How do I stop the furniture labourers to not use my new house's bathrooms?

Basically bought a new place and starting interiors. The daily wagers are people who don't give a flying fuck anything and just misuse your premises. They damage the bath fittings, spit everywhere, dirty the room. The red pan masala stains don't go away and I have bought the house with money earned out of my heart and soul and want to build a dream house. While I am trying to figure if I can lock the bathrooms and warn them to use the public washrooms in refugee area, what can I do to stop them entirely? Please don't tell me "certain things you cannot control", "these things cannot be addressed", etc. because those are my final options and I am here to seek help from the community.