For most decks in BC's wet climate, composite costs more to build but usually less to own over the long run. It needs no staining and lasts about 25 to 30 years or more, while cedar typically lasts 12 to 20 years and needs oil or stain every 1 to 3 years. Cedar still makes sense if you want real wood, a lower build price and don't mind regular upkeep.
Upfront cost at a glance
Here is how the four common board materials compare in the Lower Mainland. Prices are typical installed figures for a new, low deck on a pressure-treated frame, before railings, stairs, permits and GST. They are for budgeting; real quotes depend on a site visit.
| Material | Installed cost per sq ft | Upkeep per year | Typical lifespan |
|---|---|---|---|
| Pressure-treated | $35 to $65 | $300 to $800 | 15 to 20 years |
| Cedar | $50 to $85 | $300 to $700 | 12 to 20 years |
| Composite | $60 to $100 | $0 to $200 | 25 to 30+ years |
| PVC | $75 to $120 | $0 to $150 | 30 to 50 years |
Cedar lumber prices are volatile, so cedar quotes can move with supply. Premium composite lines sit at the top of the composite range.
On a 300 sq ft deck, that works out to about $15,000 to $25,500 for cedar and $18,000 to $30,000 for composite. Try your own size in the deck cost calculator, or see our Lower Mainland deck cost guide for railings, stairs and permits.
10-year and 20-year cost on a 300 sq ft deck
The build price is only part of the story. This rough comparison uses typical local ranges for a 300 sq ft deck. It leaves out railings, stairs, inflation and GST, so treat it as a guide, not a quote.
| Rough estimate, 300 sq ft | Cedar | Composite |
|---|---|---|
| Build (300 sq ft x installed rate) | 300 x $50 to $85 = $15,000 to $25,500 | 300 x $60 to $100 = $18,000 to $30,000 |
| Upkeep per year | $300 to $700 | $0 to $200 |
| Upkeep over 10 years | $3,000 to $7,000 | $0 to $2,000 |
| 10-year total | $18,000 to $32,500 | $18,000 to $32,000 |
| Upkeep over 20 years | $6,000 to $14,000 | $0 to $4,000 |
| New boards by year 20 (300 x $20 to $50) | $6,000 to $15,000 | Not usually needed |
| 20-year total | $27,000 to $54,500 | $18,000 to $34,000 |
After 10 years, the two are roughly even, because staining uses up cedar's lower build price. By year 20, a cedar deck has usually needed new boards too, and composite pulls well ahead. If your cedar is well kept and lasts the full 20 years, remove the new-boards line. The gap narrows, but composite still tends to come out ahead.
Lifespan in a wet climate
Rain from fall to spring is hard on wood. Cedar typically lasts about 12 to 20 years here, and its life depends heavily on upkeep. Skip the staining and it shortens sharply on the coast.
Composite boards last about 25 to 30 years or more, and capped boards usually carry manufacturer warranties of 25 to 50 years. In short, the wet coastal climate favours composite, PVC and vinyl.
Moss, mildew and cleaning
Shaded, damp decks in the Lower Mainland are prone to moss and mildew, whatever they are made of. The difference is how much work it takes to keep on top of it.
Cedar is a soft wood that dents and checks, and it picks up mildew and algae in shaded, north-facing yards. Plan on a wash every year and fresh oil or stain every 1 to 3 years. Staining is only practical in dry weather, roughly May to September. A professional clean and stain of a 300 sq ft deck typically costs about $750 to $1,800.
Composite needs no staining or sealing, but it is not immune. Wash it once or twice a year with soap and a soft brush, and clean mould and mildew from shaded or damp spots before it builds up.
Heat and movement
Synthetic boards move with temperature, so builders leave expansion gaps between them. With PVC especially, check the gaps and fasteners from time to time.
If your deck faces south or west and gets strong afternoon sun, look at board samples outside on a warm day before you choose. Synthetic boards, especially darker colours, can feel warmer underfoot than wood.
Look and feel
Cedar is real wood, with the warm colour and grain many people want. Keeping that colour means a cedar-toned semi-transparent stain every 1 to 3 years, and the soft wood dents and checks over time.
Composite is made to look like wood, and the higher-end lines cost more. Look at full-size boards outdoors in daylight, and ask the builder to name the exact brand, line and colour in the quote.
Protect the frame: joist tape and flashing
Cedar and composite boards usually sit on a pressure-treated frame. On a composite deck that can last 25 years or more, frame rot, not the boards, is usually what limits the deck's life.
Two details matter most:
- Joist tape. A waterproof tape over the tops of the joists and beams. It adds about $1 to $2 per sq ft, or roughly $300 to $600 on a 300 sq ft deck.
- Ledger flashing. Proper flashing where the deck attaches to the house is critical in our climate.
Putting composite on an old frame? Composite often needs joists at 12 in (305 mm) on centre, so an older frame may need extra joists or blocking. Budget $500 to $2,500 for frame fixes.
Where pressure-treated and PVC fit
Pressure-treated wood is the budget choice at $35 to $65 per sq ft. It lasts about 15 to 20 years here, with a yearly wash and a fresh stain every 2 to 3 years, which runs about $300 to $800 a year. It suits tight budgets and simple, low decks.
PVC decking is the premium end at $75 to $120 per sq ft, usually 15 to 30% above mid-range composite. It is lighter, has no wood content for mould to feed on, needs only washing, and lasts about 30 to 50 years. Warranties typically run 25 to 50 years or lifetime, depending on brand and line.
If your deck sits over living space, none of these board options keeps the room below dry on its own. That needs a separate under-deck drainage system, at significant extra cost, or a waterproof vinyl membrane deck. Our vinyl deck guide explains how it works.
Which should you choose?
Choose cedar if you love real wood, want a lower build price and are happy to stain every year or two. It does best on sunnier decks, away from heavy shade.
Choose composite if your yard is shaded or damp, you plan to stay 10 years or more, or you would rather spend summer weekends on the deck than refinishing it. Whichever you pick, ask for joist tape and good ledger flashing. You can compare every option on our decking materials page.
The surest way to settle cedar vs composite for your yard is to price both. Get free quotes from up to three vetted local deck builders, ask each to quote cedar and composite side by side, and use our guide on comparing deck quotes to check them line by line.
Common questions
Does composite decking get mossy in BC?
It can. Composite does not need staining, but shaded or damp spots can still grow mould and mildew, so wash it once or twice a year with soap and a soft brush.
How often should you stain a cedar deck in the Lower Mainland?
Plan on oiling or staining cedar every 1 to 3 years in our wet climate, in dry weather between roughly May and September. A professional clean and stain of a 300 sq ft deck typically costs about $750 to $1,800.
Is composite decking worth the extra cost on the West Coast?
For most homeowners planning to stay 10 years or more, yes. In a rough 300 sq ft example, cedar and composite cost about the same after 10 years, and composite pulls ahead by year 20 because it needs no staining and lasts longer.
Can you put composite boards on an existing deck frame?
Sometimes, if the frame is sound. Composite often needs joists at 12 in (305 mm) on centre, so an older frame may need extra joists or blocking, which typically adds $500 to $2,500.