Table of contents:
- Old roofs are particularly susceptible to storms
- New buildings are less sensitive
- After the storm: what to do when the damage is done?
- These roofs best withstand the storms
- Additional stability for existing buildings
Video: Wind and storm: This is how the roof becomes storm-proof
After hurricane "Burglind" the storm low "Friedrike": The year 2018 has started stormy. Hurricane gusts of up to 120 kilometers per hour were measured, particularly in the center and south of Germany, which caused damage to houses, cars and other objects. In such situations, the question arises: What makes a roof storm-proof?
The roof offers the largest storm attack surface in single-family houses. Oddly enough, the worst damage often occurs where the residents do not suspect it: on the side away from the wind. But why? Roof expert Jens Lehmann explains: The cause is the dangerous wind suction. From a speed of 50 to 60 kilometers per hour - this corresponds to strength 7 - the storm could generate a suction force per square meter of roof area, which corresponds to a train weight of 100 kilograms. The result: loose, loose and light roof coverings are lifted like a giant vacuum and whirled through the air. If the covering is missing, the wind also has an easy time with the underlying insulation. Even the smallest leaks can cause great damage: penetrating rain leads to permanent moisture damage and even mold.
Old roofs are particularly susceptible to storms
Roofs that are getting on in years or where the roof covering is no longer properly attached are particularly susceptible. Loose chimney surrounds, curved metal covers or broken and weathered asbestos panels offer easy points of attack. In addition to the risk of injury from flying parts, there is also the possibility that dangerous asbestos abrasion and fiber dust can get into the breathing air.
As a rule of thumb, if the roofing material used has reached its durability limit, homeowners should have their roof checked regularly by a specialist before the start of the winter and spring storms. Because if loose roofing material falls, possibly injuring people or damaging cars, the homeowner is liable within the framework of his obligation to ensure traffic safety. If you want to be on the safe side, renovate your roof before it shows the first signs of deterioration. A study by the Federal Technical Experts (BTE) indicates an average lifespan of between 25 and 40 years for aluminum, zinc sheet and fiber cement coverings, and between 40 and 50 years for concrete roof tiles and bricks. According to the BTE study, slate lasts more than 75 years.
New buildings are less sensitive
The roofs of younger houses that were built or renovated after March 1, 2011 are designed for higher wind speeds in accordance with the new wind suction safety regulations. The roofs of older properties are problematic, although the majority are very clear. Buildings that stand on hills, mountain tops, open spaces or on slopes are particularly vulnerable.
After the storm: what to do when the damage is done?
A residential building and household contents insurance covers, among other things, damage caused by storm, hail and lightning, the Federation of Insureds (BdV) informs.
If the storm covers the roof so that rain can penetrate and damage furniture, residential building insurance will replace damage to the house and everything that is permanently attached and damaged to the inside and outside of the house - such as the house electrics, heating systems or gutters. And if necessary, it takes over the costs of demolition and cleanup. Household insurance covers the damage to property and property that has arisen in the house or apartment, i.e. on all movable items such as furniture, clothing or supplies.
If you also want to protect yourself against floods, you must add an elementary damage insurance to your home and household insurance. It also covers damage caused by earthquakes, subsidence, landslides, avalanches, volcanic eruptions, backwater or snow pressure on or in the building.
At least wind force 8 is considered a storm. Anyone affected by storm damage should secure the house or apartment as quickly as possible against further damage. Because the policyholder has a duty to mitigate damage. This means that, for example, broken windows must be sealed or household items in the basement must be brought to safety as far as possible so that the damage does not increase. However, the insurer also covers these preventive protection costs. However, your own safety always has priority.
In any case, the insurer must be informed immediately of the occurrence of a claim in the event of a claim. For documentation purposes, photos of the damage to the building and household items should be taken and an exact list of the damaged objects should be created.
Slate is considered a stable roof covering.
Photo: Rathscheck Schiefer
These roofs best withstand the storms
Experts assume that the frequency of storms will increase in the future. That is also why you are well advised if you are already thinking about the right type of roof when planning the construction. Flat roofs, for example, are more susceptible to storm damage than steep roofs. The latter offer more resistance to the wind due to their design. Flat roofs can look like a sail in a storm. The suction forces can become so strong that the entire roof structure lifts off.
Pitched roofs are less susceptible due to their aerodynamic properties: the wind forces can break at the ridge, the suction forces are weakened on the side that is not inclined to the wind. As a result, the damage in storms is less here than in flat roofs.
In addition to the construction method, the roofing material also has a major impact on the storm resistance of the roof: roofs made of slate and titanium zinc can also withstand greater winds. Since each slate plate is attached to a formwork with three nails or screws, the wind has practically no surface to attack - the roof becomes particularly stable. Hard roofing with roof tiles and roof tiles is usually relatively storm-proof.
Additional stability for existing buildings
But storm safety can not only be improved in new buildings. Precautionary measures also make sense in existing buildings. If you install storm clips, for example, you minimize the effect of the wind suction and prevent the roof tiles from slipping. The number of clips that must be used to secure a roof mainly depends on the shape and slope of the roof and the covering material.
The geographic location of the house must also be taken into account when planning wind protection measures. The coastal regions are particularly at risk of storms. In southern Germany, with the exception of the Alpine region, things are a bit quieter. Depending on the local wind load, it is recommended to secure every third, second or even every single roof tile with storm clips.
Popular by topic
Roof insulation increases living comfort under the slope and reduces heating costs. You can find out about the different ways to insulate the roof here
Building a roof terrace is not an easy task even for experienced do-it-yourselfers. You can find out everything about construction and design here
The roof is already completely green? Then you should quickly clean the roof tiles. We explain how to do it
Roofing felt is not only used to seal flat roofs. Saddle and pitched roofs also have an additional seal. What are the advantages of roofing felt and how to lay it yourself:
Listen to the heart! Together with metal bars, they play a relaxing melody