Storms with enormous amounts of precipitation have massively increased in intensity in recent years. Heavy rainfall on grassland of up to 5 litres of rainwater per m2 creates raging rivers and overflows canals within 5 minutes. These natural phenomena are not limited to classic flood areas and therefore catch residents completely unprepared.

The rate at which water runs off depends on the slope, the ground cover and the surface conditions of the subsoil. The decisive factor for the damage potential is how well buildings are protected against water ingress, e.g. by protective measures such as approach steps.

An overview of the risk and exposure of your building or property is provided by the:
digital hazard map HORA

Heavy rain

Preventive Measure

Canals can no longer hold enormous amounts of water and roads serve as tributaries. Higher flow velocities sweep away small debris and soil, causing blockages. Drains and outlets become blocked and water and muddy streets subsequently flood buildings.

Work on the roof is evidently one of the most dangerous activities.
PERSONAL PROTECTION IS THE TOP PRIORITY!

• At low water levels, entry points such as doors, windows, garage entrances and light wells should be sealed with sandbags.
• Shuttering panels, which are inserted into pre-mounted guide rails, also serve this purpose at higher water levels.
• Acquire a submersible pump
• Raise moisture-sensitive inventory or electrical appliances in basement rooms (stilts).

• Regular cleaning of gutters and drains.
• Remove alluvial materials in front of drains and gutters.
• Remove accumulations (washed-up soil) in front of protective walls.

• Surrounding terrain must be taken into account during planning or changes must be taken into account without fail.
• Provide light wells and other components leading into the interior of the building with a step. The height of the step depends on the maximum backflow level and must exceed it.
• Seal windows and doors on the ground floor and in the basement in such a way that, if the windows and doors are tight, the adjacent building components can also withstand the water load.
• Drainage systems of light wells and basements can be flooded by a backwater of the drainage pipes (drainages). Therefore, these must be planned up to the point of discharge (meadow, stream, channel, etc.) to prevent a reverse flow direction in the pipe.
• If property enclosures are designed for surface water protection, consideration must be given to protecting downstream properties.
• Check valves should be provided in domestic sewers to prevent backwater from entering from the main sewer.
• Electrical installations in basements should be placed in an elevated position, if possible.
• When installing underground tanks, the uplift forces due to variable groundwater situations must be considered.
• Provide a pump shaft in the basement.
• Possible uncontrolled roof water runoff can cause problems on façade elements > Check after the event.

Studies show that hail catastrophes are occurring more often and more intensively and are spreading, especially over previously known regions. An overview of whether your building is in a danger zone or not is provided by the hail zoning map for Austria. It shows whether you are in a hail zone or in which zone you are planning to build. Available download here

Hail

Preventive Measure

Damage can vary: from small dents and colour changes, which are a visual impairment, to punctures or destruction of a building shell. Subsequently, rainwater can penetrate again and cause further damage.

Decisive factors for the load on building components during hailstorms are the size of the hail, the impact speed and the impact angle. The table below shows the comparison between TORRO classes and HW classes:

PERSONAL SAFETY IS THE TOP PRIORITY!
Never leave the protected area due to the risk of injury!

• Store a sufficient quantity of tarpaulins as a precaution.
• Provide catchment facilities for penetrating water (buckets, blankets).
• In the event of a hail warning, close windows and doors and lock gates properly.

• Check roof drains, outlets and inlets regularly and keep them clear.
• Replace plastic components in good time, as hail resistance decreases over time.
• Check the roof covering regularly and replace damaged elements.
• Increase the thickness of the outer panes of glass.
• It is possible to cover glass domes with hail protection grids.
• Maintain existing wood protection on an ongoing basis.

Even during the planning phase, basic factors can be taken into account to prevent or minimise potential damage caused by hailstorms to roof coverings, façades and the like. The choice of location and materials play a decisive role.

Type, resistance, ageing effect, roof pitch, substructure of the roof covering

Building materials
Component thickness, elasticity of the components

• For new builds and renovations, pay attention to the resistance of the components.
• These are listed in the hail register (www.hagelregister.at).
• A sub-roof (cold roof) protects against water ingress and thus against major consequential damage.
• Roof overhangs also provide protection for the façade.
  • In the case of composite thermal insulation façades, which are increasingly becoming the exterior walls in the course of thermal refurbishment, there are systems with different levels of resistance.
  • For skylight domes and other exposed components that are sensitive to hail, it is advisable to install hail protection grilles.
  • Wooden windows and doors can also be retrofitted with aluminium cladding.
  • Install emergency overflows on terraces, loggias and flat roofs.
  • Roof flat roofs with gravel if structurally possible.

The effect of wind on buildings depends to a large extent on the location, the altitude, the shape of the terrain (slope, hilltop, etc.) and the surrounding vegetation. The height and shape of the building, the position of the openings and the state of preservation of the building are also decisive.

An overview of the hazard and exposure of your building or property is shown in the:
digital hazard map HORA

Storm

Preventive Measure

Damage is often caused not only by wind pressure, but mainly by suction forces. Individual components (roof, façade, etc.) cannot withstand the acting wind forces. The roof structure collapses partially or completely, or load-bearing parts of the building structure fail, causing it to collapse.

