Wall and façade insulation

Why is external wall insulation needed?

Although external wall insulation is mainly associated with saving energy, it also affects comfort in the home and the well-being and health of its occupants.

Buildings constructed today to new standards have much better thermal performance. Even so, depending on the material used for their walls, they often need additional insulation. All older buildings need their existing external or internal walls insulated, or improvements to insulation installed several years ago. Regulations and standards have changed recently: a few years ago, insulation thicknesses of 5-6 cm were standard. Today, standard thicknesses are 10-12 cm.

Choosing the right insulation material and thickness for internal or external walls is very important. Expanded polystyrene, glass wool and extruded polystyrene are recommended for external wall insulation. Correct installation is also crucial to performance. Any inconsistencies in the insulation layer and any thermal bridges are places where moisture levels are likely to rise, leading to mould and fungal growth.

Choosing an insulation material: expanded polystyrene, mineral wool or extruded polystyrene?

The insulation material should be selected at the design stage. Because of fire safety regulations, mineral wool should only be used on tall buildings (above 25 m). Mineral wool is completely non-combustible, but costs more than expanded polystyrene (2-2,5 times as much). Some manufacturers of materials for single-leaf walls recommend insulating them with mineral wool because of its low water vapour diffusion resistance factor (around 1). In other cases, the choice of material for insulating external or internal walls depends mainly on the client's budget.

You can read about mineral glass wool insulation rolls and slabs in the Insulation, mineral wool section.

Expanded polystyrene, also known as EPS, consists of air-filled beads. Air makes up no less than 98% of its total volume. The air in each cell cannot move, which gives the material good thermal insulation properties.

Advantages of expanded polystyrene insulation:

• very good insulation properties at low temperatures and in highly humid environments; expanded polystyrene insulation can be installed at any time of year, regardless of air humidity and temperature;
• natural water repellency – expanded polystyrene does not absorb water;
• lightweight boards, making transport to the building site and installation easier;
• long service life (resistance to ageing);
• resistance to bacteria, mould and fungi;
• low water vapour permeability;
• suitable for both new roofs and roof refurbishment.

The expanded polystyrene used in construction is self-extinguishing: it burns when directly exposed to fire but goes out once the fire is removed. Its ease of working is a clear advantage. Expanded polystyrene produces no dust during installation, is completely harmless to health, does not cause allergies and does not irritate the respiratory tract.

Extruded polystyrene (XPS) products are now available on the market and outperform expanded polystyrene in many respects.

Extruded polystyrene is made by adding a foaming agent to polystyrene and pressing it to the required thickness. It is harder than expanded polystyrene and has better thermal insulation properties. It also differs from expanded polystyrene in being coloured. XPS polystyrene:

• is highly resistant to moisture and water,
• resists compression and deformation,
• has an exceptionally low thermal conductivity,

which makes it worth using to insulate below-ground parts of buildings and plinths. Rigid XPS boards prevent heat loss and also protect the waterproofing layer.

External wall insulation manufacturers

Leading insulation manufacturers include:

• Swisspor
• Ursa
• Isover

All the external wall insulation we offer comes with a long-term warranty. Ambit's specialists will be happy to help you choose the best solution for your home. Our experts can explain everything and answer your questions. Every customer matters to us, and we are happy to help everyone choose the products they need.