Those who live in regions where the rains are devastating all have their little tricks, when the water rises, to protect their homes. They raise their furniture, and seal the doors as best they can, with boards, metal plates… Or even sandbags. And they mop up, with everything that comes to hand, if the water manages to enter, despite their efforts. The Perpignan company Flowstop has developed an innovative device, capable, it assures, of keeping a house dry in the event of intense floods: this start-up has invented inflatable anti-flood barriers, which adapt to any which openings, and prevent water from passing through.
This device, patented and awarded at the last Lépine Competition, is intended for individuals, municipalities or businesses. Olivier Guillou, the founder of Flowstop, had this idea in 2015… while observing the inflatable stand-up paddle, which he had just purchased. “There had been deadly floods in the Alpes-Maritimes,” the entrepreneur confided to 20 minutes. I was asked if we couldn’t divert the use of the material used to make my stand-up paddle to combat flooding. »
Custom-made inflatable cofferdams, so that nothing gets through
After two and a half years of development, Olivier Guillou, supported by his partner Bertrand Sylvestre, managed to develop a cofferdam, an anti-flood barrier, unique on the market: light, easy to handle, install and store, inflatable in one to four minutes, and composed of two internal cushions, this device protects houses from floods. 100%… Or almost. “100% waterproofing does not exist at the level of cofferdams,” confides Olivier Guillou. However, we tested the device on a canal, on a highway. Over eight days, out of 50 m3 of water retained, only six liters passed to the other side. It’s infinitely little. That’s the equivalent of two mops. But looking for 100% waterproofness is my obsession. »
And so that nothing happens, Flowstop sells custom-made cofferdams, depending on the width of the access that customers want to protect. “In France, all doors are normally 90 centimeters wide,” explains the entrepreneur. But the frame, around the door, can be 93, 96… We can also have restored an old barn, with walls that are not really square… There are plenty of configurations. We therefore manufacture our devices on demand, tailor-made. Of course, we have identified some standard sizes, such as for 2.40 m garage doors, which we design in advance. »
“The prize in the Lépine competition was an incredible sounding board”
And, with the worrying recurrence of stormy episodes in France, particularly in the southern departments, Flowstop is attractive: in fourteen months, the company has sold 1,200 inflatable cofferdams. Around 600 euros for a traditional door, and around 1,200 euros for a garage door. “The prize at the Lépine Competition was an incredible sounding board for the media, and real credibility,” confides Olivier Guillou. We have equipped EDF nuclear power plants. We worked with Vinci or with Carrefour. And among individuals, the feedback is also very positive. I received a video by SMS from a gentleman from Perpignan, about a month ago, at 11:30 p.m., during a big storm. He said to me “Thank you, this is the first time my laundry room hasn’t flooded!” »
But Flowstop is also attractive abroad: the company has sent inflatable cofferdams to Germany, Belgium, Luxembourg, the United States, Canada, South Africa and Australia. It must be said that around 1.81 billion inhabitants, 23% of the world population, are exposed to centennial floods of more than 15 centimeters, according to a study, published in 2022 in the scientific journal Nature Communications.