Audio problem: When Becky runs down the stairs and yells "Mom!" you can hear the echo throughout the sound stage.
Canoga Time - S1-E11
Audio problem: When Dan and Roseanne start throwing things in the yard, you can hear it's not hitting grass or a porch, it's hitting a floor (from the set it was filmed on).
Answer: Clearly, the only person who could truly answer this question would be a set designer for the series, or someone else directly connected to the series who would have this kind of detailed information. I looked on IMDb.com and Cheryl Lanner is credited as set designer through 1997. I quickly found her Facebook page, and I directed your question to her. After some time, Ms. Lanner has replied as follows: "I decorated the last season 1/2 but after 9 seasons the sofa just plain got worn out and had to be repaired from 8 years of usage. There was a board put on the sofa but as I've said, it was due to so much usage. If they had back problems I was unaware of them, but you can be assured that if that was the problem it would have been fixed immediately. Take care Michael!"
Michael Albert