Deck Safety in Greater Denver

Most deck collapses are not freak accidents. The cause is almost always a slow-motion failure: a ledger that started letting water past the flashing years ago, lag screws that lost grip every winter, joist hangers driven with finish nails by a previous owner saving twenty bucks at the lumber yard.

Why Deck Safety Matters

NADRA reports that 30 million of the 60+ million U.S. decks are past their useful service life. IRC requires 40 psf live load plus 10 psf dead load: 20,000 pounds on a 400-square-foot deck, hanging off a few small connection points. When any one corrodes, rots, or was never installed correctly, the deck does not feel different to walk on. Right up until it does.

Common Risks of an Unsafe Deck:

  • Rotted ledger boards, joists, or beams
  • Rusted or backed-out fasteners
  • Loose guardrail posts that flex under a hard lean
  • Wobbly stairs with uneven risers
  • Footings heaved by Colorado freeze-thaw cycles
  • Missing flashing behind the ledger is the single most common cause of catastrophic deck collapse
Download NADRA's 10-Point Check Your Deck® Checklist
A covered deck with a pitched roof is attached to the back of a gray house, featuring a black railing with horizontal cables. Metal stairs descend to the grassy backyard. The area beneath the deck is a covered patio, and to the right, a semicircular brick patio holds outdoor furniture and a grill.

How to Know If Your Deck Needs an Inspection

Warning signs:

  • Soft or splintering wood around the ledger, posts, or railings (a screwdriver tip sinking more than a quarter inch means rot).
  • Rust streaks running down the siding below any lag screw or bolt.
  • Movement at the top of guardrails under a hard push; IRC R301.5 requires resistance to a 200-pound load.
  • Standing water on the boards 24 hours after rain.
  • Stair treads that flex underfoot or risers varying by more than 3/8 inch.
  • Cracked footings or pavers at deck post bases, an early sign of frost heave.
Schedule a Deck Safety Review

“Most decks I look at don’t need a rebuild. The fix is usually three or four small things, caught early.”
Brian LaFave, Western Sky Designs

The Four Key Elements of Deck Safety

1. Structure

Footings below frost line (30 to 36 inches in Greater Denver), Simpson ABU post bases, beams, and joists sized per IRC R507.5/R507.6 for the local snow load.

2. Connections

Ledger lag-bolted per R507.9.1, joist hangers nailed in every hole, two DTT2Z lateral hold-downs per R507.9.2 within 24 inches of each end, galvanized hardware rated for ACQ-treated lumber.

3. Surface and Drainage

Boards spaced for water shed, hidden fasteners to torque spec, no standing water on the walking surface.

4. Environmental Factors

Tree limbs trimmed back, snow shoveled after heavy storms (a 6-inch accumulation adds 20 psf), and lighting on stair treads at night.

Simpson Strong-Tie Deck Center
2025 Deck Connection & Fastening Guide
An elevated outdoor deck with a partial covering and dark wood planks, featuring a black metal railing, overlooking a grassy backyard. Below deck is a concrete patio, and to the right is a brick-paver patio surrounding a tree.

What Greater Denver Conditions Do to a Deck

  • Freeze-thaw cycles. Greater Denver averages over 100 a year, four times what most coastal climates see.

  • Snow load by elevation. Denver sits at 30 psf; foothills jurisdictions can require 50 to 80 psf.

  • High-altitude UV. At 5,280 feet, UV intensity runs roughly 25% higher than at sea level; softer board systems fade and embrittle faster.

  • Hail and Chinook winds. 1- to 2-inch hailstones land on horizontal surfaces every few years. Foothills designs must handle 95-110 mph wind events.

How Western Sky Designs Approaches Deck Safety

Existing-deck inspections

A 30-minute structural walk-through, verbal report, and written estimate.

Code-compliant new builds

Plans drawn against the local snow load, frost depth, and wind requirements. Permits pulled, final inspection included.

Code-compliant new builds

Plans drawn against the local snow load, frost depth, and wind requirements. Permits pulled, final inspection included.

3D rendering on every proposal

Plus a 2-year workmanship warranty on top of the manufacturer’s warranties.

Get an Inspection or Estimate

At Western Sky Designs, deck safety is part of the design from the first sketch, not an afterthought. Since 2001, the company has completed over 300 custom decks and outdoor living installations across Greater Denver, applying current IRC code, manufacturer specifications, and proven structural detailing on every build.

For more deck safety information:

North American Deck and Railing Association (NADRA)
Simpson Strong-Tie Deck Center
Contract Questions

Stop! About to Sign That Deck Contract?

Make sure you’re not missing anything before you commit to building your outdoor space.

Contracts should protect you, the homeowner. But many leave huge gaps around permitting, warranties, and unexpected delays.



Download our Critical Questions Guide for free. It’s the ultimate protection plan to ensure your new outdoor living space is Built Better.

Written by Western Sky Designs, your trusted custom builders in the Greater Denver Area.

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