16x20 Deck Cost in Ontario 2026: $14,400 to $30,400 (Real Quotes)
A 16x20 deck (320 sqft) costs $14,400-$30,400 installed in Ontario. PT, cedar & composite pricing with permits, footings, railing — based on real 2026 project data.
A 16x20 deck gives you 320 square feet of outdoor living space—enough for a dining set, lounge chairs, and a BBQ station. In Ontario's 2026 market, expect to pay $14,400 to $30,400 installed, depending on your material choice and site conditions.
Here's what drives the cost and how to budget for your project. You can also check our Ontario deck cost per square foot breakdown for general pricing benchmarks. Our complete Ontario deck cost guide covers all sizes and material options.
16x20 Deck Cost Breakdown by Material
Your decking material is the biggest cost factor. Here's what 320 square feet will run you in the Kitchener-Waterloo-Cambridge area:
Pressure-Treated Deck
Total installed cost: $14,400 - $20,800
- Material: $45-65/sqft installed
- Framing lumber: Included in per-sqft price
- Standard railing: $40-70/linear foot
- Permit: $150-400
Pressure-treated pine is the most affordable option. Expect to stain or seal it every 2-3 years. In Ontario's freeze-thaw climate, proper maintenance prevents warping and splitting. Learn the maintenance schedule.
Composite Deck
Total installed cost: $20,800 - $30,400
- Material: $65-95/sqft installed
- Hidden fasteners: Usually included at this price point
- Composite railing: $70-120/linear foot
- Permit: $150-400
Composite needs virtually no maintenance and won't rot, splinter, or fade like wood. Trex, TimberTech, and Fiberon are popular in Ontario. Compare composite costs in Waterloo.
Cedar Deck
Total installed cost: $17,600 - $25,600
- Material: $55-80/sqft installed
- Natural oils provide rot resistance
- Cedar railing: $50-90/linear foot
- Permit: $150-400
Cedar looks beautiful and resists rot naturally, but you'll still need to seal it annually to maintain colour. See how cedar compares to composite.
What's Included in the Installed Price?
When builders quote $45-95/sqft "installed," here's what that typically covers:
Foundation:
- Excavation and footing holes
- Concrete footings or helical piles (48" deep minimum per OBC)
- 6x6 posts set in place
Framing:
- Ledger board attached to house with proper flashing
- Rim joists and blocking
- 2x8, 2x10, or 2x12 joists depending on span
- Joist tape or membrane on top of framing
Decking:
- Deck boards installed with proper spacing
- Fascia board trim
- Hidden fasteners (composite) or deck screws (wood)
Railing:
- Posts, top/bottom rails, balusters
- Meets Ontario Building Code height requirements (42" minimum for decks over 24")
Not usually included:
- Stairs (typically $800-2,500 extra depending on height and material)
- Built-in benches or planters
- Deck lighting
- Pergola or shade structure
Always get a written quote with line items. Use this checklist when reviewing quotes.
Additional Costs to Budget For
Permit Fees
$150-400 depending on your municipality. Kitchener, Waterloo, and Cambridge each have their own fee structures. Your deck will need a permit if it's over 24" high or attached to your house. See Kitchener's permit rules.
Footings and Site Conditions
Standard pricing assumes normal soil and straightforward access. You'll pay more if you have:
- Clay soil: Harder to dig, may require equipment ($300-800 extra)
- Sloped yard: Extra excavation and taller posts ($1,200-3,500)
- Tight access: No room for equipment means hand digging ($500-1,500)
- High water table: May need drainage work ($800-2,000)
Helical piles cost $150-300 each but can save money on sites with difficult digging or high water tables. They're installed in 30 minutes per pile versus 2-3 hours per concrete footing.
Stairs
A single set of stairs (3-5 steps) adds $800-2,500 depending on width and material. Composite stairs cost more but match your deck and won't rot where they contact the ground.
Demolition
Removing an old deck runs $500-2,000 depending on size and disposal fees. Some builders include this in their quote; others charge separately. Get the full breakdown on demo costs.
How Many Footings Does a 16x20 Deck Need?
Typically 8-12 footings, depending on your joist span and framing design.
Standard layout:
- 4 footings along the house (ledger side)
- 4 footings at the outer beam (16' away)
- 0-4 intermediate footings if using 2x8 joists over longer spans
Each footing must go 48 inches deep (1.2 m) to sit below Ontario's frost line. Frost heave will lift shallow footings and crack your deck frame. Read the full frost line guide.
Your builder will check joist span tables to determine spacing. See Ontario span requirements for 2x8, 2x10, and 2x12 joists.
16x20 Deck Railing Cost
Perimeter railing adds $1,600-4,800 depending on material and design.
A 16x20 deck typically needs 40-48 linear feet of railing (depends on stairs and which sides are open).
Railing cost per linear foot:
- Pressure-treated wood: $40-70
- Cedar: $50-90
- Composite: $70-95
- Aluminum or vinyl: $80-120
- Cable or glass: $100-150
Compare railing options and code requirements.
Is a 16x20 Deck Big Enough?
320 square feet works well for:
- 6-8 person dining table
- Two lounge chairs or a loveseat
- BBQ station with prep space
- Small planter or side table
It's a popular size for typical KWC backyards (40-60 feet deep). You'll have room for entertaining without overwhelming your yard.
Too small? Consider 12x24 (288 sqft) if you have a narrow lot, or go larger to 20x20 (400 sqft) if you want separate dining and lounging zones.
