Every deck consultation we run in Oakville, Burlington, or Mississauga ends the same way. Homeowner says, "Just give me a number." We try to explain that decks don't have a single number — they have ten numbers stacked on top of each other, and the ten numbers are the whole point.
Because if any contractor is giving you a single number without walking you through the stack, they're either cutting a corner you can't see or padding a line you're not going to catch. This post is the stack. Written from real quotes we wrote last summer.
Ground rules. We're going to price a fairly typical GTA deck — 14 feet deep by 20 feet wide, attached to the house at the main-floor level, ranging 24 to 36 inches off grade (so a code-required railing), one short staircase off one corner, a flush-framed joist layout, no pergola, no built-in benches, no fancy electrical. The most common thing we actually quote.
Everything beyond that is a markup you can figure out from these numbers. We'll show the same deck in three materials: cedar, composite (Trex or TimberTech), and pressure-treated lumber. Same frame underneath, same deck size, same labor hours — just the decking and railing change. For the honest tradeoff on which material to pick, we wrote up cedar vs composite vs pressure-treated in detail separately.
The baseline deck: 14x20, attached, one staircase, one railing run
We lead with the frame because the frame is the part that will still be there in 25 years, and because the frame is where bad builders cut the hardest. Our standard spec for a 14x20 attached deck in the GTA is eight helical piles (Postech or Techno Metal Post) at 6 feet driven depth, a 2x10 pressure-treated ledger lag-bolted into the rim joist with Simpson SDWS through-bolts, 2x10 PT joists at 16" on centre hung in Simpson LUS hangers, 2x10 double-PT outer rim, and a 4x4 PT post-to-beam structure where the attached ledger can't carry a span. The footing decision is covered in our helical piles vs concrete footings writeup.
Fasteners matter more than homeowners think. We use 316 stainless steel hardware in every contact point with cedar or composite and hot-dip galvanized everywhere else, because the ACQ pressure-treated chemistry used in Ontario since 2004 will eat ordinary galvanized fasteners in about eight years.
The jump from HDG to 316 stainless adds maybe $220 to the material bill on a deck this size and buys you 25 years of worry-free fasteners. We don't quote the cheap version anymore. It's where most of the "why is this so expensive" conversations come from, and it's where we refuse to move.
- Footings: 8 helical piles at 6 ft, Postech — $5,600 to $8,000 CAD installed
- Ledger attachment: Simpson SDWS through-bolts at 16" OC, flashed with copper — $180 to $260 in hardware
- Frame: 2x10 PT joists, PT beams, 16" OC, Simpson LUS hangers at every joist — $2,400 to $3,200 in lumber
- Hardware: 316 stainless SS at contact points, HDG elsewhere — $620 to $820 total
- Permit + drawings: Oakville, Burlington, Mississauga municipal fees — $240 to $520
How much does a cedar deck cost in the GTA?
A cedar-top 14x20 deck on the frame described above runs $18,500 to $24,500 CAD installed in the GTA as of early 2026. The spread is mostly cedar grade — we price 2"x6" western red cedar (clear, kiln-dried, edge-grain where we can get it) from a proper lumberyard, not construction-grade cedar from a big box store. The difference between kiln-dried clear and green standard-grade cedar is about $2,800 on a deck this size, and the difference on your face when you look at it three years later is much bigger than that.
Cedar railings add another variable. Horizontal cable rail in aluminum posts with stainless cable is the cleanest look in cedar and runs about $140 to $200 per linear foot installed. Picket-and-top-rail cedar railing is cheaper ($75 to $110 per LF) but looks busier with cedar decking and fades unevenly. Most of our clients in Oakville go cable, most of our clients in Burlington go picket, and it's honestly a neighborhood style thing more than a price thing. Add $1,400 to $2,800 for the railing on a deck with a single 34-foot railing run.
- Cedar 2"x6" top (clear, kiln-dried, western red): $4,200 to $6,000 in lumber alone
- Hidden fasteners (Camo or DeckWise) for cedar: $400 to $550
- Cedar railing, cable system: $4,500 to $6,400 installed for a 34-foot run
- Cedar railing, picket system: $2,400 to $3,600 installed for a 34-foot run
- Stairs (single 36" wide run, 3 risers to grade): $900 to $1,400 in labor and material
- Finishing (Penofin or Sansin penetrating stain, two coats): $650 to $950
- Total cedar 14x20 deck installed: $18,500 to $24,500 CAD
How much does a composite deck cost in the GTA?
The same 14x20 deck topped in composite — Trex Enhance or TimberTech Pro, mid-tier — runs $22,800 to $29,500 CAD installed in 2026. Composite decking pricing moved twice last year and once more in January, so treat the low end of that range as optimistic if you're quoting in summer. High-tier composite (Trex Transcend, TimberTech Advanced PVC) adds another $1,800 to $3,200 to the material bill.
