Our house is around 130 yrs old . We were planning on taking down a wall on the second floor that has an original, non functioning chimney through it. Nothing vents through this chimney; nothing has vented through it for decades and it was sealed over for decades. The chimney continues down to the basement which is a dirt floor. We had professionals come and take down the chimney to just below the roof and patch up the roof. We were going to do the work ourselves and take down the rest to the 2nd floor.
Plans have changed and we will not be taking down the wall. So we now have an open chimney inside the roof. Should we cover the opening or just leave it open? The only thing we could think of is that mice or small creatures may climb up from the dirt floor basement. Any other problems that we aren't taking into account?