Residential screened porches are an in-between place. They reside at the transition between the protection of the indoors and full exposure of the outdoors. Neither fully interior nor exterior, screened porches can subtly blur the line between indoors and out.
As structures, screened porches can be challenging to design and build because they are subject to the elements and weathering forces of nature, yet they often are expected to have a fine and enduring finish and desirable amenities much like an interior space. Porches should provide shelter from the heat of the summer sun, biting insects and chilling winter winds, but they also must welcome the warmth of the winter sun and cooling breezes in summer. With careful consideration of location, orientation, appropriate architectural form and details of construction, screened porches can provide just the right amount of shelter to allow one to relax and enjoy the sensory aspects of the outdoors.
The art of locating a screened porch is a function of the intended goals for the porch combined with the realities of the place at hand. Although it may seem simple enough to build a screened room next to an interior space, many factors can influence the form and expression of the final design.
The existing layout of spaces in a house is always the starting point for locating a porch. This layout is a given, as is the home’s relationship to all of its surrounding environment, including the existing topography, compass orientation, adjacent structures, existing vegetation and proximity to roadways.
Goals for a new porch will necessarily interact with the factors inherent in the porch’s surroundings. Ideally, the floor plan of a home will lend itself naturally to the addition of an attached screened porch. Likewise, the environment will cooperate: Cooling breezes will arrive at just the right side of a proposed porch, and the movement of the sun relative to the proposed location will be such that its rays can be welcomed or avoided as desired. In practice, however, all the factors that weigh into locating an attached porch addition will likely not be ideal. Therefore, relevant factors must be assessed in relationship to the goals for the structure. As in everything, choices must be made to maximize desired outcomes and minimize undesirable ones.
As an example, a recent Austin, Texas, porch project had goals that were somewhat at odds with its location relative to its environment. The porch was intended to provide a relaxing spot from which to enjoy the backyard gardens of the property. Its proposed location on the north side of the existing house—just outside the kitchen—put it at a less than ideal location to take advantage of the prevailing southerly, cooling breezes in summer. Careful siting, however, allowed the southwest corner of the L-shaped addition to open to and catch these breezes; thus the porch could provide a relatively cool and pleasant environment.
It should be noted that goals with regard to the environment will vary with geographical location and may also vary during the course of the seasons. In Texas’ climate, for instance, relatively mild winters allow for year-round use of a screened porch. During Texas winters, the sun is welcomed; otherwise, shade is prized. Southerly breezes are welcome year-round (in the winter, they are warming), but northwesterly arctic winds in winter call for protection.
The sun travels in predictable paths throughout the day and, in turn, the seasons. Given this predictability, a design can be achieved to bring in or protect from the sun, depending on the desired outcome. Sunlight early or late in the day is low, whatever the season, while the angles of the sun at midday vary dramatically during the course of the year. In latitudes away from the equator, winter sun comes in low at noon, whereas summer sun is nearly directly overhead. With attention to roof overhangs, the midday sun can be blocked or allowed in as desired. Morning and afternoon sun can be blocked, as well, with solid or movable means. The dependability of the sun’s movement is relatively easy to accommodate with considerate design.