Decking · Cold, hard freeze–thaw
How a composite deck ages in Salt Lake City, UT
In Salt Lake City, sun is the main stress on a composite deck: UV ranks #15 of 25 cities we cover and there are about 62 days above 90 °F. Capped boards lighten noticeably in the first two years, then stabilize; dark colors also get hot underfoot. Model estimate: 23–30 years of service.
Storyboard
20 years in Salt Lake City, washed yearly
Salt Lake City’s wear fingerprint
Each bar is scaled to the highest of the 25 cities we cover; the black line marks the median.
NOAA station SALT LAKE CITY INTL AP (USW00024127, 6.4 km away), 1991–2020 normals · humidity & UV: NASA POWER.
What fails first here
- 1Early color fadeCapped boards lighten in the first 2–3 years, then level off. Stronger here than average: UV rank #15 of 25.
- 2Gaps & fastenersBoards expand and contract with temperature — about 91 freeze–thaw days a year here; check hidden clips and end gaps every few years.
- 3Heat underfootAbout 62 days a year top 90 °F; dark composite can get uncomfortably hot in full sun. Lighter colors help.
- 4Surface mildewComposite does not rot, but pollen and dirt on shaded boards feed mildew. A wash in spring and fall prevents it.
Upkeep
Salt Lake City maintenance calendar
Built from local normals: bar width is the share of days with rain; composite mainly needs washing.
Same city, other materials
How the alternatives age in Salt Lake City
Pin-ready
Save it for when you build.
The 20-year storyboard as a tall pin, linking back to this page.
Composite decks in similar climates
Denver, CO
Albuquerque, NM
Nashville, TN
Atlanta, GA
Dallas, TX…and in very different ones
Miami, FL
Tampa, FL
New Orleans, LAQuestions Salt Lake City owners ask
How long does a composite deck last in Salt Lake City?
Our model puts a capped composite deck at 23–30 years in Salt Lake City, close to typical warranty terms. The boards outlast the look: expect some early fading and surface mildew in shade.
How often should you clean a composite deck in Salt Lake City?
Twice a year — in spring and fall. Dirt and pollen are the main thing to wash off.
Is composite worth it over cedar in Salt Lake City?
In Salt Lake City our model gives untreated cedar 16–21 years and composite 23–30. The gap is smaller where rot is slow, so upkeep preference decides.
Why does wood turn white or pale in Salt Lake City?
UV breaks down lignin at the surface; rain and wind wash the loose fibers away, leaving a bleached, silvery layer. It is cosmetic until checks open up.
Model simulation, not a guarantee: south-facing, full sun, no shade or ground-contact surprises. How it works.