You can't deduct for it. It may not be to your liking, but it's what you're agreeing to buy.

You can deduct it in your head as you set the amount you're comfortable with, as you'd do for anything. But that doesn't mean it's a legitimate figure that you can "expect to deduct" as far as the seller is concerned; some people may be tickled to have a conversation pit, and that's who he'll sell to.

The cost of replacing a failing roof or HVAC unit or a structural issue is legitimate, but the conversation pit is a choice (like the color of the carpet--which you also can't expect deduct for).