Deck Cost Per Square Foot in Minnesota: What the Number Actually Includes

Decks in the Twin Cities cost $38 to $105 per square foot installed. Pressure-treated pine is $38–$58, cedar $52–$78, and composite $68–$105. A 16x20 (320 sq ft) composite deck therefore lands around $22,000–$34,000.

But per-square-foot pricing is the most misleading number in decking, and here is why.

Cost per square foot by material

Material	$/sq ft installed	320 sq ft deck	MN lifespan
Pressure-treated pine	$38–$58	$12,000–$18,500	12–18 yrs
Cedar	$52–$78	$16,500–$25,000	15–22 yrs
Composite (mid)	$68–$92	$22,000–$29,500	25–30 yrs
Composite (premium capped)	$80–$105	$25,500–$33,500	30+ yrs
PVC	$85–$115	$27,000–$37,000	30+ yrs
Hardwood (ipe)	$90–$130	$29,000–$41,500	30–40 yrs

Why small decks cost more per square foot

Fixed costs do not shrink with the deck. Permits, mobilization, footing excavation, ledger and flashing, stairs, and railing are largely the same on a 10x12 as on a 16x20.

Deck size	Typical $/sq ft (composite)
10' x 12' (120 sq ft)	$95–$135
12' x 16' (192 sq ft)	$80–$110
16' x 20' (320 sq ft)	$68–$92
20' x 24' (480 sq ft)	$62–$85

If you are on the fence about size, bigger is cheaper per square foot. Going from 12x16 to 16x20 adds 128 sq ft for roughly $9,000 — cheaper per foot than everything before it.

The six items that swing your bid

1. Height off the ground. A deck more than about 30" up requires guardrail, more substantial posts, and often stairs with landings. A ground-level deck is dramatically cheaper.
2. Stairs. $180–$450 per tread installed. A 6-step run with railing is $2,500–$5,500.
3. Railing. This is the sleeper cost. Pressure-treated wood railing is $30–$50/linear ft; composite is $60–$95; cable rail is $110–$220; glass is $180–$350. On a 320 sq ft deck with 60 feet of railing, that is a $4,000 to $20,000 line.
4. Footings. Minnesota requires footings below 42" frost. Helical piles on bad soil or tight access add $250–$600 each.
5. Ledger and flashing. Attaching to the house properly — bolts into the rim joist, flashing over the ledger. This is a life-safety item and the most common failure in DIY and cheap-contractor decks.
6. Extras. Built-in benches, lighting, skirting, a pergola, and under-deck drainage each add real money.

What a real bid should itemize

• Footing type, depth, and count
• Framing lumber and joist spacing (12" o.c. for composite diagonal runs)
• Decking product line and color
• Fastening method (hidden clips vs face screws)
• Railing system and linear footage
• Stair count and landing detail
• Ledger attachment and flashing method
• Permit and inspection

Any bid that gives you one number and a square footage is hiding where the money went.

Minnesota framing notes

• Joist spacing at 12" on center for composite installed diagonally; 16" for straight runs. Sagging composite is a spacing failure.
• Treated lumber must be rated for ground contact where framing is near grade.
• Use hot-dip galvanized or stainless fasteners — modern treated lumber corrodes cheaper hardware.
• Slope decking away from the house at about 1/8" per foot to shed meltwater.
• Leave gapping per manufacturer spec for thermal movement; our temperature swing is 130 degrees.

Frequently asked questions

How much does a deck cost per square foot in Minnesota? $38-$58 for pressure-treated pine, $52-$78 for cedar, and $68-$105 for composite, installed.

Is composite worth it in Minnesota? Over 20 years, usually yes. Composite costs more upfront but eliminates annual staining, which runs $600-$1,500 each time on a mid-size deck.

Do I need a permit for a deck? Yes in nearly every Twin Cities jurisdiction, especially for decks attached to the house or more than 30 inches above grade.

How deep do deck footings need to be? Below the 42-inch frost line in most of the metro. Deeper in some outer suburbs.

When should I build a deck in Minnesota? April through November. Frozen ground makes footings expensive; fall is often the best availability and pricing.

Send us your rough dimensions and we will give you a real itemized number, not a per-square-foot guess.