Composite joist spacing matters here. Most composites require joists at 12" on centre (not the standard 16"), which means we're framing a little heavier on composite jobs — an extra two to three joists for a 14-foot span. The frame cost goes up by about $180 to $260 in lumber and eighty bucks in hangers.
We include this in every composite quote up front; we've inherited cracked composite from jobs where the last crew laid TimberTech Advanced PVC on 16" framing and it sagged visibly by year three.
- Composite decking (Trex Enhance / TimberTech Pro, mid-tier): $5,800 to $8,400 in material
- Picture-frame border (contrasting color, recommended on composite): add $450 to $650
- Hidden fastener system (Trex or TimberTech proprietary clip): $480 to $680
- Extra joists for 12" OC composite framing: $260 to $340
- Composite railing (aluminum frame with composite top rail, LED post caps optional): $4,800 to $7,200 installed
- Total composite 14x20 deck installed: $22,800 to $29,500 CAD
How much does a pressure-treated deck cost in the GTA?
A pressure-treated 2x6 top on the same 14x20 frame runs $14,800 to $18,600 CAD installed. That's the number homeowners who walked into our first consultation with a $10,000 budget are looking for, and it's roughly where we can meet them without cutting the frame spec. We still use helical piles, we still use 316 stainless at every contact, and we still flash the ledger — we won't do PT on cheap footings.
The honest thing about a PT deck is that the top is a 10 to 15 year surface in the GTA, and the frame underneath is a 25 to 30 year frame. In practice, most of our PT clients do a "reskin" around year 12 — we pull the PT top, replace it with cedar or composite, reuse the frame, and it costs about 40% of a new deck.
We tell PT clients this at the first consultation because it changes how they think about the initial decision. A PT deck isn't cheap, it's phased.
- PT 2x6 decking (premium grade, kiln-dried after treatment): $1,800 to $2,600
- PT railing (2x2 balusters, 2x4 top rail, 4x4 posts — the cheap, fine look): $1,400 to $2,100 installed for 34-foot run
- Stainless deck screws (not hidden, face-screwed on PT): $220 to $320
- Stain (Ready Seal or Sikkens, two coats): $380 to $540
- Total pressure-treated 14x20 deck installed: $14,800 to $18,600 CAD
What pushes a deck quote up or down?
Three things change deck pricing more than the material: elevation, footprint shape, and the finish details. Elevation is the big one. A deck that's 24 inches off grade is one price. The same deck at 60 inches off grade (classic Oakville walkout over a basement) needs taller posts, a bigger beam, a longer stair run, and a fall-protection railing at code height — and it adds $3,500 to $6,500 to the job without any footprint change. If your house was built with a walkout, start the budget conversation at the composite high end, regardless of which material you pick.
Footprint shape moves the number less than you'd expect. A 14x20 rectangle and a 14x20 L-shape cost roughly the same in lumber; you save a little framing on the L because the spans are shorter, and you spend it back on more cuts and more waste. An octagonal deck corner, on the other hand, adds a full day of labor and about $600 in waste. We charge for it honestly because it's an honest addition of work.
Finish details are where homeowners quietly double the budget without noticing. Built-in bench wrapping a corner: add $1,800 to $2,800. Cedar pergola over the outdoor dining zone: $4,200 to $6,500 installed. Deck lighting package (LED riser lights, post caps, downlighting): $900 to $2,200 with an electrician. Underdeck rain ceiling system (Trex RainEscape or DryJoist) so a raised deck becomes a dry patio below: $2,800 to $4,500.
None of this is wrong — these are the details that turn a deck into a room — but they need to be priced line by line so a homeowner can make real choices. If you want to talk through it, our custom decks and patios service page is the place to start.
| Material | Low end (CAD) | High end (CAD) | Honest lifespan |
|---|---|---|---|
| Pressure-treated 2x6 | $14,800 | $18,600 | 10–15 years (top) |
| Western red cedar | $18,500 | $24,500 | 20–25 years |
| Mid-tier composite (Trex Enhance / TimberTech Pro) | $22,800 | $29,500 | 25+ years |
“The line-item sheet was the thing that sold me. Everybody else gave me a single number and a handshake.”
The reason we price decks this way — every line, every material, every hour — is that it's the only way a homeowner can make honest tradeoffs. If the budget comes in $3,200 over what you wanted, the line-item sheet tells you exactly where to take $3,200 out. Maybe it's dropping the cable railing for a picket. Maybe it's holding the cedar top and pushing the stain into year two. Maybe it's losing the built-in bench. Those are choices you can't make against a single bottom number, and they're the conversations we have in every second consultation call.
