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Instant fence & deck estimate
01 / 09What a deck costs to build in the GTA — pressure-treated, cedar and composite priced per square foot, including footings, permits and railing.
Three things set the price of a deck, and they multiply rather than add. Footprint is the obvious one. Height off the ground is the one people underestimate, because past a certain height the deck needs guards, and the framing, footings and stair runs all grow with it. A raised deck costs considerably more per square foot than a ground-level platform of the same area. Material sets the last band, from pressure-treated framing and decking through cedar to composite and PVC surfaces.
Stairs deserve their own mention. A stair run is the most labour-dense part of a deck per square foot of finished surface, and a taller deck needs a longer run, sometimes with a landing.
A deck board calculator estimates material for a rectangle on flat ground. It cannot price the conditions that decide the real number:
Use a calculator to sanity check a quote, not to replace one. We measure the yard, confirm what your municipality requires for the deck you want, and issue a fixed written price that covers the structure and the finish together.
Three drivers set the price and they multiply, which is why two decks of the same area can be very different jobs.
| Driver | What it covers | Why it moves the number |
|---|---|---|
| Footprint | Finished area of the deck | The obvious one, and the one people quote first |
| Height off the ground | Guards, framing, footings and stair runs | Past a certain height guards become mandatory and everything below grows, so a raised deck costs considerably more per square foot than a ground-level platform of the same area |
| Material | Pressure-treated framing and decking through cedar to composite and PVC | Sets the last band |
| Stairs | The stair run, and a landing on taller decks | The most labour-dense part of a deck per square foot of finished surface |
| Railing | Guard system along the perimeter and stairs | Effectively its own budget line, especially in aluminum or glass |
Footings below the frost line and site access sit underneath all of it, and neither shows up on a calculator.
Four hundred square feet is a large deck and the cost spread on it is wide. Height drives it hardest: at ground level you need no guards and short or no stairs, while a deck raised to a second-storey door needs taller posts, more footings, a full guard system and a longer stair run, which can approach a significant share of the build on its own. Material for the walking surface sets the next band, from pressure-treated through cedar to composite and PVC. Railing choice — wood, aluminum, glass — moves the total more than most people expect at this size.
Then footings below the frost line in clay, access for materials, and any grade change. A deck this size will usually require a permit. We quote a fixed written price after measuring and confirming what the municipality needs.
A twelve by twelve is the most common size we are asked about and it is a good value footprint, because the frame is simple and a single beam line often does the job. Cost depends on whether it sits at grade or is raised. At grade with no guards required and one or two steps down to the lawn, you are paying mostly for footings, frame and surface. Raised high enough to need guards, the same footprint costs noticeably more, because the guard runs the full perimeter and the stairs get longer.
Material choice is the other lever — pressure-treated surface at the accessible end, cedar above it, composite and PVC above that. Footings still have to reach below the frost line regardless of size. We measure the intended location, check the permit threshold, and issue a fixed written price.
A poured concrete patio at grade is usually cheaper than a deck of the same area, because there is no framing, no footings below the frost line, no guards and no stairs. It is also very low maintenance. But it only competes on cost where the ground is already close to level and near the door height. As soon as you need to bridge a drop — a walkout that sits well above grade, or a sloping yard — concrete needs retaining and fill, and a deck becomes both cheaper and better.
A deck also lets water and air through, works over utilities and tree roots, can be built to meet a door threshold exactly, and can be modified later. Concrete cracks in this freeze-thaw climate and is difficult to alter. The honest deciding factor is the height difference between your door and your grade.
On most decks it is the structure you never see plus the railing you do. Footings and framing take the largest labour share, because every footing has to be dug below the frost line, poured and set before any deck board is laid, and in GTA clay that is real work. If the deck is raised, the guard system becomes the other big number — it runs the entire perimeter, and aluminum or glass costs considerably more per foot than a wood picket guard.
Stairs are expensive per square foot too, since a run needs its own footing, stringers and a handrail. The walking surface material matters, but it is a smaller share of the total than people assume, which is why upgrading the surface is often better value than it looks. We itemise these so you can see where the money goes.
At around two hundred and eighty square feet this is a full outdoor living space, and in Canada the regional factor that matters is frost depth. Footings here have to bear below a frost line that is deep in southern Ontario, so the foundation work behind a deck this size is more substantial than it would be in a milder climate. Beyond that, the same drivers apply everywhere: height off grade and therefore guards and stairs, the walking surface material, the railing system, and access to the site. A deck of this size will normally require a building permit in GTA municipalities, and the drawings and review are part of the timeline. Rather than quote a national figure, we size the framing to code for your actual deck and issue a fixed written price.
Four hundred square feet is a large deck and the cost spread on it is wide. Height drives it hardest: at ground level you need no guards and short or no stairs, while a deck raised to a second-storey door needs taller posts, more footings, a full guard system and a longer stair run, which can approach a significant share of the build on its own. Material for the walking surface sets the next band, from pressure-treated through cedar to composite and PVC. Railing choice — wood, aluminum, glass — moves the total more than most people expect at this size. Then footings below the frost line in clay, access for materials, and any grade change. A deck this size will usually require a permit. We quote a fixed written price after measuring and confirming what the municipality needs.
A twelve by twelve is the most common size we are asked about and it is a good value footprint, because the frame is simple and a single beam line often does the job. Cost depends on whether it sits at grade or is raised. At grade with no guards required and one or two steps down to the lawn, you are paying mostly for footings, frame and surface. Raised high enough to need guards, the same footprint costs noticeably more, because the guard runs the full perimeter and the stairs get longer. Material choice is the other lever — pressure-treated surface at the accessible end, cedar above it, composite and PVC above that. Footings still have to reach below the frost line regardless of size. We measure the intended location, check the permit threshold, and issue a fixed written price.
A poured concrete patio at grade is usually cheaper than a deck of the same area, because there is no framing, no footings below the frost line, no guards and no stairs. It is also very low maintenance. But it only competes on cost where the ground is already close to level and near the door height. As soon as you need to bridge a drop — a walkout that sits well above grade, or a sloping yard — concrete needs retaining and fill, and a deck becomes both cheaper and better. A deck also lets water and air through, works over utilities and tree roots, can be built to meet a door threshold exactly, and can be modified later. Concrete cracks in this freeze-thaw climate and is difficult to alter. The honest deciding factor is the height difference between your door and your grade.
On most decks it is the structure you never see plus the railing you do. Footings and framing take the largest labour share, because every footing has to be dug below the frost line, poured and set before any deck board is laid, and in GTA clay that is real work. If the deck is raised, the guard system becomes the other big number — it runs the entire perimeter, and aluminum or glass costs considerably more per foot than a wood picket guard. Stairs are expensive per square foot too, since a run needs its own footing, stringers and a handrail. The walking surface material matters, but it is a smaller share of the total than people assume, which is why upgrading the surface is often better value than it looks. We itemise these so you can see where the money goes.
At around two hundred and eighty square feet this is a full outdoor living space, and in Canada the regional factor that matters is frost depth. Footings here have to bear below a frost line that is deep in southern Ontario, so the foundation work behind a deck this size is more substantial than it would be in a milder climate. Beyond that, the same drivers apply everywhere: height off grade and therefore guards and stairs, the walking surface material, the railing system, and access to the site. A deck of this size will normally require a building permit in GTA municipalities, and the drawings and review are part of the timeline. Rather than quote a national figure, we size the framing to code for your actual deck and issue a fixed written price.
