Adjective
1. run-down
2. tumbledown
3. ramshackle
4. broken-down
5. in disrepair
6. shabby
7. battered
8. beat-up
9. rickety
10. shaky
11. unsound
13. in ruins
17. decrepit
18. neglected
19. uncared-for
20. untended
21. the worse for wear
22. falling to pieces
23. falling apart
24. gone to rack and ruin
25. gone to seed
Verb
26. decay
27. crumble