Composite Deck Building in Salt Lake City, UT

Composite deck building makes sense in Salt Lake City for one main reason: the sun. At about 4,300 feet, with dry air and roughly 3,000 hours of sunshine a year, wood boards fade, check and split quickly unless they are stained on schedule. Capped composite and PVC boards have a protective shell that resists fading and staining, and they do not need sanding or sealing. The trade-off is a higher upfront cost and, with some colors, a surface that gets hot in July.

What composite is, and what it is not

Composite decking is made from wood fibers and plastic, usually wrapped in a polymer cap. PVC decking is all plastic, lighter, and generally resists moisture best. Both are boards only: they sit on a wood or steel frame, and the frame still has to be built right. Most composite decks in the valley sit on pressure-treated lumber framing, which is why we pay as much attention to joists, beams, posts and footings as we do to the boards you see.

The frame under the boards

Composite boards usually need tighter joist spacing than wood, often 16 inches on center or less, and closer still for diagonal patterns, as manufacturers' installation guides specify. Salt Lake City's design criteria call for footings below a 30-inch frost depth and a minimum ground snow load of 28 pounds per square foot, with higher snow loads above 4,239 feet. We size the frame for both, and we use joist tape or flashing on top of the framing to slow water damage where the boards cannot be seen or reached later.

Heat, color and grip

Dark composite boards can get uncomfortably hot under full sun in a Salt Lake summer. Lighter gray and tan tones stay cooler, and some product lines are marketed as heat-mitigating. If the deck faces south or west with no shade, we bring samples so you can see and feel them, and we talk about adding a pergola or cover. Most capped boards have an embossed grain that improves traction, which matters when snow melts and refreezes on the surface.

Gaps and expansion

Composite boards expand and contract with temperature, and Salt Lake City swings from single-digit winter mornings to summer afternoons near 100 degrees. Manufacturers specify end and side gaps by temperature at installation, and hidden fasteners are designed to hold those gaps. We follow the installation guide for the product you choose, because that is also what the manufacturer's warranty is written around.

About manufacturer warranties

Composite brands typically back their residential decking with limited warranties. Trex, for example, says its residential decking and railing warranties range from 25 to 50 years, depending on the product. Terms differ by line and usually require installation to the manufacturer's instructions, so we give you the product information and keep the installation in line with the guide.

Snow removal on composite

Composite can usually be shoveled with a plastic shovel pushed along the length of the boards, since metal blades can scratch the cap. Brands differ on which ice melts they allow, so we give you the care sheet for the boards you choose.