Strict new fire codes had California architect Doug Ewing searching for alternatives to wood decking. For this project, he used metal grates.
Magnus Stark Strict new fire codes had California architect Doug Ewing searching for alternatives to wood decking. For this project, he used metal grates.

With California building fire codes becoming increasingly strict, architects such as Doug Ewing of D.S. Ewing Architects, in Pasadena, Calif., have to find creative options for exterior designs.

The project pictured at right is located in an area where fire code requires that decks that project off the exterior wall be made of a fire-rated material. Ewing chose aluminum grating for the deck, supported by 4x10 Douglas fir joists that project from the house. These wood joists were acceptable at the time because when Ewing designed this project, 4x10 joists qualified as heavy timber and were allowed by code. Since then, however, the code has been updated and now requires heavier 6x10 joists. When installed every few feet for a deck base, Ewing says, the aesthetic is not ideal.

The metal grates on this project also allow sunlight to pass through, so the vegetation can continue to grow below. Ewing included shallow grates that cantilever out on both sides of the 15-by-20-foot deck to act as a screen to shade the lower windows, as well as to provide a catwalk to clean the upper windows. He also specified a metal handrail and metal horizontal cable railings.

Some areas in California have banned any wood on home exteriors. “This is not good if you want the rustic, warm look of wood,” Ewing says. He says that homeowners purchase existing properties with wood on the exterior, not realizing that any renovated segments will not be allowed to include wood.

Ewing has used HardiPlank fiber-cement siding in 4x8-foot sheets to create a more modern look. “We’re trying to be clever with new products to create contemporary building with no wood on the outside,” he says.

Deck Specs: Metal Alternatives

Ewing selected McNichols aluminum grates ($30 per square foot) with ½-inch openings because they’re comfortable to walk on. The grates are rated to hold 100 pounds per square foot, so he spaced supports 3 feet apart. Though the deck contractor was not familiar with the product, he had experience working with metal for commercial kitchen projects. He cut the 20-foot-long by 3-foot-wide pieces on site and used screws to attach them to the joists. “It’s not that hard — a skilled woodworker could do this using the right tools,” Ewing says.

Though wood and plastic composite decking is another alternative to wood in restrictive fire code areas, Ewing doesn’t like the faux wood texture or the color options available. Also, unlike the aluminum grates, the composite can’t span four to five feet, requiring rafter support every 16 inches, and Ewing says that he prefers longer spans between rafters because it’s more aesthetically pleasing.

Nina Patel, senior editor, REMODELING.