It appears that they do not like to be locked in the room. Something you may want to consider would be to properly use a crate for when you leave along with exercise before you leave.
As far as the doors and base go it is not looking like an easy fix.
Screw a piece of plexiglass to the door. They will not like it because their toenails will slip off. Then of course you will probably face another issue after that. You could also call the Dog Whisperer.
Hmmm.... our dogs did this when I was a child but my parents just left the doors as is. Fix them or replace them and the dogs would only go and ruin them again.
Things like this are just what you tend to have to put up with when you have dogs imo. Unless you're really great at training them, which I guess we weren't (they were a very 'hyper' breed naturally however, not that I'm making excuses...!)
Edit to add:
Just thought, if you were to replace your doors I'd really recommend these http://www.ukoakdoors.co.uk/ I used them recently and they were lovely to deal with and the doors are great.
Again though, you might just want to accept a less than perfect looking home while your dogs are around (they're definitely worth it!)
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