Though construction costs vary depending on size, features and materials, architects and builders say a good estimate is roughly $70 per square foot. So, a basic 8-by-10-foot porch (80 square feet, roofed and screened) would start at about $5,600, with the design costing about $2,000 to $3,000 more, plus a few hundred dollars for permits and city or county inspections.
Vaulted ceilings, lighting, outdoor-graded electrical systems, fans, fireplaces, tiling, molding and structural considerations all add to the cost, so a deluxe, larger porch with all the bells and whistles can cost 10 times that amount.
Meg Clarke, principal with D.C.-based Clarke Architecture, who has designed several screened porches in the Chevy Chase area, says the square footage on nice decks, “not pressure-treated boxes,” is in the $200 to $300 per square foot range, “especially if it is small. If they were a bit bigger, the cost would be more like $150 to $250 [per square foot].”
One Clarke-designed porch in Chevy Chase cost between $50,000 and $55,000, including labor, materials, special features, design and permits. Simpler porches can cost half as much or less.
Flooring choices are many, and materials vary greatly in cost and performance.
Patrick Briggs, owner of Briggs Home Improvement, used Cambara wood, a reddish, medium-grained tropical variety, on a porch he built for his wife, “who loves hats, mint juleps, and wrap-around porches.” But he said he wouldn’t use the wood again, finding that it doesn’t hold up well in direct sunlight and exposure to the elements. Instead he recommends the Brazilian hardwood, Ipe. The prized Ipe is difficult for carpenters to work with, however, and can double the cost of a porch.
Contractors often find that people are upgrading their decks to a screened porch and doing away with the old — pressure-treated wood or cedar, which rots — to one of the man-made combinations of wood and plastic. There are more than 20 varieties of man-made materials, each of which has its pluses and minuses. “Some stain, some don’t, some scratch, some don’t,” said Michael Thiede, who owns Bethesda Contracting in Chevy Chase.
Now products such as Azek, a type of PVC plastic, and plastic-wood composites such as Trex are widely available. Builders said they tend to be durable and resistant to mildew, rot, scratches and stains. The composite and PVC decking materials add $7,500 or more to a small rectangular porch, compared with traditional wood.
If people are spending $20,000 or more for a porch, they typically add amenities such as ceiling fans, skylights, recessed lighting, fireplaces and even kitchens. They also make such porches semi-weatherproofed so there’s reasonable protection from driving rains.
Porches usually take two or three weeks to build, Thiede said. “It is not complicated.”
There are other practical considerations:
l Indoor light: A screened porch will block some natural light from entering the house, so some owners install skylights in the porch or carefully choose where to place the new porch.
l Water drainage: Some architects follow the old wisdom of designing a porch with a slight slant away from the house so that water will drain more easily. Historic preservation specialist Amanda Molson also recommends installing a porch railing with a beveled edge, allowing water to drain quickly, rather than lingering on a horizontal surface.
l Screens: Dogs, squirrels and other creatures can paw or gnaw though traditional aluminum mesh. Stronger fiberglass screening is available in rolls and costs less than the traditional aluminum, said home-improvement contractor Patrick Briggs.