A free 12 × 12 ft attached deck, 5/4 x 6 pressure-treated plan designed to the Ontario Building Code 2024, Part 9: 2x8 @ 16 in o.c. joists, a 2-ply 2x10 beam and 6x6 posts on 16 in dia. round, 48 in deep footings, about $1,711 in materials at estimated big-box prices. Blueprint, 3D model, materials list, code check and build steps.
| Joists | 2x8 @ 16 in o.c. |
|---|---|
| Beam | 2-ply 2x10 |
| Posts | 6x6 |
| Footings | 16 in dia. round, 48 in deep |
| Ledger | 2x8 (2x8 minimum, at least as deep as the joists) |
A rectangular deck of 144 sq ft attached to the house with a ledger, 2x8 joists at 16 in on center on 1 beam line. The surface sits 36 in above grade. 24 items in the list below, every one with its quantity and why.
Where these numbers come from. The deck's guard, footing depth and post size follow the Ontario Building Code 2024, Part 9, with its article numbers. Member sizes and footing diameters use US prescriptive tables (IRC 2021 Section R507, No. 2 lumber at 40 psf live and 10 psf dead load) until licensed Canadian tables are added; confirm them with your building department. Those table values are still being checked line by line against the code book. Snow: the calculator doesn't know your town, so it uses Part 9's minimum deck load of 1.9 kPa (40 psf) (OBC 9.4.2.3). A town with heavy snow can need more, so have yours checked; the full planner looks it up. Treat the result as a starting point and confirm your design with your local building department before you build.
| Qty | Item | Each | Total |
|---|---|---|---|
| Lumber | $592.48 | ||
| 1 each | 2 in. x 4 in. x 10 ft. #2 Prime Ground Contact Pressure-Treated Lumber2 rails at 4'-9.5" → 1 board cut 4'-9.5" + 4'-9.5" (5" total offcut). | $7.98 | $7.98 |
| 2 each | 2 in. x 4 in. x 14 ft. #2 Prime Ground Contact Pressure-Treated Lumber2 rails at 12'-3.5" → 2 boards cut 12'-3.5" (3'-5" total offcut). | $11.28 | $22.56 |
| 2 each | 2 in. x 4 in. x 16 ft. #2 Prime Ground Contact Pressure-Treated Lumber2 rails at 11'-8.5", 2 rails at 4'-2.5" → 2 boards cut 11'-8.5" + 4'-2.5" (1.75" total offcut). | $12.98 | $25.96 |
| 12 each | 2 in. x 8 in. x 12 ft. #2 Prime Ground Contact Pressure-Treated Lumber1 ledger at 12'-0", 3 rim joists at 12'-0", 8 joists at 11'-9" → 4 boards cut 12'-0"; 8 boards cut 11'-9" (2'-0" total offcut). | $15.98 | $191.76 |
| 2 each | 2 in. x 10 in. x 12 ft. #2 Prime Ground Contact Pressure-Treated Lumber2 beam plies at 12'-0" → 2 boards cut 12'-0" (0" total offcut). | $21.98 | $43.96 |
| 2 each | 2 in. x 12 in. x 10 ft. #2 Prime Ground Contact Pressure-Treated Lumber4 stair stringers at 4'-2.25" → 2 boards cut 4'-2.25" + 4'-2.25" (3'-2.25" total offcut). | $24.98 | $49.96 |
| 4 each | 4 in. x 4 in. x 8 ft. #2 Ground Contact Pressure-Treated Timber8 guard posts at 3'-6.75" → 4 boards cut 3'-6.75" + 3'-6.75" (3'-5.5" total offcut). | $12.98 | $51.92 |
| 1 each | 6 in. x 6 in. x 8 ft. #2 Ground Contact Pressure-Treated Timber3 posts at 1'-6.5" → 1 board cut 1'-6.5" + 1'-6.5" + 1'-6.5" (3'-4.25" total offcut). | $39.98 | $39.98 |
| 80 each | 2 in. x 2 in. x 36 in. Pressure-Treated Square-End Baluster34'-2" of top rail ÷ 5.25 in (1.5 in baluster + 3.75 in clear, under the 4 in sphere rule) = 80 balusters. | $1.98 | $158.40 |
| Decking | $377.32 | ||
| 2 each | 5/4 in. x 6 in. x 8 ft. Premium Pressure-Treated Decking Board26 boards in 26 rows across 144 sq ft, joints over joists and staggered; 8 tread boards. 2 tread boards at 3'-0" → 1 board cut 3'-0" + 3'-0" (2'-0" total offcut). 1 boards +10% for culls and end damage = 2. | $7.98 | $15.96 |
