Your decking choice is the one everyone has an opinion on — and the one you live with the longest. Pressure-treated, cedar, composite, and PVC each trade off price, upkeep, looks, and lifespan differently in Ontario’s freeze-thaw climate. Below we settle the composite vs wood question and answer the nine material questions homeowners ask most. This page is part of our complete guide to building a deck in Ontario.

Composite vs wood: which decking for Ontario?

Answer three quick questions for a recommendation, then compare the details below.

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Composite vs pressure-treated for Ontario weather — which?

Both survive Ontario’s freeze-thaw, but they trade off. Pressure-treated is cheapest and easy to work, but it warps and needs staining every 1–2 years. Composite costs more upfront, won’t splinter, holds its colour, and skips the staining. Keeping the deck long-term and hate maintenance? Composite usually wins. Tight budget? PT.

Every decking material compared

Cedar vs PT vs composite vs PVC — pros, cons & lifespan

Roughly, by upfront board cost and lifespan: pressure-treated about $3–5/sq ft and 15–20 years; cedar $5–8 and 15–25 years; composite $6–12 and 25–30+ years; PVC $9–15 and 30+ years. Wood is cheaper but needs sealing; composite and PVC cost more but skip the upkeep.

Board cost is material only — installed deck cost is higher; see the cost to build a deck guide. Whatever you pick, keep it looking new with the deck maintenance guide.

Does composite get too hot to walk on barefoot?

It can. Dark composite boards in full sun get hotter than wood and can be uncomfortable barefoot. If your deck faces south with no shade, choose a lighter colour or a line engineered to stay cooler, and sample-test a board on a hot day before you commit to a dark one.

Composite regrets — fading, mould, or warping?

Modern composite is good, not magic. Cheaper, older, or uncapped boards can fade, grow mould in damp shade, or scratch. Capped composite resists all three far better. Buy a quality capped line, keep it clean, and give it airflow and drainage underneath to avoid the common regrets.

Wood: cupping, gaps and stain

My new PT boards shrank, cupped or gapped — what went wrong?

New pressure-treated lumber is usually wet from the treatment, so it shrinks, cups, and gaps as it dries — that’s normal. Install it reasonably tight (it shrinks apart on its own), lay boards bark-side up so they cup away from water, fasten well, and let it dry out before you stain.

How big a gap between deck boards?

Gap wet PT boards tight (about a 1/8 inch, a nail’s thickness) since they shrink as they dry; gap dry boards and composite about 1/8–1/4 inch for drainage and expansion. Always follow the composite manufacturer’s exact spacing — end gaps for composite are often larger for thermal movement.

Best stain for a wood deck, and how often?

For PT and cedar, use a penetrating semi-transparent stain — it wears away instead of peeling like film-forming products. Refresh every 1–2 years, sooner on south-facing or lakefront decks. Let new pressure-treated lumber dry for weeks to months before the first coat.

Staining is the bulk of a wood deck’s upkeep — the full routine, plus winter and cleaning tips, is in our deck maintenance guide. Shop deck stain →

Fastening and framing for your boards

Hidden fasteners vs screws — which?

Hidden clips give a clean, screw-free surface and are common with grooved composite; face-screwing is faster, cheaper, and easy to repair. Both pass code. Match the system to your board — many composites are designed for hidden fasteners — and use the manufacturer’s recommended clips.

• Hidden clips — clean look, no surface screws; best with grooved composite/PVC boards.
• Face screws — cheaper and faster; easiest to lift a board later for a repair.
• Match the metal — whatever the method, use treated-lumber-rated stainless or coated fasteners.

Shop hidden fasteners →

What screws are safe for PT lumber?

Use only hot-dip galvanized or stainless fasteners rated for treated lumber. Modern PT is corrosive to plain steel and standard zinc, which rust fast and stain the wood. For composite, use the manufacturer’s colour-matched screws or hidden-clip screws — also stainless or specially coated.

Can I put composite on a PT frame? What joist spacing?

Yes — composite decking goes on a standard pressure-treated frame; the frame is the structure, the composite is just the surface. The catch is joist spacing: many composite boards require 12-inch on-centre joists (especially diagonal layouts) as a warranty rule. Confirm the spacing before you frame.

That 12-inch requirement changes your whole framing layout, so settle your board first, then size the structure with the framing & spans guide.

Frequently asked questions