughout the year.

To achieve this, Baumit have created a truly unique, high performing EWI system – Baumit OpenSystem.

  • Highly permeable thermal insulation system
  • Optimal indoor climate through breathable buildings
  • Insulation for every façade, new building and renovations

Comfort at all times

Through everyday living in a four-person family home, the household can produce up to 20 litres of moisture per day. Without correct ventilation this moisture can lead to condensation, damp and mould if not regulated.

 The high vapour permeability (or breathability) of the Baumit OpenSystem thermal insulation system, helps to greatly eliminate this humidity without undue heatloss. The system has the same vapour permeability as brick masonry, so works in harmony with existing brick walls, restricting excess vapour build up from the inside out.

Ideal for updating older buildings

If you have an older building which is suffering from poor insulation, damp and or moisture, Baumit OpenSystem, our patented EWI solution is ideal. The system adhesive, Baumit OpenContact, consistently works to extract the moisture from the brick and this passed through the breathable insulation boards away from the walls.

This is the most effective EWI system for insulation of single brick walled buildings, causing the least disruption during installation as all works take place externally.


  • Homogenous wall build-up
  • Breathable and highly vapour permeable
  • Prevents condensation from water vapour
  • Ensures a comfortable indoor living climate
  • Reduces building time as it dries out more quickly

The System

Every element in the OpenSystem has been specially developed, tested and improved upon over time to be as efficient as possible when working together as a system. The heart of the system is the insulation boards. The polystyrene based board feature a patented system of holes to ensure rapid drainage of water vapour, however even with ‘holes’ provides the same level insulation as regular insulating boards.

System components

Open System

Base- new masonry or original base
1. FixingBaumit StarTrack adhesive anchors bring many advantages. No thermal bridges and allows a good adhesion without additional fixing.
2. Adhesive - Baumit OpenContact White is a vapour-permeable, fibre-reinforced adhesive and base coat render. It is made from breathable aerated lime and is extremely weather-resistant.
3. Insulation - Baumit OpenTherm is a highly-breathable, thermal insulation made from expanded polystyrene. The insulation is specially designed for brickwork and similarly breathable masonry. 
4. Reinforcement - Baumit StarTex is a warp-resistant and alkali-resistant glass fibre mesh that is used to produce a reinforced mortar layer on torn old rendered facades.
5. Primer - Baumit PremiumPrimer is a ready-to-use primer for synthetic and mineral decorative finishes. It has high covering power and regulates absorption. 
6. Final Topcoat - Baumit NanoporTop is a ready-to-use, pollution-resistant render. It helps to protect and preserve facades using photocatalysis technology.

With Added Baumit Nanopor Technology

Baumit NanoporTop provides the final coating. This render acts as a topcoat to the External Wall Insulation and protects the surface from dirt and impurities. Photocatalysis technology prevents pollutants from damaging the facade of your building as its surface is microscopically smooth, making it difficult for dirt particles to settle. Furthermore, the render is fast drying which prevents algae and fungi from forming, leaving your rendered facade looking clean and fresh for longer.