Decking · Hot & dry

How a composite deck ages in Los Angeles, CA

THE SHORT ANSWER

In Los Angeles, sun is the main stress on a composite deck: UV ranks #5 of 25 cities we cover and there are about 26 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.

Main threat

Sun & UV

Climate profile

Hot & dry

Expected life

23–30 yrs

Wash

Spring & fall

Rainy days / yr

Days ≥ 90 °F

Simulated composite deck in Los Angeles, CA after 10 years

Year 10Color has lightened, then stabilizes

MODEL SIMULATION

Los Angeles, CA · capped composite boards, south-facing, full sun

Drag through time 0 — 20 years

Color lossHigh

Surface wearModerate

Mildew / rotMinimal

Fails first hereColor on full-sun boards

Storyboard

20 years in Los Angeles, washed yearly

Composite deck in Los Angeles, install: Install day — **Install**Install day

Composite deck in Los Angeles, year 1: Slight early fade — **Year 1**Slight early fade

Composite deck in Los Angeles, year 3: Color has lightened, then stabilizes — **Year 3**Color has lightened, then stabilizes

Composite deck in Los Angeles, year 5: Color has lightened, then stabilizes — **Year 5**Color has lightened, then stabilizes

Composite deck in Los Angeles, year 10: Color has lightened, then stabilizes — **Year 10**Color has lightened, then stabilizes

Composite deck in Los Angeles, year 15: Color has lightened, then stabilizes — **Year 15**Color has lightened, then stabilizes

Composite deck in Los Angeles, year 20: Color has lightened, then stabilizes — **Year 20**Color has lightened, then stabilizes

Los Angeles’s wear fingerprint

Each bar is scaled to the highest of the 25 cities we cover; the black line marks the median.

Rainy days / yr34.1 · Low

Avg humidity57.4% · Low

Decay index8.5 · Low

UV index (avg)1.5 · High

Freeze–thaw days0 · Low

Days ≥ 90 °F25.5 · Typical

NOAA station LOS ANGELES DOWNTOWN/USC (USW00093134, 5.5 km away), 1991–2020 normals · humidity & UV: NASA POWER.

What fails first here

1Early color fadeCapped boards lighten in the first 1–2 years, then level off. Stronger here than average: UV rank #5 of 25.
2Heat underfootOnly about 26 days a year top 90 °F, so surface heat is rarely an issue.
3Surface mildewComposite does not rot, but pollen and dirt on shaded boards feed mildew. A wash in spring and fall prevents it.
4Gaps & fastenersBoards expand and contract with temperature; check hidden clips and end gaps every few years.

Upkeep

Los Angeles maintenance calendar

Built from local normals: bar width is the share of days with rain; composite mainly needs washing.

Jan

Feb

MarWash & check for mildew

Apr

May

Jun

Jul

Aug

Sep

OctWash, clear gaps

Nov

Dec

Same city, other materials

How the alternatives age in Los Angeles

Cedar deck

Expected life here: 18–24 yrs · main threat: sun & uv

See it age in Los Angeles →

Wood fence

Expected life here: 16–21 yrs · main threat: sun & uv

See it age in Los Angeles →

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The 20-year storyboard as a tall pin, linking back to this page.

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Pinterest storyboard: composite deck in Los Angeles, CA, new to year 20

Composite decks in similar climates

…and in very different ones

New Orleans, LA

Buffalo, NY

Miami, FL All 25 cities →

Questions Los Angeles owners ask

How long does a composite deck last in Los Angeles?

Our model puts a capped composite deck at 23–30 years in Los Angeles, 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 Los Angeles?

Twice a year — in spring and fall. Dirt and pollen are the main thing to wash off.

Is composite worth it over cedar in Los Angeles?

In Los Angeles our model gives untreated cedar 18–24 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 Los Angeles?

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.