Random factoid: The oldest working door in Britain is in Westminster Abbey. This door was put into service in the 1050s. In a few more decades it turns 1000 years old.
Yeah that's me hedging my bets. There's probably some 7th or 5th C door somewhere being used as a tabletop or wall panel. And boy would that be embarrassing!
(Actually I know of one. At Vindolanda one of the early wooden forts had a wooden floor that used a recycled door in it! So there's one that's like 1930 years old!)
