I dont understand! I would of thought roofing would be the cause of higher premiums (more to go wrong!). How much are you paying for the window cleaning and who is it with? And to answer your question, With some companies if a certain percentage of your work is wfp then they will offer a discount on their premium. The one I am with don't but it is still less than it is through one that does! I've got £5 million public liability insurance and it costs me £106.84. Thats not a lot £2.05 a week. Thats not a lot! You have to shop around just like motor insurance.