Deck Foundation Cost Calculator

Estimate how many footings your deck needs, then compare what each foundation method costs — floating deck blocks, DIY concrete tube footings, DIY screw piles, and pro-installed helical piles. Not sure which to use? The deck foundations & frost guide resolves the choice by soil and attachment first.

Your Deck

Deck length (ft)

The side running along the house.

Deck depth (ft)

How far it projects from the house.

Attachment

Attached decks must bear below the frost line.

Soil

Holds an augered hole — tube footings work well.

Frost region

Sets footing depth. Confirm with your municipality.

Frost depth override (ft)

Leave blank to use the region default.

Adjust layout assumptions & unit prices (CAD, editable)

Max post spacing along beam (ft)

Max joist span / beam spacing (ft)

Override footing count

Blank = auto-estimate from size.

Tube diameter (in)

Deck block ($ each)

Concrete tube ($/ft)

Concrete, 30 kg bag ($)

Each bag yields ~0.0135 m³.

DIY screw pile ($ each)

Pro-installed helical pile ($ each)

Auger rental ($/day)

Mixer rental ($/day)

Include auger + mixer rental in Sonotube cost

Recommended for your deck

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Method Comparison

Method	What's included	Est. cost

Plan the rest of the deck: read the deck foundations & frost guide for which method your soil and attachment call for, price the framing in the Wall Framing Calculator, and check the permits guide before you dig.

Disclaimer: This is a planning-level estimate using simplified layout assumptions, not a structural design. The number, size, and depth of footings are governed by your deck loads, soil, provincial code, and permit drawings. Floating deck blocks are only for low, freestanding decks where your municipality permits a non-frost-protected foundation. Always confirm required footing depth and permit requirements with your municipality, and consult an engineer for tall, heavy, or complex decks.

How this estimate works

Footing count is estimated as a grid: posts per beam line = ⌊length ÷ post spacing⌋ + 1, multiplied by the number of beam lines = ⌈depth ÷ joist span⌉ (plus one extra line for a freestanding deck, which needs a beam on both edges). You can override the count. Concrete tube footings: each hole goes to the frost depth plus a 6″ margin; concrete volume = π × (tube radius)² × depth, converted to 30 kg bags (~0.0135 m³ each), plus the tube by the foot, plus a one-time auger + mixer rental if enabled. Deck blocks, DIY screw piles, and pro-installed helical piles are simply the footing count × your editable unit price. Costs are shown ±15%.