Composite deck cost
Composite costs roughly 1.7 times treated pine installed, and the maintenance saving over 20 years is real but smaller than the sales pitch. Here is the arithmetic without the marketing.
The material lines
| Item | Per sq ft | Note |
|---|---|---|
| Composite decking | $6–12 | Capped boards at the top of the range |
| Hidden fasteners | $1–3 | Clips, screws and a setting tool |
| Extra joists for 12″ centres | $2–4 | Only where the board requires it |
| Fascia and trim | $1–2 | Composite fascia to match |
| Labour | $10–15 | Similar to wood, slightly faster on the surface |
Installed, that lands at $28–45 per square foot. On a 240 sq ft deck: $6,700–10,800.
The four extras that surprise people
- Joist spacing. Many 1″ composite boards need 12″ centres, not 16″. On a 12 ft wide deck that is four extra joists per bay plus hangers — 8–12% on the framing.
- Hidden fasteners. They are not optional on most capped boards, and at $1–3 per square foot they are 5–10% of the decking cost.
- Fascia. The board edge has to be finished, and composite fascia costs $15–30 per linear foot.
- Stair treads and fascia are priced per piece, not per square foot, which makes stairs disproportionately expensive.
The maintenance arithmetic, honestly
A treated pine deck needs a clean and a re-stain every 2–3 years. Materials for a 240 sq ft deck: $150–300. If you do it yourself, that is a weekend every third year. If you pay someone: $600–1,200 per cycle.
Over 20 years, at every three years: six cycles, so $900–1,800 in materials if you do it yourself, or $3,600–7,200 hired out.
The composite premium over treated pine on the same deck is roughly $3,000–5,000 installed. So:
- If you hire the staining out: composite pays back in 12–18 years, plus it saves the disruption.
- If you do it yourself: it does not really pay back on cash — you are buying back six weekends.
That is the honest version. The pitch often compares composite to a deck that is never maintained, which is not the same comparison.
What actually drives the decision
For most buyers it is not payback. It is one of these three:
- They will not maintain it. A neglected wood deck is a safety issue at 15 years; a neglected composite deck is fine.
- The deck is elevated and re-staining it means working at height every third year.
- They want a specific look that only composite provides.
All three are legitimate. "It pays for itself" is the weakest of the arguments, and it only holds if you were going to pay someone to stain.
Where the cost model breaks
- It does not price your deck — use the cost estimator.
- It does not compare brands. Board quality varies more within the category than between categories.
- It does not include railing, which is a separate line at $25–75 per linear foot.
- It does not account for resale value, which is local and not reliably measurable.
Questions people actually ask
How much does a composite deck cost?
Installed, $28–45 per square foot, or $6,700–10,800 for a 240 square foot deck. That is roughly 1.7 times the cost of pressure-treated pine.
Does composite decking pay for itself?
Only if you would have paid someone to re-stain every few years. The premium is $3,000–5,000 on a typical deck, and hired-out staining runs $600–1,200 per cycle, so payback is 12–18 years.
What hidden costs come with composite decking?
Hidden fasteners at $1–3 per square foot, extra joists when the board requires 12-inch centres, matching fascia at $15–30 per linear foot, and higher per-piece costs on stairs.
Is composite cheaper than wood in the long run?
It can be, over 20 years, if maintenance is hired out. On first cost it is 1.7 times more, and that gap does not close for most DIY owners.