Baumit OpenSystem: Breathable External Wall Insulation

Baumit OpenSystem:
Breathable External Wall Insulation

Whether you are building a new home or refurbishing an old one, Baumit OpenSystem is the best option for breathable wall insulation. All components contain vapour-permeable insulation and thus allow the walls to breathe. This creates optimal living conditions whether in summer or winter. 

The Baumit OpenSystem uses EPS wall insulation boards containing numerous holes of 2 to 3 mm diameter. These ensure high vapour permeability and enable water vapour to be released externally. The OpenSystem consists of 99% air and only a small proportion of EPS render, which, in turn, requires very little energy to produce, therefore resulting in low environmental impact.

  • Unique OpenAir technology
  • Breathable insulation 
  • Cosy healthy climate

Comfort at all times

Everyone understands the discomfort of a home that’s the wrong temperature. Whether it’s stiflingly hot in summer or freezing cold in winter, poor temperature control can be handled by effective insulation.

In addition to the temperature, an important, and often overlooked, factor in enabling a comfortable living climate is relative humidity. High humidity can not only lead to feelings of discomfort, but a build-up of water vapour from high humidity can cause mould and mildew to thrive. Repeatedly breathing this in can cause sickness among residents and frequent users of a building.

With typical indoor temperatures of between 19 and 22 °C, humidity should be between 30% and 60%. Therefore, approximately 10 litres of water vapour per household per day needs to be diffused to the outside. Low-quality external wall insulation won’t allow the home to breathe, causing water vapour to build up. 

The Baumit OpenSystem, however, has made permeability a key factor. The expanded polystyrene OpenTherm releases water vapour through minuscule perforations, without sacrificing thermal insulation. With its vapour-permeable insulation and high breathability, the Baumit OpenSystem ensures a comfortable indoor climate. 

But it isn’t just the insulation layer itself that aids breathability. All parts of the OpenSystem work together to create a better household climate. The Baumit StarContact White adhesive and basecoat reinforcing render is vapour-permeable, and together with the OpenTherm enables water vapour to pass efficiently through the external wall insulation system.

A façade that lasts

This polystyrene external wall insulation has some notable features that help buildings to not only perform well, but also to look good for many years to come. 

The Baumit PremiumPrimer is a ready-to-use primer that prepares the surface before application, regulating absorption for a higher quality bond. The new filler grain creates a base layer that not only improves application, but will help give a smooth surface to the primer, even on tricky substrates.

The system is finished with the Baumit StarTop, a weatherproof topcoat render that is quick-drying even in damp conditions. Offering improved protection against algae and mould, this final facade layer dries to a smooth and attractive finish. Thanks to the easy application and silicon binder, this is a finish you can trust to remain appealing and functional. 

The Baumit OpenSystem combines the best fixing technology, breathable insulation boards, and high-performance primers, adhesives, and topcoats to help create a building that will last for decades to come.

Benefits of our external wall insulation

  • Complete wall build-up from a long-lasting and durable polystyrene external wall insulation system.
  • Air is at the heart of this breathable insulation system, and understanding how air passes through materials is how this exceptional design was created. Because of this, the OpenSystem has a low environmental impact.
  • Miniscule holes are used to create highly breathable insulation boards, improving the release of water vapours from the house, without adding extra cost for improved ventilation.
  • Vapour permeable insulation diffuses more water vapour outside the home, preventing a build-up of condensation. Not only is this more comfortable to live in, but it also reduces the risk of mould.
  • Ensures a comfortable indoor living climate thanks to controlled humidity and temperature.
  • The combination of high breathability and vapour permeable insulation keeps temperatures regulated, for comfortable living conditions in both the summer and winter.
  • The attractive and smooth surface of the Baumit external wall insulation system builds to an excellent finish for an insulation option that’s both appealing and high-performance.
  • Polystyrene external wall insulation uses the best fixing technology, for a durable build that can stand the test of time.
  • Easy application ensures that you can use the Baumit System on various substrates, and build to an even and hard-working finish with minimal effort.
  • Each layer of the system works together, enforcing a bond and growing the thermal insulation and breathability. 

Our External Wall Insulation System

Every element in the OpenSystem has been specially developed, tested, and improved upon over time to be as efficient as possible. Each element performs exceptionally on its own, but when working as a system, they come together to create external wall insulation that you can trust in.

The heart of the system is the insulation boards. The polystyrene-based board features a patented system of holes to ensure rapid diffusion of water vapour.

However, even with ‘holes’ the EPS provides the same level of thermal insulation as regular insulating boards. And with the OpenSystem primers, basecoat, and topcoat working alongside, these insulation boards are able to regulate temperature and humidity, for a happy home environment.

System components

Open System

Base- new masonry or original base
1. Final Topcoat - Baumit StarTop  is a highly weatherproof topcoat render, complete with silicon binder and a new functional filler, providing the building with a quick-drying finished façade surface in damp weather conditions.  
2. Primer - Baumit PremiumPrimer is a ready-to-use primer for synthetic and mineral decorative finishes. It has high covering power and regulates absorption.  
3. Basecoat - Baumit StarContact White is a vapour-permeable, adhesive and basecoat reinforcing render. 
4. Reinforcement - Baumit StarTex is warp-resistant and alkali-resistant glass fibre mesh that is used to produce a reinforced mortar layer on torn old rendered facades.  
5. Insulation - Baumit OpenTherm is a highly breathable, thermal insulation made from expanded polystyrene. The insulation is specially designed for brickwork and similarly breathable masonry.  
6. Adhesive - Baumit StarContact White is a vapour-permeable, adhesive and basecoat reinforcing render. 
7. Fixing - Baumit StarTrack adhesive anchors bring many advantages. No thermal bridges and allows good adhesion without additional fixing.