Decking · Mixed

How a cedar deck ages in Dallas, TX

THE SHORT ANSWER

In Dallas, sun does most of the damage. UV here ranks #12 of 25 cities we cover, with about 108 days a year above 90 °F. Untreated boards bleach to a pale silver and open up surface checks; with a decay index of only 47.4, rot is a slow, secondary risk. Model estimate: 15–19 years untreated, 20–26 years sealed on schedule.

Main threat

Sun & UV

Climate profile

Mixed

Expected life (untreated)

15–19 yrs

Fully gray by

Year 2

Best seal window

Jul – Aug

Sealed on schedule

20–26 yrs

Simulated cedar deck in Dallas, TX after 10 years

Year 10Heavy mildew, deep checks

MODEL SIMULATION

Dallas, TX · south-facing deck, full sun, no sealant

Drag through time 0 — 20 years

Color lossSevere

Surface checkingSevere

Mildew / rotHigh

Fails first hereSun-facing board ends and surface fibers

Storyboard

20 years in Dallas, untreated

Cedar deck in Dallas, install: Fresh boards — **Install**Fresh boards

Cedar deck in Dallas, year 1: Silvering begins — **Year 1**Silvering begins

Cedar deck in Dallas, year 3: Surface checks — **Year 3**Surface checks

Cedar deck in Dallas, year 5: Mildew in shade, surface checks — **Year 5**Mildew in shade, surface checks

Cedar deck in Dallas, year 10: Heavy mildew, deep checks — **Year 10**Heavy mildew, deep checks

Cedar deck in Dallas, year 15: Soft spots — probe for rot, heavy mildew, deep checks — **Year 15**Soft spots — probe for rot, heavy mildew, deep checks

Cedar deck in Dallas, year 20: Soft spots — probe for rot, heavy mildew, deep checks — **Year 20**Soft spots — probe for rot, heavy mildew, deep checks

Dallas’s wear fingerprint

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

Rainy days / yr82.2 · Low

Avg humidity69.2% · Low

Decay index47.4 · Typical

UV index (avg)1.4 · Typical

Freeze–thaw days21.8 · Typical

Days ≥ 90 °F107.6 · High

NOAA station DALLAS FAA AP (USW00013960, 7.3 km away), 1991–2020 normals · humidity & UV: NASA POWER.

What fails first here

1Surface checkingStrong UV (rank #12 of 25) dries and shrinks the surface faster than the core, opening fine cracks.
2Mildew & algaeFrequent rain and 69% average humidity keep shaded boards damp; dark spots start near walls, planters and gaps.
3Sun bleaching & raised grainSurface fibers break down under strong sun and wash away, leaving a pale, fuzzy texture.
4Rot at board ends & joistsSlow here (decay index 47.4), but ends and joists under planters still fail first.

Upkeep

Dallas maintenance calendar

Built from local normals: bar width is the share of days with rain; sealant needs 2–3 dry days between 50 and 88 °F.

Jan

Feb

MarInspect ends & fasteners

Apr

May

JunWash off mildew

JulSeal / stain

AugSeal / stain

Sep

OctClear leaves & gaps

Nov

Dec

Same city, other materials

How the alternatives age in Dallas

Composite deck

Expected life here: 23–30 yrs · main threat: sun & uv

See it age in Dallas →

Wood fence

Expected life here: 14–18 yrs · main threat: sun & uv

See it age in Dallas →

Pin-ready

Save it for when you build.

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

Save to Pinterest Download pin

Pinterest storyboard: cedar deck in Dallas, TX, new to year 20

Cedar decks in similar climates

…and in very different ones

Buffalo, NY

Seattle, WA

Denver, CO All 25 cities →

Questions Dallas owners ask

How long does a cedar deck last in Dallas?

Our model puts it at 15–19 years untreated and 20–26 years if it is sealed every 2–3 years. The national typical range is 15–20 yrs; Dallas’s sun & uv profile is why the local number differs.

When is the best time to seal a cedar deck in Dallas?

July and August: the months with the fewest rainy days while average temperatures sit between 50 and 88 °F. Most sealants need 2–3 dry days to cure.

Is composite better than cedar in Dallas?

It depends: composite won’t check or bleach, but it fades and gets hot in strong sun. Our model gives composite 23–30 years here versus 15–19 for untreated cedar.

Why does wood turn white or pale in Dallas?

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.