I'd suspect the screens are being used to 'hide' the problem. First, contact the builder via certified letter, return receipt. Document any phone calls or one-on-one conversations. (Date and Time them too.) I would suggest that you retain an attorney. It's not unusual to have one for a new home (during the building process and at closing) as it is when you're buying an existing home. I had an attorney throughout the entire home buy process, and we bought an existing home. Low and behold, when the sellers left a lot of 'old' paint in the basement that we specifically asked to be removed when they moved, the attorney was already retained AND he took care of getting 'someone' to dispose of the paint.
When you're about to spend 100's of thousands of dollars on a new home over 15 - 30 years, you ought to spend a few hundred $$$ for an ASHI-approved, New Home Inspector and a Real Estate Attorney. BOTH shouldn't cost you more than $1000. That's good peace of mind when it comes to the $$$ you'll spend for your home. (Figure it out. $1200 per month (excluding taxes) for a mortgage, x's 12 months, x's 30 years. Is $1000 THAT much money?!) The Home Inspector for a new home typically comes out 1) when the foundation is poured, 2) when the frame is up, 3) when the plumbing and electrical is complete, 4) when the house is walled and roofed, and 5) when the home is complete. Make sure you get your Home Report from an inspector who does it On-Site! You dont' want to wait a week or so to hear that the electrical is poorly installed, whereas the walls are now up!
As for calling the county inspectors, that's an option, but the lawyer will usually write a letter to the builder to give him an opportunity or 2 to correct the problem. After that, it's a matter for him/her and the builder. My best to ya and hope this helps.