When to Build Your Deck
Best time: May through October when the ground is workable and weather is predictable.
Spring (April-May): Builders are busy but weather can be unpredictable. Book in February for May start dates.
Summer (June-August): Peak season. Expect 6-10 week lead times and less flexibility on pricing.
Fall (September-October): Shoulder season with good availability. Ground is still diggable and weather is stable.
Winter: Most builders won't dig footings when the ground is frozen, but you can get better pricing if you book for spring installation. See the full seasonal breakdown.
How to Get Accurate Quotes
Follow these steps to compare builders and avoid surprises:
1. Measure your space. Know the deck size you want before requesting quotes. Use this measuring guide.
2. Request at least 3 quotes. Get written estimates that break down materials, labour, and extras. Use this email template.
3. Ask about site conditions. Will they charge extra for clay soil, slopes, or difficult access? Get it in writing.
4. Check what's included. Does the quote include stairs, railing, permit application, and cleanup? Review this quote checklist.
5. Understand the timeline. How long from deposit to completion? When do you pay? See typical quote-to-contract timelines.
6. Get a contract. Never start without a signed contract that specifies materials, timeline, payment schedule, and warranty. What to include in your deck contract.
DIY vs. Hiring a Builder
DIY material cost for 16x20 deck:
- Pressure-treated: $5,000-8,000
- Composite: $9,000-14,000
- Cedar: $7,000-11,000
You'll save $7,000-16,000 in labour, but you'll need:
- 200-300 hours of work
- Tools: circular saw, drill, level, post-hole digger or auger rental ($80/day)
- Knowledge of OBC framing requirements
- Permit drawings (or pay someone to draw them: $300-600)
- Someone to help lift beams and joists
DIY makes sense if:
- You have construction experience
- You can dedicate 3-4 weekends (or 2-3 full weeks)
- You're comfortable with permit drawings and inspections
- You have a helper
Hire a builder if:
- You want warranty coverage (most pros offer 1-5 years)
- Your site has slopes, clay soil, or tight access
- You need the job done in 1-2 weeks instead of months
- You want insurance protection during construction
Deck Permit Process in KWC
Every municipality handles permits differently:
Kitchener: Apply online through the city portal. Expect 2-3 weeks for approval. Step-by-step Kitchener permit guide.
Waterloo: Online or in-person submission. 2-4 week turnaround. Waterloo permit walkthrough.
Cambridge: Paper or online applications accepted. 3-4 weeks typical. Cambridge permit process.
You'll need:
- Site plan showing deck location and setbacks
- Framing plan with joist sizes and spacing
- Footing depth and spacing details
- Railing elevation if over 24"
Check the full permit drawing checklist.
Cost-Saving Tips
Choose standard sizing. Deck boards come in 12', 16', and 20' lengths. Design your deck to minimize waste—a 16x20 deck uses full-length boards efficiently.
Go with pressure-treated wood. You'll save $6,000-10,000 versus composite and still get 15-20 years of life with proper maintenance.
Skip the extras. Built-in benches, planters, and lighting are nice but add $2,000-5,000. You can always add them later.
DIY the finishing. Have a pro install the structure but do the staining or sealing yourself. Save $800-1,500.
Build in the off-season. Book for fall installation when builders have more availability and may offer better rates.
Red Flags When Comparing Quotes
Watch out for builders who:
- Quote well below market rates (often means corners will be cut)
- Won't provide written estimates with line items
- Don't mention permits or say "you don't need one"
- Ask for full payment upfront
- Can't provide references or photos of previous work
- Use 2x6 joists for spans over 8 feet (undersized, won't pass inspection)
- Don't include ledger flashing in the quote (leads to rot and water damage)
A quality deck should last 15-25 years depending on material and maintenance. Don't sacrifice structural integrity to save $2,000. Avoid these common design mistakes.
Common Questions
What's the difference between an estimate and a quote?
An estimate is an approximate price range based on general information. A quote is a firm price based on a site visit and specific materials. Get quotes in writing before signing anything. Read the full breakdown of estimates vs quotes vs contracts.
How long does it take to build a 16x20 deck?
5-10 business days for a professional crew. DIY projects typically take 3-6 weekends depending on experience and weather. Factor in 2-4 weeks for permit approval before construction starts. See typical timelines from quote to completion.
Do I need a permit for a 16x20 deck in Ontario?
Yes, almost certainly. Any deck over 24" high or attached to your house requires a permit in Kitchener, Waterloo, and Cambridge. Even low decks need permits if they're attached to the building. Permit fees are $150-400. Check Kitchener's 24-inch rule or see Waterloo's requirements.
Should I use concrete footings or helical piles?
Concrete footings are standard and work well in most situations ($100-150 per footing). Helical piles cost more ($150-300 each) but install faster, work better in clay soil or high water tables, and don't require concrete curing time. Your builder can recommend the best option for your site. Compare helical piles vs concrete footings.
Can I build a deck right up to my property line?
No. Kitchener, Waterloo, and Cambridge all require setbacks from property lines—typically 2-4 feet depending on zoning. Check your municipality's setback rules before finalizing your deck size. Learn how to check setbacks for your property.
Related guides (to compare apples-to-apples quotes)
Local deck pages (Kitchener-Waterloo-Cambridge):
Cost + sizing comparisons:
Materials + structure:
Get quotes: /#quote-form
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