How Big is a 16×20 Deck?

320
square feet
·
16×20
dimensions (ft)
·
Deck
category

What Does 16×20 Actually Look Like?

This deck equals the floor area of a large family room or small apartment. Picture the size of a two-car garage or visualize it as roughly equivalent to four standard parking spaces arranged in a rectangle.

A 16×20 deck covers the same ground area as a large RV or small mobile home footprint.

A 16×20 deck delivers 320 square feet of premium outdoor living space, representing the gold standard for family entertainment areas. This generous size accommodates multiple activity zones simultaneously—dining, lounging, and grilling areas can coexist without crowding. The proportions work exceptionally well for larger homes and provide the scale needed for substantial outdoor furniture arrangements.

The 16-foot width allows for comfortable traffic flow around furniture, while the 20-foot length creates distinct spaces for different activities. This size deck can handle large family gatherings, outdoor parties, and everyday relaxation with equal ease. The substantial footprint requires careful structural planning but rewards homeowners with a true outdoor room that significantly extends living space.

What Fits in 16×20?

  • Large dining table seating 8-10 people
  • Full outdoor sectional sofa
  • Large gas grill with prep station
  • Fire pit with surrounding chairs
  • Outdoor kitchen island
  • Multiple lounge chairs
  • Large umbrella or pergola
  • Outdoor bar cart
  • Substantial planter arrangements

16×20 Deck Structural Specs

4
Beams
15
Footings
48
Deck Boards
16 inches on center
Joist Spacing

Material Comparison

Material $/sq ft Pros Cons
Pressure-treated lumber $12 Cost-effective for large projects, structural reliability, wide availability Significant maintenance requirements, weathering and warping over time
Composite decking $22 Minimal maintenance, consistent appearance, long-term durability High initial investment, heat retention, expansion and contraction issues
Tropical hardwood $18 Premium appearance, extreme durability, natural weather resistance Expensive, requires specialized installation, limited local availability

16×20 Deck Materials List

Material Quantity Est. Cost
Pressure-treated decking boards (5/4" x 6") 48 pieces 720
Pressure-treated joists (2" x 10" x 16') 18 pieces 450
Pressure-treated beams (2" x 10") 6 pieces 180
Concrete deck footings 15 pieces 225
Galvanized joist hangers 36 pieces 55
Deck screws (2.5") 15 lbs 120
Galvanized carriage bolts 30 pieces 50
Composite railing system 72 linear feet 1080

How Much Does a 16×20 Deck Cost?

Expect to pay between $4,800 and $12,800 to build. Material choice is the biggest cost driver. Composite costs 2-3x more than pressure-treated.

Common Uses for 16×20

Large family gatherings and parties Outdoor dining for 8-12 people Multiple activity zones (dining, lounging, cooking) Wedding and event hosting Outdoor kitchen and entertainment center Pool deck extension

Pro Tips

  • Design distinct zones by positioning large furniture pieces to create natural boundaries between dining and lounging areas
  • Consider adding built-in features like bench seating or planters to maximize functionality without cluttering the space
  • Install adequate lighting zones to support evening entertaining across the entire deck area

Frequently Asked Questions

How many people can this deck accommodate for a party?
A 16×20 deck can comfortably host 15-20 people for a standing party or 8-12 people for a seated dinner. The large size allows for natural crowd flow and multiple conversation areas.
Do I need special permits for a deck this size?
Most municipalities require building permits for decks over 200 square feet or 30 inches high. A 320 square foot deck typically requires engineered plans, foundation inspections, and final approval before use.
What's the structural difference compared to smaller decks?
This size requires additional support beams, more footings (typically 12-15), and potentially larger joist sizes. The span may require intermediate beam support and upgraded hardware for safety.

A Short Story

Sarah stands at the edge of her grandmother's 16×20 foot deck, watching the old woman's weathered hands sort through decades of family photographs spread across the weathered planks. Each image represents a thread in their shared tapestry—christenings, graduations, quiet Sunday dinners. "Burn them," her grandmother says, her voice carrying the authority of matriarch and legal guardian. "All of them. Before the lawyers come tomorrow." The deck suddenly feels impossibly small, its 16-by-20 dimensions shrinking around Sarah like a wooden cage. Her grandmother's secret has unraveled everything—the photos aren't just memories, they're evidence of a family built on lies that protected someone who should have faced justice long ago. "These are our history," Sarah whispers, kneeling beside a picture of her grandfather teaching her to fish. "History can be rewritten," her grandmother replies. "But only if you help me." Sarah's fingers hover over the matchbox her grandmother has placed beside the photographs. The deck boards creak beneath her knees as she realizes that preserving her family's tapestry means

daughter Tapestry The Impossible Demand

Quick Reference: 16×20 in Different Units

320
sq feet
46,080
sq inches
35.6
sq yards
29.7
sq meters