Moisture sensor for wood (timber)

I have a leak in the bathroom causing some joists to be damp. I’d like to monitor the dampness of the wood to ensure that repairs are successful and warn of future leaks.

The Grove Moisture sensor seems to be designed for soil, would it also work if attached (taped?) to a wood surface?

Alternatively the water sensor seems to be designed to detect standing or running water as opposed to dampness.

Should either of these work for me or is there something else? This would be for the GrovePi+.