The 25-Year Deck Cost — Total Cost of Ownership

For most owners, yes, once maintenance and replacement are in the calculation. The three costs of owning a deck are the build, the upkeep and the eventual replacement, and shoppers routinely compare only the first. Composite costs more on day one and then asks for washing at about $0.05 per square foot a year, roughly $16 annually on a 320 square foot deck, or about $400 across 25 years. Pressure-treated is cheap to build and then wants re-staining every couple of years at about $0.45 per square foot, roughly $144 a year or $3,600 over the same period, and its surface typically reaches end of life inside the window and gets rebuilt once. That $3,200 maintenance gap plus one surface replacement is what inverts the ranking. The exception is a short holding period, where you simply never reach the years that make composite cheaper.

About 10 to 15 years for the walking surface with regular staining, and materially less if the staining slips. The framing is a different question and usually outlives the boards: ground-contact-rated joists and beams that stay dry and ventilated can go well beyond that, which is why a pressure-treated deck rebuild is normally a surface replacement rather than a demolition to the footings. That distinction matters for budgeting, because replacing boards on sound framing is far cheaper than starting again. Plan on one such replacement inside a 25-year horizon, and remember it costs more than the boards: you are paying to tear off the old surface, dispose of it, and pay labour a second time. Keeping the surface sealed and the framing ventilated is what pushes a pressure-treated deck toward the top of that 10 to 15 year range rather than the bottom.

Capped composite, for most homeowners. It is expensive to build and then almost free to keep: washing only, at about $0.05 per square foot a year, with a 25 to 30 year service life and no mid-life surface replacement. Across a 25-year horizon on a 320 square foot deck that combination usually produces the lowest total of any material here. PVC is comparable and pulls ahead specifically around pools and on the coast, where constant moisture is hardest on anything with wood fibre in it, and it carries the longest service life at 30 years or more. Cedar sits in the middle: roughly 20 to 25 years with diligent upkeep at about $0.35 per square foot a year. Pressure-treated is cheapest only over a short horizon, which is a real scenario rather than a consolation.

Roughly $0.45 per square foot a year for pressure-treated, about $0.35 for cedar and about $0.05 for composite or PVC. On a 320 square foot deck that is about $144 a year for pressure-treated against about $16 for composite, and the gap compounds every year you own it. Those figures cover materials rather than your weekends: pressure-treated needs cleaning, brightening and re-staining roughly every two years, cedar every three, and composite needs a wash with mild detergent. If you pay someone to do the staining rather than doing it yourself, the wood numbers rise substantially and the comparison tilts further. This single line is the heart of lifetime deck economics, because it is small enough to ignore in any one year and large enough over 25 to outweigh the difference in build cost between the materials.

Start by inspecting the structure rather than the surface, because that is what decides it. If the framing, ledger, footings and fasteners are sound and only the boards look tired, refinishing or replacing the surface is far cheaper than a rebuild: sanding and re-staining timber, or laying new boards on the existing joists, keeps the expensive parts of the deck in service. If the ledger flashing has failed, the joists are soft where you probe them, or the footings have moved, replacement is the honest answer, because a new surface over compromised framing hides the problem rather than fixing it. One caveat applies when refitting composite onto old framing: the joist spacing must meet the manufacturer's requirement, 16 inches on centre parallel and 12 inches diagonal, so a deck framed at 24 inches needs additional joists before new boards go down.

It should, and the deciding variable is how long you will own the deck rather than which material is theoretically best. Owning about five years, optimise for upfront price, and pressure-treated is a rational choice: you will not be there for the maintenance years or the replacement, and the cheapest deck you can build now beats the better one you cannot afford. Owning 15 years or more, optimise for lifetime cost, and composite or PVC almost always wins once maintenance and replacement are counted. The common and expensive mistake is the mismatch: buying pressure-treated to save on day one for a deck you intend to keep for two decades, then paying for it in stain every other year and a rebuild around year 12. Match the material to the time horizon and the arithmetic mostly takes care of itself.