Deck repairs

We are a 56 unit self managed Condomium in Wisconsin. We would like to implement a rule regarding repairs. Owners are responsible for their decks and most owners are very good about staining and upkeep. Some have replaced with composite decks. We have a few owners who just ignore the notices we send to repair. Does anyone have any rules or regulations regarding owner responsibility repairs and how long we should give owners to complete. We typically ask them to advise us when the repairs will be made within 30 days of sending the notice. Then we typically give them up to 6 months to make the repairs. We have a couple of owners who just ignore the notices. No reponse and no work done in almost 2 years. Notices do state if work is not completed, Association will have work done and owner assessed for costs, but no one wants to take that step. Possibility of being accused of trespassing etc. If we have something in our rules and regulations owners may start paying attention.