Decking · Composite decking (wood-plastic)
How long does composite decking last?
InterNACHI's baseline chart puts composite decking at 8 to 25 years — an unusually wide band on a chart that mostly deals in single figures, because the uncapped boards of the 1990s and today's capped ones are barely the same product. Trex's warranty runs 25, 35 or 50 years depending on the line. Read the second table in that document and the payout starts shrinking at year eleven.
Updated
The gap: warranty ends at 25 years; typical service life ends around 25 years. The paper and the typical service life end together — an unusually honest term. Warranty document (Trex, checked 2026-08-27)
Typical service life: 8–25 years
The baseline chart's "8 to 25" spans the whole category, from early uncapped wood-flour boards that took on moisture and grew mould to the capped boards sold now. TimberTech's own literature estimates 25 to 30 years for composite — the maker's figure, and one no capped board has been on a deck long enough to test.
Tier 3 · baseline chart (undated) Range from InterNACHI — Standard Estimated Life Expectancy Chart for Homes, checked 2026-08-27.
Heat and light move this material more than moisture does. The same board that holds its colour for decades on a shaded northern deck will be measurably faded in a few seasons of high desert sun — which is why the fade clause is written as a numeric colour threshold rather than a promise not to fade. A window wall throwing concentrated reflected sun onto one strip of deck can distort boards there while the rest of the deck is untouched.
What the warranty paper actually says
Trex (Enhance decking and fascia (25-year residential term; Select 35 years, Transcend 50)) publishes a 25-year limited, prorated, transferable, conditional warranty. Two promises sit in one document. Physical integrity: the board will not split, splinter, rot or take structural damage from termites or fungal decay. Fade: colour will shift no more than 5 Delta E for twenty-five years — and on the longer 35- and 50-year lines, no more than 15 Delta E for every year after that, a threshold three times looser than the one it replaces. From year eleven the money is prorated on a published table: on the 25-year term that is 80% at year 11, 20% at year 20 and 10% at years 23 through 25. Trex pays for boards or refunds their price, never removal, installation, labour or freight. One transfer is allowed and only inside the first five years. Puncturing or painting the surface voids it outright, contact with heat over 275°F is excluded, and fading or staining on the underside and the cut ends is not covered at all.
The warranty document itself , checked 2026-08-27.
What shortens it
- Sustained rooftop-grade heat and sun on south and west exposures, which drives the fade the warranty measures in Delta E units
- Reflected and concentrated sunlight off low-emissivity window glass, a documented cause of surface distortion that every major composite warranty excludes
- Gapping tighter than the installation guide calls for, which leaves the boards nowhere to move as they expand and contract
- Debris packed between boards and against the ledger, holding moisture against a core that is still part wood flour
- Grease, rust from metal furniture feet, and de-icing chemicals — all named exclusions rather than covered stains
Signs of wear to look for
- Colour drifting unevenly across the deck, with the shaded strip under a table or planter noticeably darker than the field
- Chalky, dulled surface where the cap has thinned, often first at the traffic path from the door
- Mould speckling in the grooves and along board edges, particularly on shaded and north-facing decks
- Scratches and scuffs that stay bright instead of weathering in, because the cap does not re-form
- Board ends and cut edges swelling, darkening or flaking where the uncapped core is exposed
Composite boards are a surface, not a structure: bounce underfoot, a sagging span, or movement where the deck meets the house belongs to the frame — that is an inspection question, not a web-page question.
Other decking materials
- Pressure-treated pine about 15 yrs
- PVC decking (cellular PVC) 50+ yrs
- Western red cedar 15–25 yrs
- Redwood 10–30 yrs
- Ipe 25+ yrs