Platform deck plan

What the materials cost

Pressure-treated decking (Economy) and composite decking (Durable) on the same framing, from the plan's own shopping list (12' x 12').

Plan specifications & limitations

• Joist span

  2x10 at 16 in: at most 13' (DCA 6 Table 2, weakest species group)

  In this plan: 11' 3 1/2" · Source: web-media.awc.org

• Beam span

  2-2x10: at most 5' 8" for this joist span (DCA 6 Table 3A)

  In this plan: 5' between posts · Source: web-media.awc.org

• Beam overhang

  At most a quarter of the beam span (1' 5")

  In this plan: 1' · Source: web-media.awc.org

• Joist hangers

  Joists hang between the beams, flush with the tops; never from both sides of one beam

  In this plan: Two beams per level, front and back · Source: web-media.awc.org

• Decking

  1-1/4 in wood decking over 3+ joists at most 16 in apart; composite per its label

  In this plan: 16 in joist spacing · Source: codes.iccsafe.org

• Posts

  6x6 minimum, on post bases (lateral restraint at the base)

  In this plan: 10 3/4" posts, 1" standoff · Source: web-media.awc.org

• Footings

  Round size by the post's area (Appendix B Table B3); at least 12 in below grade, or below the frost line

  In this plan: 12 in / 16 in round, 12 in deep · Source: web-media.awc.org

• Guards

  Required where the deck is more than 30 in above grade

  In this plan: 24 in: no guard needed (we stop at 28 in) · Source: codes.iccsafe.org

• Stair risers and treads

  Risers at most 7.75 in, treads at least 10 in, 36 in wide

  In this plan: 4 x 6 in risers, 11.125 in treads, 4' wide · Source: codes.iccsafe.org

• Stair stringers

  2x12, cut stringers at most 18 in apart

  In this plan: 4 stringers · Source: web-media.awc.org

• Handrail

  Required from 4 risers, 34-38 in high, graspable

  In this plan: Included · Source: codes.iccsafe.org

• Free-standing lateral bracing

  DCA 6 does not cover free-standing decks; posts here are short (under 2 ft)

  In this plan: Post bases and post caps · Source: Our design choice

• Loads

  Sized for 40 psf live + 10 psf dead load, the DCA 6 assumption. Check local snow, wind and frost depth with your building department. Frost depth varies by location: check your local code before you dig.

• Free-standing only

  The deck stands on its own posts and footings and is never attached to the house. DCA 6 does not cover free-standing decks, so ask your building department about lateral bracing where you live.

• Height and guards

  At most 28 in above grade, so no guard is needed (guards are required above 30 in). Do not raise the deck later without a new plan.

• Footings

  Round concrete footings on undisturbed soil, at least 12 in deep or below the frost line. Never set the posts on an existing patio slab.

• Permits and HOA

  Many cities and counties require a permit for structures above 120 sq ft. Some require one for smaller ones. Many places need a permit for a deck or a pergola; HOA rules may limit size, height or color. Checking permits, setbacks and HOA rules is your responsibility.

• Not an engineered plan

  The plan is a general guide built from published prescriptive tables. It is not stamped or engineered, and it is not a substitute for engineering or local approval.