Behind the house-to-ceiling height and area are not included as a floor, defeasanseKE created by removing part of the floor and ceiling on the top floor of the floor is not feasible as long as the effect on the strength of the structure. To create a skylight in the roof of the existing, relatively easy to be very large windows. Can be used as a catch-all without regard to volume ratio. However, it is important to do well and for reinforcing the strength of the roofGENAI waterproof and to prevent leaks.