We're lucky in that we have a downstairs and an upstairs loo. When we had workmen in recently, I showed them where the downstairs one was, and told them not to knock, but to come in and use it. I provided plenty of liquid soap and some old towels. At the end of each day I bleached everything down, removed the used towels and put out some fresh ones for the following day. It didn't take long, and I appreciated how my husband would suffer if he didn't have access to a toilet for a whole day.