Choosing the right External Wall Insulation System

Have you thought about adding external wall insulation (EWI) to your building?  You’ve done the research to make sure your property is suitable and now you are ready to take the next step and decide on which EWI system is right for insulating your home.

Baumit has a few options to choose from, each with their own unique benefits to suit different projects depending on the type of building, the location, the substrate and any project specifications.  

Whether you are looking for flexibility and protection, or perhaps you are looking for an EWI system that offers excellent sound and fireproofing properties, Baumit has a system to suit all these needs, read on to find out more to help you with your decision making.


Before we dive in, let’s answer the question of what is the core component of an EWI system and why does this matter?

The core component of each Baumit external wall insulation system are the insulation boards which are rectangular boards available in various thicknesses and made from either EPS (expanded polystyrene), mineral wool or wood fibre. Each type of board has different properties and this is what distinguishes the systems from each other.  Which one is best for your project depends on the project brief and any legal requirements that need to be taken into account.  Read on as we discuss the benefits and differences of each Baumit EWI system.

The classic solution - Baumit StarSystem EPS 

Consisting of StarTherm EPS insulation boards, this is the most popular system because of it’s high thermal insulation property. EPS boards can achieve a good level of insulation at a smaller thickness than other insulation options, therefore a thinner layer of insulation is required to achieve the same thermal outcome.  Most installers will also agree that these systems are easier and quicker to install reducing labour costs.

StarSystem EPS Build Up

The all rounder - Baumit StarSystem Mineral  

This is a system for those with the requirement for excellent sound and fireproofing properties such as multi- story buildings, hospitals, schools, and local authority projects.  The reason for this is because of the fire resistance property of Mineral Wool EWI Slab that is the insulation board for the system.  For buildings over 3 stories, Mineral Wool is the only solution for insulation. Wood fibre insulation boards also have excellent sound proofing properties so the addition of Baumit StarSystem Mineral EWI system will also reduce any external noise from penetrating walls that were previously uninsulated.

StarSystem Mineral Build Up

The ecological alternative - Baumit StarSystem Nature 

This is the system for those who want to build with natural materials. The central component of this system is the Wood fibre insulation boards. As well as having good thermal insulation properties this system also improves sound insulation.

StarSystem Nature BuildUp

Here is a summary of the key properties and benefits of each of the  Baumit EWI Systems you can consider:

StarSystem EPS

  • BBA approved system
  • Flexibility and protection
  • Offers a broad range of solutions

StarSystem Mineral

  • BBA approved system
  • Fire resistant
  • Highly permeable

StarSystem Nature

  • Wood fibre natural insulation
  • Highly breathable
  • High heat storage capacity 

If you’re still not sure which system is best for you then take a look at a few case studies:

Baumit StarSystem EPS: Mountsorrell Drive 
Baumit StarSystem Mineral: South Cliff tower
Baumit StarSystem Nature: Pavilion in a Hayrack

If you’ve read this and you’re wondering if an external wall insulation is right for you, read about why you should consider external wall insulation.