Utah is hard on decks. The winters bring snow load, the freeze-thaw cycles work water into every fastener and joint, and the dry summers bake the wood until it cracks. A deck built in Florida or Arizona doesn't translate. Here are the five things that determine whether your deck holds up to two decades of Wasatch Front winters.
1. Sized for real snow load
Most prescriptive deck spans assume modest snow loads. Davis and Weber County aren't modest. Beam and joist sizing for any covered deck or patio cover needs to account for the actual ground snow load at your specific elevation — 38-45 psf in most of the valley, more on the bench. See our snow load post for the elevation rule.
Practical effect: covered decks and patio covers in northern Utah usually need bigger beams and tighter joist spacing than what national prescriptive tables suggest. Engineering catches this. Eyeballing it from a span-tables app doesn't.
2. The ledger connection done right
The ledger — the board that attaches the deck to the house — is the single most-failed deck component nationally, by a wide margin. Here's what matters:
- Lag bolts or structural screws, not nails. Sized and spaced for the actual load.
- Bolt the ledger into solid framing (rim joists or a band board), not just into sheathing or trim.
- Use the right edge distance. Bolts too close to the edge of the ledger or the band split out under load.
- Tension ties. Modern code requires hold-down tension ties at the ends of the ledger to prevent the deck from pulling away from the house under lateral load.
- Flashing — and this is the big one for Utah. A metal Z-flashing over the top of the ledger, integrated into the house's siding and weather barrier, that prevents water from getting trapped between the ledger and the house.
Most ledger failures we see happen because water sat between the ledger and the house siding for years and rotted the band joist behind it. By the time anyone noticed, the bolts were pulling out of mush.
3. Footings deep enough for frost
Davis and Weber County frost depth is typically 30 inches. Your footings have to extend below frost — otherwise the soil freezes, expands, and lifts the footings (and your deck) seasonally. Over years that movement loosens connections, cracks decking, and tears decks away from houses.
Engineering note: 30 inches is the minimum. Some lots with higher water content or unusual exposure may need deeper. We design to the actual conditions of your lot.
4. Fasteners that don't corrode
Modern pressure-treated lumber is more corrosive to fasteners than the older CCA-treated lumber it replaced. That means you need:
- Hot-dipped galvanized fasteners (G185 minimum) or stainless steel
- Connectors rated for the new pressure-treatment chemistries
- Stainless or polymer-coated screws for the decking surface
Standard zinc-plated fasteners in modern PT lumber can corrode through in 5-10 years. Don't use them.
5. Drainage and water management
Standing water is the long-term enemy. A few details:
- Slope the deck slightly (1/8" per foot) away from the house
- Leave gaps between deck boards to let water through
- Use joist tape on the top of joists to keep water from sitting on the wood under the decking
- For covered decks, design the cover to shed snow without dumping it on the house wall
- Make sure water from the roof above isn't dumping onto the deck through downspouts
The summary
A deck that's engineered for real snow loads, built with a properly flashed ledger, on footings deep enough for frost, with the right fasteners and good drainage, will last as long as your house. A deck that's missing any one of those is on a shorter clock. The structural engineering covers items 1, 2, and 3. We can help with all three.
See our decks, additions, and remodels page for the full scope.