Rust Decay for rocks and water bases

I know it has the BuildBlocker and TwigDecay plugins, but a good idea would be a "mix" two, where the foundations built on a rock or water, had decay / minute.

Examples:

• Twigs: -1 HP decay each 60 minutes.
• Wood: -10 HP decay each 60 minutes.
• Stone: -30 HP decay each 60 minutes.
• Metal: -20 HP decay each 60 minutes.
• Top Tier: -80 HP decay each 60 minutes.

All configurable (levels, time span and value).
Who build on rocks and water, will have to take the risk that may lose the base.

Sorry my bad english.
Thanks!