PERSONAL PROTECTION IS THE TOP PRIORITY!

• Plan a rescue chain in case of an emergency, because only trained persons should carry out safety measures on the roof, e.g. fire brigade, master builder, roofer, master carpenter, etc.
• Use modern weather forecast models (e.g. weather warning services via SMS and Internet).
• Link electronic wind monitor control with weather warning services.
• Stock tarpaulins and fixing materials.
• Move or secure movable objects (garden furniture, playground equipment, etc.).
• Retract awnings and blinds before the storm starts.
• Close windows, doors, gates, shutters and armoured blinds.
• Keep trees at a sufficient distance from the objects.

• Check and maintain the building envelope: roofing, façade, doors, gates, windows, etc.
• Check that flat roofs are adequately covered with gravel.
• Check roof structure for severe deformation, scorching and breakage.
• Retrofit missing elements: storm clamps, anchoring possibilities for securing persons on the roof, etc.
• Replace damaged components in good time.

• Protection starts with choosing the right building location.
• A low building height is advantageous.
• Align the roof shape and location with the main wind direction.
• A sub-roof (cold roof) protects against water ingress and thus against major consequential damage.
• Consider roof reinforcements and additional anchoring when retrofitting solar and photovoltaic systems.
• Ensure correct installation of building products according to the manufacturer’s instructions.
• Add storm clips at problem areas.
• Form the soffit of eaves.
• Attach fasteners and reinforcements to gate latches.
• Obtain manufacturer’s wind resistance data for components such as roller shutters and venetian blinds.

PERSONAL PROTECTION IS THE TOP PRIORITY!

• There is only one way to protect yourself effectively from a direct lightning strike – the lightning protection system.
• Plan the rescue chain for an emergency, because only trained persons should carry out safety measures on the roof, e.g. fire brigade, master builder, roofer, master carpenter,…
• Do not succumb to the misconception that lightning always strikes the highest building in its target area.
• A lightning protection system does not increase the probability of a lightning strike.
• If no surge protection devices are available, unplug appliances from the mains sockets.
• Provide fall protection.
• Work on the roof is evidently one of the most dangerous activities.

• Regular, professional maintenance of the lightning protection system.
• 3 to 5 years for farms and business premises.
• 10 years for small buildings (detached houses).
• Check your surge protection devices after every thunderstorm to ensure they are in working order.
• Retrofit missing elements, parts of the lightning protection system, anchoring possibilities for personal safety.
• Replace damaged components of the lightning protection system in good time.
• Visual inspection after storms and winter with regard to damage to the air-termination systems on the roof.

• Foundation earth electrodes for the lightning protection system must be provided for during the planning stage so that cost-effective retrofitting is possible at any time.
• A prerequisite is that the lightning protection system is professionally planned, installed and maintained.
• To prevent the consequences of an indirect lightning strike, surge protection devices should be provided for sensitive electrical equipment (e.g. heating system, photovoltaics, milking systems, home cinema, computers, bus controls for building services, …).
• In the meantime, integrated lightning protection systems are on the market that can also be used as fall protection.

The snow load acting on roof structures depends on the amount of snow, the change of frost and thaw, the wind conditions as well as the location and altitude of the property.

An overview of the hazard and load on your building or property is shown in the:
digital hazard map HORA

Snow

Preventive Measure

Excessive snow loads can cause damage to individual building components or even the collapse of entire roof structures. In addition, there is a risk that sliding snow will destroy underlying building components. Ice formation leads to water ingress and consequential moisture damage can occur.

PERSONAL PROTECTION IS THE TOP PRIORITY!

• Plan the rescue chain for an emergency; only trained persons should carry out safety measures on the roof, e.g. fire brigade, master builder, roofer, master carpenter, etc.
• Use modern weather forecast models (e.g. weather warning services via SMS and Internet).
• Stock tarpaulins and material for shelter and support.

• Regularly check roof structures for deformation, scorching and breakage.
• Retrofit anchoring facilities to secure people to the roof.

Snow clearance plan:

• In case of danger to persons, arrange for the buildings to be cleared.
• Start clearing in good time in the hazardous situation. This measure is the responsibility of the owner of the property.
• Only shovel off in a secured manner!
• Shovel the roof evenly, leave frozen snow on the roof.
• Pay attention to roof installations such as skylights, light panels, skylight domes, etc.
• Chimneys may already be damaged by the snow pressure.
• Remove accumulated, cleared snow from the side walls to avoid one-sided horizontal pressure on the walls.
• Observe distances to power lines.

• A sub-roof (cold roof) protects against water ingress and thus against consequential damage.
• Consider roof reinforcements and additional anchoring when retrofitting solar and photovoltaic systems (formation of snow cornices, etc.).
• Sufficiently dimension roof projections.
• When retrofitting snow catchers, be sure to obtain advice from a specialist company.

ALWAYS ENSURE THAT NEW BUILDINGS AND RENOVATIONS ARE CARRIED OUT IN ACCORDANCE WITH STANDARDS, THE STATE OF THE ART AND THE MANUFACTURER’S SPECIFICATIONS.