Although technically not considered rooms, most outdoor spaces added to homes are room-size or larger and have the same basic elements-and some of the same features and amenities-as regular room additions. All require a proper foundation and solid floor construction, and many involve some type of cover plus a sturdy structure to support it. In short, an outdoor living room has everything that indoor rooms have except solid exterior walls. Therefore, they require a similar amount of planning, labor and expense to do a good job of boosting your home's livability and value.
The simplest open-air "room" is a single-level deck or terrace with no cover. However, it's also the most limited in terms of livability because it provides the least protection from the elements. Adding a cover, such as a trellis or awning, boosts livability considerably but also introduces extra structural and aesthetic considerations. A full-fledged open porch, complete with posts, railings and a pitched roof, offers a sense of enclosure and protection similar to an indoor room. Adding screen panels heightens this sense of enclosure-and allows you to enjoy the space without having to arm yourself with flyswatters and bug spray.