The $/sq ft range, and what it actually includes
Per-square-foot pricing is a blunt instrument but a useful starting point. The range we quote, $700 to $1,200 per square foot, covers a four-season cottage with custom finishes, on a road-access lot, with no extreme site work.
Lower end: standard road access, simple foundation, dimensional lumber framing, mid-grade finishes, typical mechanical. Upper end: difficult site access, helical pile or ICF foundation, timber framing, premium finishes (clear cedar, smart glass, hand-built cabinetry), heavy mechanical (geothermal, full off-grid backup).
What's included in that range: construction trades, materials, project management fee, permits, and a reasonable contingency. What's not: lot purchase, design fees, furnishings, landscaping beyond shoreline naturalization, and any extreme site work like blasting or marine engineering.
Line-item breakdown for a 4,000 sq ft build
Foundation and site: 8–14% of hard cost. ICF, helical piles, or poured concrete on bedrock.
Framing and envelope: 18–24%. Timber, dimensional lumber, sheathing, insulation, vapour barrier, siding.
Mechanical (HVAC, plumbing, electrical, well, septic): 18–22%. Heaviest on year-round builds with redundant systems.
Roof and exterior finishes: 10–14%. Standing-seam metal, cedar shake, decks.
Interior finishes (millwork, flooring, tile, cabinetry, paint): 22–28%. The owner-controlled variable.
Windows and glazing: 8–12%. Triple-pane is standard now on year-round builds.
Construction management fee or builder margin: 7–18%, depending on model. See our CM vs GC guide.
What moves the budget more than finishes
Lot access. Winter-only access, water-only access, or a long unmaintained road can add 5–15% to the build cost.
Site preparation. Bedrock outcrops requiring blasting, soft soil requiring helical piles, or significant grade change all show up in the foundation line.
Approvals. Conservation-authority lakes and complex permitting add 3–6 months and meaningful cost in pre-construction.
Build season compression. If you must move into the cottage by a fixed date, the trade schedule has to overlap; overlap costs money.
Choice of construction model. A 15% GC markup vs a 7% CM fee on a $1.7M trade scope is $136,000.
Questions to ask before you sign
How is your fee structured? Is there any markup on trades or materials?
Will you show me every quote and every invoice?
What's your weekly reporting cadence?
Who will be on my site every day, and will I have their cellphone?
What happens if the project runs over the budget you've quoted?