I think this is a great Idea first this type of company is refferal company. contractors are scammers you have to carefully screan all your contractors to make sure that they are honest
starting by offering a service like cleaning or decorating and renovating. the cleaning and decorating part you can do it or hire somebody else to do it, but the renovating part such as bathroom painting door repairs carpet elctricity you contrat that out. by making the contractor work for you as an independant contrator.that way they won't scam the client nor put your business at risk this type of business is all about integrity and trust and also good service. all you'll have is good words of mouth
ways you can do it is charge the contractors a % or a flat fee for each clients you give them.
let me know if that help a little bit and if you need more help how to start. I can help you and guide you to the right direction
good luck.