Open concept main level with direct sight line from front to back of house. (robgolfi.com)
The rule: if you can not be in direct sight of your dog, he must be contained in a crate or other small area. (homevet.com)
As long as he does not react to the door closing in a negative manner, you can leave it closed a few moments longer each time, staying in direct sight. (centralparkpaws.net)