If you've moved to Utah from somewhere with milder winters, the snow load conversation is going to be the most surprising part of your deck project. The numbers are higher than people expect, and they get higher as you go up in elevation. For a deck or patio cover, the snow load is often the controlling design load — meaning it's the thing that determines how big your beams have to be.
The base number
Most of Davis and Weber counties use a base ground snow load of 43 psf for residential design. That's the starting point. Compare that to roughly 30 psf in much of the Salt Lake Valley proper, or 20 psf in St. George, or near zero in southern Nevada. We get real snow up here.
43 psf is the ground snow load — the snow accumulation on flat ground. The roof snow load (what your deck cover actually sees) is calculated from the ground snow with an exposure and slope adjustment. For a typical low-slope residential roof or patio cover, the roof load is about 70-80% of the ground load — call it 30-35 psf for the base case.
The elevation rule
Here's where it gets interesting. The Utah amendment to the IRC adds an elevation factor: above 4,500 feet, snow loads increase by about 6.3 psf for every 100 feet of elevation gain. So:
- A lot at 4,500 ft (most of valley Layton): ground snow ≈ 43 psf
- A lot at 5,000 ft (East Layton bench): ground snow ≈ 75 psf
- A lot at 5,500 ft (Eden / Huntsville): ground snow ≈ 105 psf
Bench lots in Kaysville, East Farmington, Bountiful, and parts of Ogden routinely sit at 4,800-5,300 feet. Foothill lots and anywhere in the Ogden Valley are higher still. The difference between a valley lot and a bench lot is real money on a deck cover or patio roof.
Why this matters for decks
Three different deck scenarios:
- Open uncovered deck. Lower effective load because snow blows off. Still has to be designed for snow, just at a reduced value.
- Covered deck or patio cover. Now you've built a roof. The full roof snow load applies. This is the scenario that catches most homeowners off guard — adding a cover to an existing deck almost always requires re-engineering of the deck structure below to take the increased load.
- Covered deck with hot tub. Now you've added live load (the tub itself, water, occupants) plus the snow load. We see deck failures from this combination.
What the engineering changes
Higher snow load means:
- Larger beams (bigger LVLs, or steel where wood gets impractical)
- Tighter joist spacing or larger joists
- Heavier post connections
- Larger footings under each post (the load has to get to the ground)
- Sometimes a different ledger fastening pattern
For a typical covered patio in central Layton, the structural scope is moderate. For the same patio in East Kaysville at 5,000 ft, the beams have to be bigger and the post-to-footing connections beefier. Same patio, very different engineering.
The practical takeaway
If you're building a covered deck, patio cover, pergola with a roof, or anything that's going to collect snow in northern Utah, get the engineering before you build. Don't trust a prescriptive code table that doesn't know your elevation, and don't trust a contractor who says "we don't need an engineer for this size." We've seen what happens to deck covers that weren't designed for the actual loads — usually after the first big February storm.
For the full deck and patio engineering scope, see our decks, additions, and remodels page. Send us your address and we'll plug in your actual elevation for a real quote.