I have flies after painters came
I'm a cabinetmaker. One year I sprayed outside some awesome cabinets I'd made for a customer. I had fruit trees on my property. Within seconds I had thousands of fruit flies descending on the wet paint. The reason? The paint, particularly when sprayed and "atomized" is sweet smelling and the fruit flies go for it.  I've had it happen again at another location. Different paint, but also sweet smelling. 

The solution: You'll have to screen off the area. Any open doors or windows and they'll find a way in.....