I read it as meaning at least 1,000 years. Modern humans started living in caves in Europe about 100,000 years ago, and their cave-houses still exist. So, if yo

I read it as meaning at least 1,000 years. Modern humans started living in caves in Europe about 100,000 years ago, and their cave-houses still exist. So, if your house is also a cave you should be able to get at least that. If they want the house to last for exactly 1,000 years then I'm not sure what to tell you. Maybe something based on the milleneum clock? Or explosives and a really long fuse, Wile E Coyote style?