moisture proofing enclosure?

[Brently]

Okay so I have had a large wooden enclosure that I have made for a couple years now. I have recently noticed that I have discoloration on the wood where the humidifier comes in and around the water dishes. I did seal the wood but apparently not well enough. I am thinking of putting in linoleum or something of the sort. Any other ideas or suggestions or comments would be helpful. Whatever I do needs to be something that doesn't require a long period of time to set as I don't have an alternate enclosure to place Athena in. Any help is appreciated.