A Leak Sensor After Water Got Into The House
During heavy rain, one of the light shafts at our basement windows filled faster than it could drain. At some point the pressure was too much for the window and water came inside.
We were lucky twice over: someone noticed it straight away, and the rain stopped soon after. But it was a clear warning that a longer downpour could flood the cellar.
Making the shafts and windows properly watertight is the real fix and will take time. As an interim measure I installed a Zigbee leak sensor — a small battery device that raises an alarm as soon as it feels water.