Composite vs pressure-treated. Honest math.

Every 2–3 years is the realistic schedule for a Saskatchewan pressure-treated deck. The Prairie freeze-thaw cycle accelerates UV silvering and surface checking — homeowners who stretch to year 4–5 between coats see noticeably faster failure. Cost per application: $300–$600 in product on a 320 sq ft deck plus a full weekend of labour. Penetrating oils like Cutek Extreme outperform film-forming stains in our climate because they don't peel under freeze-thaw expansion.

Surface boards typically last 10–15 years in Saskatchewan before splintering, cracking, and stain wash-out demand replacement. The framing underneath (also pressure-treated) often outlasts the surface by 5–10 years if it stayed dry — so a typical pattern is one full deck build, then a surface-only resurface around year 12–15, then a full rebuild around year 25. Aggressive maintenance can extend the surface to 18–20 years; skipped maintenance shrinks it to 8–10. Capped composite carries 25–50 year residential warranty for comparison.

Composite residential warranties typically cover 25–50 years and protect against material defects, fade beyond a defined Delta-E threshold, splitting, peeling, and structural failure under normal residential use. Major brands TUDS stocks: Eva-Last 25–50 yr, Trex 25–50 yr, Fiberon 25–50 yr, Deckorators 25–50 yr. Pressure-treated warranties are typically 1–5 years from the treating company against rot and termites only — surface failure (splintering, checking, fade) isn't covered. The vendor owns the claim process in both cases; TUDS helps you navigate but doesn't file claims on your behalf.

Composite runs moderately warmer than pressure-treated in direct sun — varies meaningfully by colour. Light-coloured composite (greys, light browns, weathered-cedar tones) reads close to wood underfoot. Dark composite (espresso, ebony, charred-walnut) reads noticeably warmer than wood at peak summer heat — barefoot-comfortable in the morning and evening, hot at 2pm in July. If barefoot comfort matters, stick to lighter cap colours regardless of brand. Capped polymer / PVC tends to dissipate heat faster than capped composite of equivalent colour. None of the materials are unsafe — it's a comfort question, not a safety one.

Usually yes. The framing under most PT decks is itself pressure-treated and tends to outlast the surface boards by 5–10 years. If the joists are sound (no rot, no significant warping, and joist spacing matches your composite brand's spec — typically 12" or 16" on-centre), you can resurface in composite over the existing frame. A composite resurface costs roughly $35–$70 per sq ft (no demo, no new piers) vs $60–$120 per sq ft for a full rebuild. Bring photos of the joists and a tape measure to either showroom and we'll tell you what's salvageable. Some composite brands require closer joist spacing than PT decks were typically built for — a sister-joist retrofit can solve it.

Pressure-treated uses copper-based preservatives — modern Canadian PT (post-2003) is ACQ, MCA, or CA-B. Less toxic than the older CCA (which contained arsenic) but still chemicals: don't burn the scraps, don't compost the sawdust, use gloves when cutting. Composite is typically 50–95% recycled content — recycled wood fibre from sawmill waste plus recycled plastic (HDPE, PE, or PP) from grocery bags and milk jugs, with a virgin polymer cap. Major brands divert hundreds of millions of pounds of plastic from landfill annually. End of life: PT is hazardous waste in most municipalities; composite is increasingly recyclable through manufacturer take-back. On most environmental metrics composite is the greener answer in 2026 — neither is perfect.

On a typical 320 sq ft Saskatchewan deck (mid-tier on each material): Pressure-treated 20-year total: roughly $20,000–$22,000. That's $13,000 install + 7 refinishes × $450 each ($3,150) + a partial surface-board replacement around year 12–15 ($4,000–$6,000). Composite 20-year total: roughly $28,000–$30,000. That's $28,800 install + zero maintenance + zero replacement. Net delta: composite costs $7,000–$9,000 more over 20 years — roughly $350–$450 per year for zero stain weekends and a deck that always looks new. Full Canadian deck cost guide for ranges across all materials.

Pressure-treated wood is rated for ground-contact and freeze-thaw exposure — it'll structurally survive Saskatchewan winters for 15–25 years on the framing side. The challenge is the surface boards, where freeze-thaw cycles drive water in and out of the grain, accelerating splintering, checking, and stain failure. Typical Saskatchewan PT deck surface life: 10–15 years with regular stain. Composite cap doesn't absorb water, so freeze-thaw is a non-event for the surface. Both materials need frost-rated footings (1.2 metre / 4 ft deep on the Prairies) regardless of which decking goes on top.

Modern Canadian pressure-treated lumber (post-2003) is treated with one of three copper-based preservatives: ACQ (alkaline copper quaternary), MCA (micronized copper azole), or CA-B (copper azole type B). These replaced the older CCA (chromated copper arsenate) which contained arsenic and was phased out for residential use in 2003. The current chemistry is much safer than CCA — but it's still chemicals: don't burn PT scraps, don't compost PT sawdust, wear gloves when cutting, and dispose of cut-offs in regular construction waste (not in compost or yard waste). The green tint on fresh PT comes from the copper.