Composite vs Wood Decking: Total Cost of Ownership

Installed cost is where the gap looks widest and where it is most often misread. Composite decking is roughly two to three times the price of treated pine per board, but the framing beneath is identical pressure-treated timber and the labour is broadly the same. Across the whole build the gap narrows to something closer to 1.8 times, which is still substantial but less dramatic than a board-price comparison suggests.

Maintenance is where they diverge permanently. Wood needs cleaning and resealing on a two-to-four-year cycle: materials for a 320 square foot deck run to a couple of hundred dollars, and the labour is a full weekend if you do it yourself or several hundred dollars if you do not. Composite needs washing, which is an hour with a brush and a bucket once a year.

Lifespan follows from maintenance. A well-kept wood deck reaches fifteen years and sometimes twenty; a neglected one is often finished at ten. Composite reaches twenty-five to thirty largely regardless, because there is nothing to neglect.

Then there is replacement. Over a twenty-five year horizon, a wood deck is typically bought twice and a composite deck once — and the second wood deck arrives with its own demolition and disposal cost, which is routinely left out of comparisons.

This is the input that decides the comparison, and it is the one every published version assumes away.

Refinishing a deck properly means cleaning it, letting it dry thoroughly, sanding where the finish has failed, and applying two coats — with a dry weather window at both ends. For a 320 square foot deck that is a solid weekend, and it comes round every two to three years for as long as you own the house. Over twenty-five years that is eight or nine weekends.

If you will genuinely do that, wood is frequently the cheaper option over any horizon, and the tool will say so. If you will not, then the fifteen-year lifespan in every brochure does not apply to your deck, and the comparison shifts sharply toward composite. Neither answer is wrong; they are answers to different questions.

The tool models this directly. Selecting the neglectful option shortens wood's modelled life by about a third, which is a fair reflection of what happens to unsealed softwood outdoors. It is deliberately unflattering, because a comparison that assumes perfect maintenance is not a comparison most people can use.

Composite is not simply better. There are several situations where wood is the correct choice and the arithmetic supports it.

Short ownership. If you are selling within five to eight years, the composite premium is money you spend and largely hand to the next owner. Published cost-versus-value studies put deck recoup at roughly half to two thirds, so unused life is worth something at sale but never its full replacement cost.

Heat. Composite absorbs and holds far more heat than wood — a dark composite deck in full afternoon sun can become genuinely too hot for bare feet, and that is not something you can fix afterwards. On a south-facing deck in a hot climate, that alone can settle it.

Repairability. A scratched or stained wood board sands out. A scratched composite board is scratched permanently, and matching a replacement board to weathered neighbours years later is difficult because the colour has moved.

And appearance, which is not a small consideration on something you look at every day. Cedar left to grey naturally is a look composite approximates rather than achieves.

One thing worth understanding about any long-horizon comparison is that costs are lumpy rather than smooth, and the totals swing depending on exactly where your horizon falls relative to a replacement.

If your ownership period ends two years after a deck was replaced, you have paid for a whole deck and used almost none of it. You will recover part of that at sale, but not most of it. The tool accounts for residual value at a default sixty per cent recovery, matching published cost-versus-value figures, and it flags the situation explicitly when a replacement lands near the end of your horizon.

In practice most people faced with that situation repair rather than replace: a few boards, a section of railing, a thorough clean. That is usually the right call and it is worth pricing before treating any long-horizon number as settled.