How long does composite decking last? Lifespan and what warranties really cover

A composite deck can only last as long as the frame under it, so I'd judge the boards and the frame together. The boards carry warranties from 10 to 50 years for a house deck¹, and the owner reports cited here run to thirteen years. The warranty is a narrower promise than the number on the box suggests, so read what it pays for before you lean on it.

How long does composite decking last in practice?

The owner reports cited here are far short of thirty years on a capped deck, and one Australian maker only launched its capped range in 2019⁶. What there is, is owners posting about decks between four and thirteen years old.

The good reports cover a mix of boards. On Whirlpool in December 2025, WhoMastadon wrote that a Trex deck built about ten years earlier "still looks exactly the same"¹³. An Ekodeck owner in northern New South Wales wrote on ProductReview five months ago that a deck laid in 2013, facing the western sun, was "still in excellent shape" after two or three cleans, with some fading⁹. In 2017 johnw2003 said a six-year-old composite deck looked the way it did on the day it went down and hadn't needed any work¹⁵. In 2024 crozzb described two decks built from the least expensive boards they could find on eBay, seven years old with one wash-down in that time¹⁴.

The poor reports are about boards that split or went mouldy within about ten years, and boards that faded. A ModWood owner on ProductReview wrote six months ago that their deck around a pool, laid more than ten years earlier, began to warp and split at about eight or nine years, and that the boards shrank enough to leave gaps at the joins⁸. Those were Jarrah boards, a colour from the maker's Natural Grain range and not its capped one. On Whirlpool in 2016, 5Oswald said a four-year-old ModWood deck "has split and has gone mouldy" while two Millboard decks built six months later still looked new¹². An Ekodeck Classic owner in south-east Queensland wrote a year ago that five years in, the deck hadn't stood the test of time, with black mould on boards that stay wet and colour washing out⁹. Capped boards fade too. A NewTechWood owner in Melbourne wrote nine months ago that boards laid during the pandemic had faded¹¹, and that maker caps its boards on all four sides.

On that evidence I'd plan around the warranty term for a capped board on a sound, well-ventilated frame. I'd expect an uncapped board in a damp, shaded spot to look tired well before its term is up, even while it's still sound.

The frame decides the real lifespan

The boards are only as steady as the frame, and every warranty cited here excludes damage caused by movement or settling of the structure under the boards¹. If the frame moves, what happens to the boards isn't the maker's problem. One Ekodeck owner on ProductReview had to lift boards near the front door to replace a support underneath that had gone soft, about four and a half years after that section went down⁹.

So I'd match the frame to the board. Use H3 pine above ground and H4 where timber meets the ground, seal every cut end and tape the joist tops, as set out on the treated pine framing page and in H3 or H4 treated pine under a composite deck. If the deck is low to the ground or in a termite area, I'd look hard at a steel frame, and steel vs timber deck frames sets out the trade-offs. Thinking of keeping an old frame? Read composite decking on an existing deck frame first.

What the warranty years actually cover

Every composite warranty cited here is a defects warranty first. It promises that the board itself won't fail from a short list of causes within the term. One Australian warranty limits a material defect to a short list that includes rot and termite damage². Another promises the board won't "split, rot, splinter or suffer structural damage"³. A third covers warping and cracking as well⁵.

For a house deck, the terms in the documents cited here run from 10 years, on one uncapped range⁵ and one hollow capped range⁴, to 25 years on most capped ranges². One American maker sold here goes to 35 years on its mid-range line and 50 on its top line¹. Commercial use usually gets 10 years, and one warranty treats a rented or leased house as outside residential use, which puts a deck on an investment property on that shorter term².

Fade and stain cover is a separate promise, and only some capped ranges have it. Where it exists, the board is warranted not to shift by more than 5 Delta E on a colour scale¹. Food and drink stains are covered only if you clean them within the time allowed, which is a week in one document¹ and 72 hours in another⁵. I've gone into the fade terms in fading and scratches, and into the cap itself in capped vs uncapped composite decking.

What the fine print excludes

The exclusions run longer than the cover. These come up in most of the documents I read:

• Scratches, gouges and anything from impact².
• Mould and mildew, and staining from dirt or grease³. One warranty caps mould claims at two years whatever the term³.
• Natural colour change and weathering, on any range without a specific fade warranty⁵.
• Installation outside the maker's guide, including the wrong joist centres or fasteners the maker hasn't approved².
• Paint or any other coating, which voids one warranty outright².
• Heat from fire pits and barbecues⁷, and sunlight reflected off low-E glass windows².
• Static build-up, which one maker says it doesn't warrant against at all³.

The installation exclusion is the one I'd worry about most, because it's the one in your hands. One warranty is void unless the boards were installed to the maker's guidelines, so boards laid on joist centres wider than the guide allows lose their cover from the day they go down. Keep the invoice and the install guide you worked from, and photograph the frame before the boards go on.

Pro-rata terms and what you'd get back

A long warranty is a declining one. Most of the documents cited here pay in full for about the first ten years and then step down. One pays 80 per cent of what you paid in years ten to thirteen and keeps stepping down to 10 per cent in the last three years of a 25-year term², and another uses the same steps³. A third uses those steps south of the Tropic of Capricorn, but north of it what you can recover starts at 50 per cent in year eleven and falls to 5 per cent from year twenty⁵. If you live in the tropics, that table matters. A fourth takes 4 per cent off the refund for every full year since purchase⁷.

Labour and freight are almost never in the figure. The remedy is replacement boards or part of what you paid for them, and the maker chooses which³. Lifting the old boards and laying the new ones is left to you. One maker says it may contribute to labour on a valid claim in the first six years, at its discretion⁷. That's the only labour wording in the documents cited here.

Replacement boards may not match, either. Three of the documents say the maker will match colour as closely as it reasonably can but doesn't guarantee it².

Claims, registration and transfers

Most of the warranties want written notice within 30 days of finding the problem, with photos and proof of purchase³. One requires you to register online within 90 days of purchase or the warranty never starts⁷. Don't remove or repair anything until the maker has answered in writing, because under one document you won't qualify for a refund if you do².

Transfers vary. Some warranties can be passed once to a buyer of the house within five years of the original purchase¹. One Australian maker's warranties can't be transferred at all³. If you're buying a house with a composite deck, ask for the receipt and the warranty document, because a claim needs proof of purchase.

Claims do get refused. A Trex owner in south-east Queensland wrote on ProductReview four years ago that after a long exchange of emails, the company called a white-grey discolouration a "dirty deck" situation, not covered by the warranty¹⁰. Another Trex owner wrote five years ago that the company blamed them for a deck that never looked clean, offered a replacement, then made it conditional on another round of cleaning¹⁰. The only offer the ModWood owner above received was replacement material at the maker's own rate plus delivery, which they turned down.

Under the Australian Consumer Law you have guarantees that a maker's warranty can't take away, and the Australian documents cited here say so². If a claim is refused and you think the board was faulty, that's the route I'd take. The Ekodeck Classic owner above wrote that they had asked the ACCC and Queensland's Office of Fair Trading for advice.

Before you order

Download the actual warranty document for the range, not the summary on a retailer's page, and read the exclusions and the pro-rata table. Check whether fade cover exists for that range, whether the deck counts as residential if the house is ever rented out, and whether the table changes north of the Tropic of Capricorn. Build the frame to the install guide and keep the evidence. Then weigh the term against the frame's likely life, and if the two are badly mismatched, I'd spend the money on the frame before a longer board warranty. Is composite decking worth it? covers the money side of that decision. The brand pages link each maker's warranty document, and the deck designer will give you a materials list for a frame at the right centres for the board you choose.