In most GTA municipalities, a deck more than 24 inches off grade needs a permit, engineered guards, and inspected footings. This is genuinely good: the failures you read about are almost always unpermitted decks pulling away from houses at the ledger board. A proper contractor handles the drawings and the permit desk. If a quote's price depends on skipping the permit, you're being asked to hold someone else's risk.
Footings: why decks lean in this city
GTA frost reaches about 4 feet down, so footings must too. Deck blocks sitting on grade ride the frost like a boat: up in January, down (unevenly) in April. That's the wavy, drunk-uncle deck you've seen. Sonotubes to below frost line, sized to the load, are non-negotiable for anything attached to a house. For low floating decks, helical piles have become the smart-money option: installed in a day, no concrete cure, removable.
Pressure-treated vs composite, the 10-year math
PT lumber costs roughly half up front and wants staining every 2–3 years; skip it and boards check, cup, and grey. Composite costs more on day one, then asks for soap and water, ever. Over ten years, an honestly maintained PT deck plus stain weekends often lands within shouting distance of composite money. Buy PT if you'll actually maintain it or love the wood look; buy composite if your weekends are worth more than the delta.
The parts that fail first
Ledger connection (where deck meets house): needs proper flashing and structural fasteners, not deck screws; this is the failure that drops decks. Guardrails: should take a hard shove without a wiggle; more than a quarter inch of movement is a fix-now item. Stair stringers: rot at the bottom cut where they meet concrete. Joist tops: water sits under boards; joist tape at build time adds years for pennies. We look at all four before quoting anything.
Your once-a-season walk-around
Tick what checks out. Anything you can’t tick is worth a closer look.
Things people get told (that aren’t quite true)
“Composite is maintenance-free and rot-proof”
The boards are; the wood structure underneath usually isn't. Composite decking on rotting PT joists is lipstick on a liability. Deck health is measured under the deck.
“Deck blocks are fine for small decks”
For a low floating platform, sometimes. For anything attached to your house or holding a hot tub crowd, frost-depth footings or piles. Blocks and frost are a bad marriage in Ontario.
“Staining is cosmetic”
Stain is UV and water armour for the lignin in the wood. Grey isn't a colour choice; it's the surface fibres dying. Two hours with a roller every couple of summers doubles a PT deck's good years.
Deck check: build, fix, or relax?
1. The screwdriver test says…
2. The guardrail…
3. Age and history?
Questions we hear every week
What does a new deck cost in the GTA?
Pressure-treated builds run roughly $35–$60 per square foot in 2026 — $8,000–$25,000 for most projects. Composite adds material cost but ends staining forever.
Do I need a permit?
Usually yes above 24 inches off grade in most GTA municipalities. A good contractor handles the drawings and application.
How do I check my old deck?
Poke joists with a screwdriver each spring — soft means rot. A railing that moves more than a quarter inch is a fix-now item.
When should I book?
Deck season books out by May — reserve a spring date in winter for the best pricing.
How to Build an Outdoor Enclosure | lfbuilders
Outdoor enclosures are structures designed to enclose an outdoor space, such as a garden or patio. They can be made from various materials, including wood, metal, plastic, or glass, and come in a wide range of sizes, shapes, and styles. This is a companion dis
Outdoor enclosures are structures designed to enclose an outdoor space, such as a garden or patio. They can be made from various materials, including wood, metal, plastic, or glass, and come in a wide range of sizes, shapes, and styles. This is a companion dis…
