Yet house sunrooms occupy a hazy middle ground in the building world. Some sunrooms are site-built with lumber, trusses, joists, foundation, electricity, and sometimes even plumbing. Since they are habitable, they qualify as accessory dwelling units or ADUs. These are always contractor-driven permitted projects subject to building codes. Except for the large number of windows and skylights, these sunrooms might more properly be called room additions or bumpouts. On the other end of the scale are pre-fabricated sunroom kits. These sunrooms go up quickly, require less permitting, are less expensive, and can often be built on a do-it-yourself basis. In some cases, they do not require foundations and can be built right onto an existing concrete patio slab or a sturdy ground-level deck. A sunroom tends to be heavily fenestrated—that is, windows and skylights. Besides windows, it often has sunroofs or the entire room might be made of glass. While plants do thrive in this environment, with this type of sunroom the focus is more on living than on gardening. Combining the idea of a bumpout with a sunroom gives you a bumpout hybrid that is heavily focused on sunlight and relaxation. This hybrid usually does not contain sleeping quarters, a kitchen, or a bathroom. The walls are always substantial 16- or 24-inch on-center wood-framed, insulated walls. The sunroom aspect is that these walls are populated with far more windows than might be found in an ordinary sitting room. From the exterior, these custom-built hybrid sunroom-bumpouts blend in well with the rest of the house. Siding, paint, roofing, and window styles all match. The only clues that this might be a sunroom are that it has an unusually large number of windows and that it extends farther into the property than the rest of the home. This type of sunroom has been previously designed and built elsewhere, off-site from the home. Its design is independent of any individual house. Usually, companies that design and build pre-fabricated sunrooms create a number of styles, shapes, and sizes so that homeowners can find one that best matches their own home. Unlike stick-built structures, which are constructed of wood and drywall, pre-fabricated sunrooms are chiefly made of steel, aluminum, tempered glass, and foam insulation. From the inside, pre-fabricated sunrooms retain not just an exterior wall but the look of that wall. The home’s exterior siding usually stays in place and doors that lead into the house are retained. From the outside, these sunrooms look very much like add-ons. These sunrooms usually have metal roofing. Since glass covers nearly every vertical area, it is not possible to continue the home’s siding onto the sunroom. Three-season sunrooms are lightly built and work well when the sun is strong. But during the winter, when temperatures dip low and the sunlight is at a premium, these three-season sunrooms are usually too cold to be habitable. Four-season sunrooms have extra insulation and care has been taken to run heating or cooling out to that space. Conservatories exist in real life, too. A conservatory is the type of sunroom lots of people think of when they think of sunrooms: vast fenestrated structures flowing with plants and sunlight. If you have a green thumb, then plants and flowers are the focus of a sunroom conservatory. This type of sunroom nearly approaches greenhouse status since all walls and even the roof are made of glass. The conservatory’s floor, too, is usually hardscaped in porcelain or ceramic tile, natural stone, or concrete for easy cleanup after watering. When there is furniture, it is usually outdoor furniture made of resin, coated wood, or metal since the humidity levels would ruin fabric-covered furniture. Usually, though, furniture is kept to a minimum. Conservatory-style sunrooms are best for dedicated gardeners. Resale value for these types of sunrooms can be on the lower end since they are not habitable and because not all potential buyers are guaranteed to be such avid gardeners. Sometimes, this sunroom still retains most of the back porch’s building elements. The flooring, roof, ceiling, and walls are the same. The only difference is that the open or screened windows have been replaced with glass windows. Since porches tend to receive the worst damage that the elements deliver, they aren’t always build-ready. Unless the porch is relatively new and in good shape, it may not be able to be converted into a sunroom.
