Wintergardens and glass canopies don’t just look good – they also provide shelter. But extreme weather conditions such as those we experienced this February place them under a lot of strain, and snow and ice are heavy loads for a glass roof to bear. When subjected to such conditions, cheap structures can often give, leading to a risk of severe or even fatal injury for those beneath them. But providers of high-quality roofs and canopies don’t let things get that bad, and always make sure that their plans incorporate all the elements required to build a safe roof that can withstand anything winter throws at it.
A bone-chilling cold, mountains of snow on the roofs and by the road – the cold snap that hit northern and central Germany this February was sudden and severe. When the snow comes down heavy, the loads that roofs have to bear quickly rocket into the hundreds of kilos. Even just 10 cm of powder snow results in around 10 kg of weight per square metre. And the same effect can be achieved by just 2.5 cm of wet snow or 1 cm of ice. When you consider how common it was to see 30 to 50 cm of snow just a few weeks ago, those numbers become even more concerning.
“In extreme weather conditions like these, the strain placed on roofs is enormous,” says Mario Altehoff, Product Manager at Solarlux. “As such, there are many different factors a manufacturer of high-quality wintergardens and glass canopies needs to consider when planning and building their products.” Solarlux is a family-owned company based in Melle, north-west Germany, that specialises in glazed extensions and facade solutions. Whenever they start a new project, the most important question they ask themselves is where it is going to be built. The “snow load zone map” is an essential tool in this process. The map allocates each region to one of five zones based on its average snow load. Large areas of Germany are in Zone 2, which means that the roofs there need to be able to withstand a load of at least 0.85 kN per square metre depending on their altitude – equivalent to a weight of 85 kilograms.
Good providers also cater to extreme weather conditions
However, during extreme cold snaps like that experienced in parts of Germany this February, the snow load can build up to far above the average. This applies particularly to regions in the north German lowlands. In order to ensure that there is no risk of roofs collapsing and killing the occupants of buildings, glass canopies and wintergardens needs to be built to withstand even the harshest of winters.
“This is where the wheat is separated from the chaff,” says Altehoff. “Not every manufacturer accounts for extreme weather conditions like those we sometimes see in the lowlands of northern Germany.” And there’s another problem, too: “Some providers of flat-pack glass canopies for customers to build themselves even include a disclaimer in their installation instructions and user manuals to say that you shouldn’t stand under the extension when it’s snowing – or even when it’s raining heavily. That’s precisely because they don’t offer the requisite stability.”
Decades of reliability
Manufacturers of good systems also take the altitude local wind load and structure of the house into consideration in their designs. What is the incline of the roof? Does the customer want the wintergarden at their gable end or on the eaves side? Plans for structures built onto the gable end need to account for heavier snow drifts, while the risk of sudden strain focused on specific points due to falling snow is more of an issue for extensions on the eaves side of the house. The amount of force this falling snow exerts also varies depending on the distance between the roof of the house and the top edge of the glass canopy. On top of this, snow drifts can also be a problem on the eaves side, and strong winds in coastal areas can put roofs under even more strain than snow.
Manufacturers of high-quality extensions provide conscientious advice, are careful in their planning, and account for all the necessary safety factors in their construction. This information then helps them to calculate the required thickness of the glass and decide what type of construction to use based on the structural requirements. Last but not least, they employ highly trained and experienced staff to ensure that every aspect of the construction is completed to the highest professional standards. This gives their customers reliable wintergardens and glass canopies that will hold off the snow and provide decades of enjoyment for many winters to come.