Humidity sensor/hygrometer to insert in cavity wall?

airmark

We had a problem with a water leak inside a cavity wall that caused a lot of damage to the floors before we even detected it. We (think we) sorted it out, but in case it happens again I was thinking of having a humidity sensor inside the cavity (or more likely behind the plasterboard if it can still give good measures), so that I monitor the moisture levels and be alerted if they increase.
It would be nice to integrate with the Fibaro Home Center 2 that I already have. However this is not a requirement or priority, the important thing is to find something that works well.
Any advice or recommendations would be appreciated.

airmark

Even though I started looking at zwave sensors, I found more options of standalone products at much lower prices especially if I want more sensors (I would like 2 or 3 actually)
These stands out:
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        ORIA Digital Thermometer Hygrometer with 3 Sensor, Indoor/Outdoor Humidity Meter Temperature Monitor, Wireless Weather Station with Backlight, Comfort Icon, Arrow Trends for Temp and humidity for Home: Amazon.co.uk: Kitchen & Home                                                                                                        ORIA Digital Thermometer Hygrometer with 3 Sensor, Indoor/Outdoor Humidity Meter Temperature Monitor, Wireless Weather Station with Backlight, Comfort Icon, Arrow Trends for Temp and humidity for Home: Amazon.co.uk: Kitchen & Home                                                                                                                                                                                                        www.amazon.co.uk                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        ThermoPro TP65 Digital Wireless Hygrometer Indoor Outdoor Thermometer Wireless Temperature and Humidity Monitor with Jumbo Touchscreen and Backlight Humidity Gauge, 200ft/60m Range: Amazon.co.uk: Kitchen & Home                                                                                                        Free delivery and returns on eligible orders. Buy ThermoPro TP65 Digital Wireless Hygrometer Indoor Outdoor Thermometer Wireless Temperature and Humidity Monitor with Jumbo Touchscreen and Backlight Humidity Gauge, 200ft/60m Range at Amazon UK.                                                                                                                                                                                                        www.amazon.co.uk                                                                                Anyone has any experience with humidity monitoring remotely?