Companies BH Keramiek, Energie-Positief and roof tile manufacturer Meyer-Holsen have collaborated to develop a sustainable white ceramic roof tile. The goal of this innovative product development is a significant reduction of the urban heat island effect, resulting in a more liveable climate for people and animals. White roof tiles provide a solution because they reflect up to 92% of the heat, and as an added benefit solar panels on these roofs generate higher yields.
Heat islands in the Netherlands:
Heat islands are small or larger areas, usually in cities, where the temperature is several degrees higher than other areas. The temperature differences can be as high as eight degrees Celsius. Such areas often include high-rise or other multi-storey buildings. There is very little vegetation, which means a dearth of shade and evaporative cooling, insufficient water and wind is present and the building materials, roofs and asphalt used are generally dark in colour. As a result of the heat island effect significant heat absorption takes place during the day and very little cooling occurs during the night. A reduction of this heating effect in these living areas will make them much more pleasant for people and animals, people will sleep better, labour productivity will increase and aggressive behaviour will diminish (source: www.hitte-eilanden.nl).
The effect of white:
To make the environment more liveable while also making buildings more energy efficient, BH Keramiek, Energie-Positief and roof tile manufacturer Meyer-Holsen have developed a special white ceramic roof tile. White roofing and other environmentally friendly products, such as sedum roof mats, already exist, but these choices are only suitable for flat roofs. A white roof tile is a good solution for pitched roofs and also works well in combination with solar panels. ‘A white roof tile offers a number of advantages,’ says Gideon Goudsmit, energy expert at Energie-Positief. ‘Because the heat is reflected, attic rooms and other spaces directly beneath the roof remain cooler, so in many cases air conditioning is no longer required. For larger buildings this also means that lower capacity cooling systems can be specified, resulting in a smaller price tag. Savings are also realized on the energy costs. The white roof tiles in combination with a solar array even boost the energy yield of the panels.’
Not just white:
An American study has concluded that a grey roof reflects 20% of the heat and is 38 °C warmer than the ambient temperature on a sunny afternoon. In the same situation a red roof reflects 35% of the heat and is 20 °C warmer, while a white roof reflects around 85% of heat and is just 5 °C warmer than the ambient temperature (source: www.heatisland.lbl.gov).
Sustainable Ivory White roof tiles:
Renowned roof tile manufacturer Meyer-Holsen has developed a ceramic roof tile with an Ivory White glaze colour. The glaze layer provides a durable, highly impermeable top layer. Dirt and moss adhere poorly to this layer, so the Ivory White ceramic roof tile retains its functional properties over time.
Three models are available: the flat Piano roof tile, the concave Vario roof tile and the Ravensberger flat roof (FD) tile. All the roof tiles are covered by a 40 year warranty. Meyer-Holsen produces the Ivory White colour on request for larger new build and renovation projects. For smaller projects the models are available in the colour Pearl White.
These white roof tiles have already been installed on a number of projects, such as the Polderhuis building in Amstelveen and an old, former pumping station in Nes aan de Amstel.