Planning a new deck in Toronto or the GTA almost always starts with the same question: what is this going to cost? The honest answer is that "a deck" can mean a $6,000 pressure-treated platform off the back door or a $26,000 composite entertaining space with glass railings and a staircase. Size is the single biggest driver, but it is not the only one. At Deck Master Inc., we have been building decks across Toronto and the GTA since 2004, and this guide lays out realistic 2027 installed price ranges for the four most common sizes — in both pressure-treated wood and composite — plus the factors that move your number up or down.
How deck pricing works in the GTA
Deck builders here generally price on a per-square-foot basis, then adjust for the details of your yard and design. As a rough 2027 benchmark across the GTA, a pressure-treated deck runs about $30 to $45 per square foot installed, while a composite deck runs about $45 to $78 per square foot installed. Those are turnkey numbers — material and labour together, built by an insured crew — not just the cost of lumber.
Where a specific project lands inside those ranges depends on height, stairs, railing style, footings, demolition, access and permits. We will break each of those down below, but the fastest way to get a ballpark for your own layout is our deck cost calculator, which lets you plug in size and materials before you ever book a site visit. You can also see finished local projects in our project gallery.
Deck cost by size in Toronto (2027)
The table below shows typical installed total-cost ranges for a standard single-level deck at a reasonable height, with a basic railing and one set of steps. Upgrades like glass railings, multiple levels or a raised second-storey deck push you toward and past the top of each range.
| Deck size (sq ft) | Pressure-treated (installed) | Composite (installed) |
|---|---|---|
| 12 × 12 (144 sq ft) | $5,800 – $6,500 | $8,400 – $11,200 |
| 12 × 16 (192 sq ft) | $6,900 – $8,400 | $10,400 – $14,200 |
| 16 × 20 (320 sq ft) | $10,200 – $13,400 | $15,400 – $22,400 |
| 20 × 20 (400 sq ft) | $12,000 – $16,000 | $18,000 – $26,400 |
What a 12×12 or 12×16 deck gets you
A 12×12 (144 sq ft) deck comfortably fits a table for four or a lounge seating set, and it is the most common request we get from Toronto townhomes and smaller backyards. A 12×16 (192 sq ft) adds enough room to separate a dining zone from a barbecue area. Because fixed costs such as mobilization, footings and permits are spread over fewer square feet, these smaller decks carry the highest per-square-foot pricing — more on that below.
What a 16×20 or 20×20 deck gets you
A 16×20 (320 sq ft) or 20×20 (400 sq ft) deck is true outdoor-living territory: dining, lounging and a grill station without anything feeling cramped. Per square foot these are your best value, but the larger footprint means more framing, more railing and often an engineered design, so the total dollar figure is the highest. For a side-by-side material comparison on a larger build, our guide on composite decking walks through the long-term trade-offs.
What the base price includes, and what adds cost
Every quote should be clear about what is in the number and what is extra. Here is how a standard Deck Master build breaks down against the common add-ons we see in the GTA.
| Included in the base build | What adds to the price |
|---|---|
| Pressure-treated frame on concrete footings | Deck height over 2 ft or multiple levels |
| Decking boards (pressure-treated or composite) | Stairs, landings and extra sets of steps |
| Basic pressure-treated or aluminum railing | Glass, cable or premium aluminum railing |
| Hidden fasteners on composite builds | Removal and disposal of an old deck |
| Job-site cleanup and haul-away | Building permit and engineered drawings |
| Standard backyard access | Tight access, laneway lots or crane work |
Railings: glass versus aluminum
Railing is one of the biggest swing factors. Aluminum picket railing is durable, low-maintenance and the most budget-friendly upgrade. Tempered-glass railing delivers an unobstructed view and a premium look, but it can add several thousand dollars to a mid-sized deck. On a 16×20 build, choosing glass over standard aluminum is often the difference between the middle and the top of the composite range above.
Height, stairs and footings
A ground-level deck needs less structure than a raised deck off a second-storey walkout. The higher the deck, the more footings, posts and bracing are required, and the more likely you are to need engineered drawings and a longer staircase. Toronto's frost line also means footings must go deep enough to resist heaving over our freeze-thaw winters — a detail that protects the deck for decades but adds to the base cost.
Demolition, permits and site access
If we are replacing an existing deck, demolition and disposal are a separate line item. Permits are required for most decks in Toronto and surrounding municipalities, and the application and drawings add both cost and lead time. Finally, access matters: a wide-open yard is quick to work in, while a narrow side passage or a laneway lot slows material handling and labour.
Why small decks cost more per square foot
It surprises a lot of homeowners, but a 12×12 deck costs more per square foot than a 20×20. The reason is fixed costs. Mobilizing a crew, digging and pouring footings, pulling a permit and setting up the site cost roughly the same whether the deck is small or large. On a 144 sq ft deck those fixed costs are spread over very little area, so the per-square-foot figure climbs. On a 400 sq ft deck the same fixed costs are diluted across more than twice the area. If you are on the fence about size, building slightly bigger often adds less than you would expect per extra square foot.
Pressure-treated or composite?
Pressure-treated wood has the lowest upfront cost and a classic look, but it needs cleaning, staining and occasional board replacement over its life. Composite costs more to install but is low-maintenance and typically carries a long manufacturer warranty — brands like Trex and TimberTech back their boards for decades against rot, fading and staining. Over 15 to 20 years, the maintenance savings often close much of the gap. We install both, and you can read more about our approach on our deck building services page.
Frequently asked questions
How much does a deck cost in Toronto in 2027?
For a standard single-level deck, expect roughly $30 to $45 per square foot installed for pressure-treated wood and $45 to $78 per square foot for composite. A typical 12×16 runs about $6,900 to $14,200 depending on material and finishes, while a larger 20×20 runs from about $12,000 up to $26,400. Our detailed Toronto deck cost guide has more context on how these numbers are built.
Do I need a permit for my deck?
Most decks in Toronto and the GTA require a building permit, especially those attached to the house or raised above grade. Requirements vary by municipality and deck height, so we confirm the rules for your address and, when permits are needed, handle the drawings and application as part of the project.
How long does a deck take to build?
A straightforward single-level deck is usually built in a few days once materials are on site. Larger or raised decks, glass railings and permit timelines extend the schedule. We give you a realistic timeline with your quote so there are no surprises.
Why should I choose Deck Master?
We have built decks across Toronto and the GTA since 2004, we are WSIB-insured, and we are a Home Depot Pro partner with access to quality materials at fair pricing. We were also named a HomeStars "Best of" winner in 2022, 2024 and 2025 — recognition that comes from how our projects hold up and how we treat homeowners through the process.
Ready to turn a size into a real number for your yard? Start with our cost calculator for a quick estimate, then contact Deck Master for a free, no-obligation quote tailored to your space, your material choice and your budget.