Heavy rainfall is becoming increasingly frequent and can cause considerable damage to residential buildings. The Wohnen im Eigentum (WiE) consumer protection association explains what protective measures property owners can take and which insurance is advisable. As jointly owned property is usually affected, measures of this kind must be approved at an owners’ meeting in condominium owners’ associations (WEGs).
Suitable structural measures and organisational precautions help to minimise damage caused by heavy rainfall. The following overview shows which protective measures may be useful and what condominium owners’ associations need to consider when implementing them.
Backflow valves or a lifting station
If the sewer system can no longer cope with the volume of water during heavy rainfall, property owners must expect water to back up into the building’s connection pipes. Basement flats and basement rooms (that is, rooms below street level) are particularly at risk during heavy rainfall. If water backs up in the sewer network, wastewater can be forced up into the building through baths, showers and toilets.
Backflow valves provide protection. They prevent water from flowing from the sewer system into the building’s wastewater pipes. However, the Consumer Advice Centre of North Rhine-Westphalia reports that they are often installed in the wrong place. It is therefore important to seek advice from a specialist plumbing company or water engineering consultancy on exactly where the backflow protection should be fitted. If the drainage points do not slope towards the sewer, a wastewater lifting station is required. This uses a pump to carry wastewater out of the building.
Regular maintenance is mandatory
Backflow valves and lifting stations must be serviced regularly; otherwise, owners may risk losing their insurance cover, if they have it. Maintenance should therefore be documented carefully.
Protect basement windows and doors, light wells and gates
Basement windows, external basement doors and light wells are also particularly vulnerable areas, as water can easily enter the building through them.
Where possible, basement windows should be installed so that they open outwards. Installing special pressure-resistant, watertight windows in the basement may also be advisable. These can withstand the high water pressure that may arise during flooding and heavy rainfall.
Mobile flood protection systems, such as flood barriers, offer another possible form of protection. These mobile dam systems can be installed quickly and are available in various designs. They can also be fitted to protect garage doors and light wells, for example.
Keep an eye on the underground car park
The flood protection systems mentioned above can also protect large areas of underground car parks. Larger condominium owners’ associations, in particular, often have an underground car park and should include it in their preventive measures. “Flooding or heavy rainfall in an underground car park can be expensive for condominium owners’ associations, not least because of damage to vehicles parked there,” says WiE board member Dr Sandra von Möller.
Patios and balconies
Large volumes of water can also overwhelm drains on balconies and patios. Possible causes include a missing or inadequate slope, poor waterproofing or blocked drains. Drains should be cleaned regularly. Owners should seek expert advice on what other measures may be appropriate to prevent water from entering the living area during heavy rainfall or damaging the building fabric.
Clean gutters and fit leaf guards
Gutters should be cleaned regularly; otherwise, water can run off uncontrollably during heavy rainfall and damage the plinth, roof or façade. Leaf guards, which can be clipped into the gutter, for example, can help.
Check roof windows for leaks
Anyone with older roof windows should check that they are still watertight. If they are not, the windows can be resealed or replaced with modern new ones.
Advice from a specialist company is important
The following applies to all protective measures: property owners should first seek advice from a specialist company to determine which structural measures are best suited to the particular building. Local conditions should also be taken into account. The “Hochwasser-Check” provided by the German Insurance Association allows property owners to assess their individual exposure to heavy rainfall and river flooding.
Damage is covered only by natural hazards insurance
Property owners should also review their insurance cover. Buildings insurance and household contents insurance do not cover damage to residential buildings caused by heavy rainfall. Owners must take out additional natural hazards insurance and ensure that damage caused by heavy rainfall is explicitly included. Certain types of damage caused by backed-up water may, for example, be excluded from cover. This can vary depending on the insurer or policy. “Owners should therefore always read the small print before taking out insurance,” advises WiE board member Dr Sandra von Möller.
WEGs must pass a resolution
“Condominium owners’ associations must pass a resolution if they wish to implement measures to protect the building against heavy rainfall and flooding. This is because the measures generally affect jointly owned property, and the condominium owners decide on such matters together at the owners’ meeting,” explains Dr Sandra von Möller. “This also applies to work on windows because, contrary to the wording of many declarations of division in WEGs, windows are also necessarily jointly owned property.”