Though a cozy back porch of any size offers a certain hammock-lounging allure in early summer and late fall, the much-loved connection between inside and out is rendered virtually useless during the cold and rainy time of year.

The biggest advantage to adding a sunroom, says contractor Tim Hubbard, is the addition of that open, outdoor feeling any time of year along with the chance to do away with winter "gloomies" when spring seems so very far away. In Europe or Britain, where constant rain seems to bring on the seasonal affective disorder known as "SAD," sunrooms are common places. A sunroom is a great way to be outside without feeling the rain or cold.

When well planned, a sunroom can be added to an existing home for about the same cost, or slightly more, as any other addition. At a basic level, sunrooms are framed rooms with windows in place of sheetrock.

Living in the Pacific Northwest, sunrooms, for the most part, should be positioned within 15 degrees of a home's southern-most point. If a home has an existing concrete patio or porch, a foundation is already in place for a full or partial sunroom. While sunrooms are available in kits, amateur do-it-yourselfers would be wise to seek professional help. Whether "from scratch" or kit, be sure to consider the final product of whatever you build, Bright Ideas sunroom contractor Chris Mathis says.

Often, having a contractor install a kit, or build a sunroom from scratch, costs only slightly more than a do-it-yourself setup and a professional job will afford better results and offer custom options such as built-in shades, special-order colored glass and fun angles.

"It's important to remember that your property value goes up depending on the quality of what you build," Mathis says.

Basic construction of a sunroom involves framework, made of (in order of value and cost) PVC, aluminum or pressure-treated wood. Like any addition, sunrooms must be built according to local building codes and on level foundation. In areas that experience freezing during winter, foundations must be constructed at a level deeper than the frost line (about three to four feet below ground here) to prevent shifting when the ground expands and contracts during winter.

While a wood frame floor will suffice for a sunroom, concrete is easier and brings the added effect of absorbing heat from the sun to re-release when needed. Tile is also nice to add later.

As far as room design, sunrooms can be constructed in virtually any shape from octagon to triangular or even a dome. Roofing can be done in a variety of angles or it can be all glass or regular roof material with standard skylights.

Standard windows are included in sunroom installation and consumers should opt for safety-tempered glazed glass with high insulation value. A high glaze surface will generously collect sunlight when needed and block out those toasty rays on warmer days.

As for color, custom order sunroom glass runs the gamut from azure blue and bronze to greenish brown and deep tinted black. Decorative trim affords a "dressed up" look with special trim strips and moulding to match the rest of the home.

"When you have one built from scratch, it's all up to the homeowner's imagination at that point," says Mathis. Another consideration, a new product available on the market for larger buildings, self-cleaning glass is textured in a way that the occasional rain, or spraying off, will keep glass nice and clear without hours of elbow grease.

In between framework and windows, insulation will keep temperatures stable.

Typically, framework for sunrooms is done of 2 by 6 beams instead of 2 by 4 to allow more space for insulation.

Cost wise, Hubbard and Mathis estimate sunroom construction to cost anywhere from $100 to $250 per square foot depending on the degree of customization required and quality of materials.

Aside from added indoor living space, a sunroom can drastically add enjoyment of an otherwise dreary area of the home and, ultimately, add substantial value.

"There are a lot of 1,400-square-foot homes in the valley that will add a 400-square-foot sunroom and you can completely change the entire mood of the home," Mathis says. "A sunroom really changes a living space for the better."