Composite vs wood decking
The usual comparison is "composite costs more and lasts longer". Both halves are true and neither is useful. The decision turns on four numbers you can actually check: installed cost, joist spacing, surface temperature, and whether a damaged board can be replaced.
The numbers, side by side
| Property | Pressure-treated pine | Composite (capped) |
|---|---|---|
| Material cost per sq ft | $2.50–4.50 | $6–12 |
| Installed cost per sq ft | $15–25 | $28–45 |
| Joist spacing, 1″ board | 16″ o.c. | 12–16″ o.c. (check the board) |
| Board expansion | Minimal once dry | 1/16″ per 20°F per 12 ft |
| Surface temperature, full sun | Ambient + 20–30°F | Ambient + 30–50°F, darker colours worse |
| Maintenance cycle | Seal or stain every 1–3 years | Wash 1–2 times a year |
| Expected life | 15–25 years with maintenance | 25–30 years (manufacturer warranty 25–40) |
| Repairable? | Yes, board by board | Yes, but colour match fades |
These are US material and installed ranges for 2026 and they move with lumber prices. The ratio between the two columns is stable even when the absolute numbers are not: composite runs roughly 1.6–1.9× the installed cost of treated pine.
The joist spacing difference is not a footnote
Composite is less stiff than wood at the same thickness. A 1″ composite board at 16″ centres will sag between joists on a hot day; most manufacturers specify 12″ centres for the same span, and some require 12″ for any board installed diagonally.
That single line changes the frame. Dropping from 16″ to 12″ centres adds one joist per 4 ft of width — on a 12 × 16 deck that is about four extra joists, plus hangers, plus the labour. Budget 8–12% on the framing before you have chosen a board.
Heat is the complaint you will hear about
A dark composite board in direct sun can reach 160°F when the air is 90°F. Wood at the same moment sits around 115°F. That is the difference between a deck you can walk on barefoot and one you cannot.
Two things reduce it: a lighter colour, and a board with a lighter core. The cap stock is what takes the sun, so a light cap over a dark core still runs cooler than a dark cap. If the deck faces west and gets used in the afternoon, this is worth more attention than the warranty length.
Where the decision actually lands
Choose wood when: the deck is under 200 sq ft (the composite premium is hard to justify), the frame is already built at 16″ centres and you do not want to change it, or you want to be able to replace one board in ten years and have it look identical.
Choose composite when: the deck is large, the owner will not maintain it, the surface is in shade or partial shade, or the deck is elevated and re-staining it every other year is a genuine safety issue.
What this comparison will not name
- It does not tell you which composite. Capped, uncapped, mineral-filled and PVC boards behave differently on expansion and heat; see PVC vs composite.
- It does not price your deck. Use the cost estimator with your own dimensions.
- It does not account for climate. Freeze-thaw cycling, salt air and 100°F summers each shift the trade-off, and none of them are in the table above.
- It does not cover hidden fastener systems, which add $1–3 per sq ft and change the installation sequence for both materials.
Questions people actually ask
Is composite decking worth the extra cost?
On a deck over 200 square feet that the owner will not maintain, usually yes — the premium is roughly $13–20 per square foot installed, against $500–1,500 per re-staining cycle. On a small deck that gets a coat of stain every third year, the maths does not close.
Does composite decking get too hot to walk on?
Dark colours in direct sun can reach 160°F, which is uncomfortable barefoot. Light colours and boards with a light cap run 20–30°F cooler. Wood stays around 115°F in the same conditions.
Can I use 16 inch joist spacing with composite decking?
Only if the specific board allows it. Many require 12 inches for a 1-inch board, and nearly all require 12 inches for diagonal installation. Check the manufacturer's span table for the exact product.
How long does composite decking actually last?
The cap is the limiting factor, not the core. Warranties run 25–40 years, but fading, scratching and mould staining on the surface are common at 10–15 years and are usually excluded from the structural warranty.