Energy renovation in Europe usually consists of replacing elderly windows with more energy-efficient types – equipped for instance with GRP composite frames. But for a more eye-catching reduction in heating bill the entire facade has to be renovated. And here it is necessary to think twice about what method to use.

Damp and inadequate drying out have caused large problems in the building industry in recent years. And when you energy-renovate with high-insulating materials you risk creating new condensation problems. Because a brick or concrete front wall will have difficulty drying out when it no longer receives heat from the construction behind it.

A sounder alternative technique is therefore attracting widespread attention: the "ventilated facade system". Dating from 1949, the Coat House in Kolding, Denmark, is a good example of how to construct a ventilated facade.

Coat House

Coat House was first wrapped in 300 mm insulating batts and then clad with facade planks made of GRP composite. At the same time the existing windows were replaced by new triple-glazed units fitted with GRP frames

Using this method means:

• Reduced condensation as there is continuous effective ventilation.
• Increased energy efficiency both summer and winter
• In winter the construction is dried out by the ventilation, thereby increasing the degree of insulation. In summer the warm air in the wall cavity rises and is exchanged with cooler air. This helps maintain a pleasant and comfortable indoor climate.
• Reduced noise from outside.
• The ventilated facade increases sound insulation and is therefore ideal for urban buildings – such as apartment blocks. Increased scope for personal design preference.

Coat House is clad with translucent GRP planks but many other materials can also be used.