For Owners

Flooding and heavy rain: how best to protect yourself

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October 2021

Waterproof windows, backwater valves and cisterns – there are numerous tips and tricks that can help you keep high water and heavy rain from entering your home from all sides. Although it is rarely possible to prevent damage altogether, it is by all means possible to keep it to a minimum. Find out here how to accomplish that and what are proven remedies.

Location is key – safeguarding your home from the outside

A sensible way to start is by inspecting your piece of property. If your house is located on a slope, surrounding walls and embankments can divert the water so that it bypasses your own property. When installing these, however, you must take care to place them in such a manner that they do not divert the water onto the adjacent property, thereby putting it at risk. Another way to deflect water is to install extra roofs. A roof above the cellar entrance ensures that the water is captured and that a short downpour will not penetrate the house. You may also employ a cistern – with the added benefit that you get to put the harvested rainwater to good use later on.

Not every window is the same

Basement windows are a notorious weak point. Of key importance for optimal waterproofing is the question whether the window is fully below the surface level or whether it could be completely submerged. If the window is only below the surface up to its mid-section, it may suffice to stuff the casing with sand bags or polymer bags to prevent a direct water ingress. By contrast, windows located below the surface level should be insulated with acrylic or magnetic bulkheads, sealing the gap between the frame and the reveal of the window. However, owners need to bear in mind that ageing masonry around the reveal may also become water-permeable. In this case, you need to renovate the masonry. While at it, the owner should seize the opportunity to test the water pressure that the water will sustain, which could make the replacement of the entire window preferable to waterproofing the old one. Particular attention should also be paid to light wells. Here is why: If the light well is water tight, it will keep water from even reaching the window.

Basements are the biggest issue

What makes basements particularly susceptible to flooding, apart from leaky basement windows, are overflowing sewers. During heavy rainfall or floods, gutters may soon reach capacity while public retention basin can fill up quickly. This may cause run-off water to back up into basements. To prevent this from happening, you could install a floor back-up valve – normally at a cost of 500 to 1,500 euros. Another option is to equip pump sumps in the basement with submersible pumps. Whenever water enters the basement, the pump will automatically spring into action. Homeowners should also check heating systems from time to time. Water pressure can cause ageing oil-fired heating system and their piping to fail eventually. If push comes to shove, it can actually make sense to flood the basement with clean water. Of course, this should only be done as a last resort, meaning when the flooding of the basement has become inevitable. The advantage of pre-emptive flooding with clean water is to limit the damage of polluted water to building parts.

Whatever else you do, buy insurance against damage by natural forces

Apart from the structural safeguards you may put in place, it is sensible to take out an insurance against damage by natural forces. It will insure you against damage caused by natural hazards like heavy rains, flooding, high water, snow pressure, avalanches, subsidence, earthquakes and volcanic eruptions. However, this type of insurance can be taken out only as an add-on to a residential building or household contents insurance policy. While the former covers the costs of repairs and drainage, where required, the latter insures all of your fixtures and furniture and will cover the replacement costs. When buying such a policy, be sure you know the current value of your home. Ultimately, however, protecting life and limb should have chief priority. Aside from any waterproofing you may undertake, your flood control plan should include alternative lighting and cooking equipment.

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