Decking · 25 cities

How long does a pressure-treated deck last?

Typically 10–15 years, but climate moves that a lot. In our model a pressure-treated deck left unsealed lasts 9–11 years in Denver, CO and 12–15 years in Las Vegas, NV; the median city gets about 13 years. Sun & UV is the main threat in 12 of 25 cities. Sealing every 2–3 years stretches it to 11–21 years.

Simulated pressure-treated deck in Seattle, WA after 10 years
Year 10Decay starting at board ends, heavy mildew, deep checks
MODEL SIMULATION
Seattle, WA · treated southern pine boards, south-facing, full sun, no sealant
Color lossSevere
Surface checkingSevere
Mildew / rotHigh
Fails first hereCut ends that lost their treatment, and joists

Every city

Expected life by city

Sorted shortest-lived first. Treated southern pine boards, south-facing, full sun, no sealant.

CityYear 10Expected lifeMain threatClimate profileDecay index
Denver, CO9–11 yrsFreeze–thawCold, hard freeze–thaw34.2
Mobile, AL9–11 yrsMoisture & decayHot & humid110.2
Miami, FL9–11 yrsSun & UVHot & humid155.8
Tampa, FL9–11 yrsSun & UVHot & humid103.6
Albuquerque, NM9–12 yrsSun & UVDry & sunny22.2
New Orleans, LA9–12 yrsSun & UVHot & humid100.9
Atlanta, GA9–12 yrsMoisture & decayMixed79.5
Salt Lake City, UT10–13 yrsFreeze–thawCold, hard freeze–thaw23.3
Austin, TX10–13 yrsSun & UVMixed53.9
Houston, TX10–13 yrsSun & UVHot & humid84.5
Charleston, SC10–13 yrsMoisture & decayHot & humid73.7
Nashville, TN10–13 yrsMoisture & decayMixed70.7
Dallas, TX11–14 yrsSun & UVMixed47.4
Chicago, IL11–14 yrsFreeze–thawMixed55.3
Minneapolis, MN11–14 yrsFreeze–thawMixed47.2
Buffalo, NY11–14 yrsFreeze–thawMixed52.8
New York, NY11–14 yrsMoisture & decayCool & damp59.5
Boston, MA11–14 yrsFreeze–thawMixed48.3
Portland, OR11–15 yrsMoisture & decayCool & damp56.6
Phoenix, AZ11–15 yrsSun & UVHot & dry7.2
Seattle, WA12–15 yrsMoisture & decayCool & damp52.6
San Francisco, CA12–15 yrsSun & UVCool & damp26.7
Los Angeles, CA12–15 yrsSun & UVHot & dry8.5
San Diego, CA12–15 yrsSun & UVHot & dry12
Las Vegas, NV12–15 yrsSun & UVHot & dry0.4

Model estimates from 1991–2020 climate normals. Methodology.

Pressure-treated deck lifespan: common questions

How long does a pressure-treated deck last?

Typically 10–15 years, but climate moves that a lot. In our model a pressure-treated deck left unsealed lasts 9–11 years in Denver, CO and 12–15 years in Las Vegas, NV; the median city gets about 13 years. Sun & UV is the main threat in 12 of 25 cities. Sealing every 2–3 years stretches it to 11–21 years.

What makes a pressure-treated deck wear out faster?

In our model: sun and UV (main threat in 12 cities), moisture and decay (main threat in 7 cities), freeze–thaw (main threat in 6 cities). Shade, ground contact and planters that keep wood wet shorten life further.

How do you know a pressure-treated deck needs replacing?

Probe board ends, joists and stair stringers with a screwdriver: if it sinks in easily, the wood is rotting. Other signs are boards that flex or split, fasteners that no longer hold, and spongy spots underfoot.

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