Check out Eureka (the tent maker) and see if thet are still making free standing screen rooms. They used to have 2 different sizes, and you could purchase a "Storm Shield" separately. The storm shield completely covers two sides and fits on the frame. Because it's fitted, it does a good job. The frame is corded which makes for easy assembly and break down.
Mine is at least 20 years old, has been used continually, and it's still in great shape. So, needless to say, if I ever need another one, I'm going to see what they have to offer.