Sisters Kirsty and Fiona Innes, who have 13 years' teaching experience between them, have set up Aardvark Cleaning - and the move has been such a success that they say they will never need to teach again.
The pair, from Bath, are attracting two new clients a day and soon hope to be earning more than their combined teaching salary of pound;47,000.
Kirsty had taught for seven years, but eventually found pupils' unruly behaviour and the demands of the national curriculum too stressful.
"There was a general lack of respect for teaching staff. We were both at really nice schools. We had no problems with the management - it was all from the kids. Teachers just have no control because we do not have any powers in the classroom," said Kirsty, who did not want the school involved to be named.
"We were trying to deliver a national curriculum that does not suit a huge proportion of the kids.
"Everything needs to be assessed all the time, but you just can't assess some qualities through examinations. I felt like I was hitting my head against a brick wall."
After Kirsty had her second child - a girl - two years ago, she found that the stress of life at school was affecting her at home.
But it was only at a family barbecue last summer that Kirsty, 34, and her 27-year-old sister, Fiona, realised that they were suffering the same problems at work, and decided to set up their business, Aardvark Cleaning.
Working with Fiona's husband, a website designer, they launched their business on the internet. And their brother Jamie, 31, is also expected to join the enterprise.
Andy Woolley, south-west regional secretary of the National Union of Teachers, said the sisters' decision to quit teaching was not unusual.
"The workload continues to drive many teachers away," he said. "There have been some improvements, but it is still excessive and the amount of time teachers spend working at home preparing and marking is too great.
"People come in dedicated to the idea of teaching and then find out about the workload and how hard it is.
"They also see their friends in other careers and having more money, as well as the time to spend it."