| 3 each | 5/4 in. x 6 in. x 10 ft. Premium Pressure-Treated Decking Board26 boards in 26 rows across 144 sq ft, joints over joists and staggered; 8 tread boards. 6 tread boards at 3'-0" → 2 boards cut 3'-0" + 3'-0" + 3'-0" (1'-11.5" total offcut). 2 boards +10% for culls and end damage = 3. | $9.48 | $28.44 |
| 29 each | 5/4 in. x 6 in. x 12 ft. Premium Pressure-Treated Decking Board26 boards in 26 rows across 144 sq ft, joints over joists and staggered; 8 tread boards. 26 decking boards at 12'-0" → 26 boards cut 12'-0" (0" total offcut). 26 boards +10% for culls and end damage = 29. | $11.48 | $332.92 |
| Concrete | $209.40 | ||
| 30 bag | Quikrete 80 lb. Concrete Mix3 footings (16 in × 48 in = 5.59 cu ft → 10 bags each); an 80 lb bag yields 0.6 cu ft. | $6.98 | $209.40 |
| Hardware | $227.31 | ||
| 10 each | Simpson Strong-Tie LUS ZMAX Galvanized Face-Mount Joist Hanger for 2x8One per joist end at the ledger: 10 2x8 joists and side rims frame into it. | $1.98 | $19.80 |
| 20 each | Simpson Strong-Tie H2.5A ZMAX Hurricane TieTwo per joist at each beam crossing (one each side) for uplift: 10 crossings × 2. | $0.88 | $17.60 |
| 3 each | Simpson Strong-Tie ABA ZMAX 6x6 Adjustable Post BaseOne per 6x6 post on a concrete footing (3); keeps end grain off the concrete. | $18.47 | $55.41 |
| 3 each | Simpson Strong-Tie BC ZMAX Galvanized Post Cap for 6x6One per 6x6 post carrying a beam (3) to tie the beam down. | $14.98 | $44.94 |
| 4 each | Simpson Strong-Tie LSCZ ZMAX Adjustable Stair-Stringer ConnectorOne per stair stringer (4) at the rim. | $7.48 | $29.92 |
| 16 each | 1/2 in. x 8 in. Hot-Dip Galvanized Carriage Bolt with Nut and WasherTwo through-bolts per guard post: 8 posts × 2. | $2.48 | $39.68 |
| 2 each | 10 ft. Galvanized Steel Z-Flashing12'-0" of ledger with 6 in laps between 10 ft pieces = 2. | $9.98 | $19.96 |
| Fasteners | $229.85 | ||
| 1 box | FastenMaster LedgerLOK 3-5/8 in. Ledger Board Screw (50-pack)12'-0" of ledger, 2 staggered rows at 16 in o.c. = 20 screws → 1 × 50-pack. | $49.97 | $49.97 |
| 3 box | Simpson Strong-Tie SD9112 #9 x 1-1/2 in. Connector Screws (100-pack)Screws for hangers (10 × 10) + ties (5 × 20) + post bases (8 × 3) + caps (12 × 3) + stringer connectors (10 × 4) = 300. | $24.98 | $74.94 |
| 3 box | 2-1/2 in. Coated Deck Screws (5 lb box)26 rows × 10 joists × 2 + 8 tread boards × 4 stringers × 2 = 584 decking screws; 80 balusters × 4 = 320 → 904 screws at ~450 per box = 3. | $34.98 | $104.94 |
| Misc | $74.94 | ||
| 3 roll | Self-Adhesive Joist Tape 1-5/8 in. x 50 ft12 joists, rims and beams ≈ 142 ft of tops ÷ 50 ft rolls = 3. | $24.98 | $74.94 |
| Estimated total, before tax | $1,711.30 | ||
Prices are illustrative big-box estimates in US dollars, not a quote. Open the plan in 16Span to look up prices at your own store.
| Role | Size | Species / grade | Span / load | Checked against |
|---|---|---|---|---|
| Joists | 2x8 @ 16 in o.c. | Southern Pine #2, pressure-treated | 11 ft 4.5 in ledger-to-beam + 0 ft 4.5 in cantilever | IRC 2021 Table R507.6: 2x8 Southern Pine @ 16 in allows 11 ft 10 in; design spans 11 ft 4.5 in — OK, 0 ft 5.5 in margin. (table values not yet verified against the code book) |
| Beam | 2-ply 2x10 | Southern Pine #2, pressure-treated | max post spacing 5 ft 9.25 in; effective joist span 12 ft 1.75 in (span plus cantilever, by joist reaction) | IRC 2021 Table R507.5: 2-ply 2x10 Southern Pine at the 14 ft joist-span column allows 6 ft 9 in between posts; design has 5 ft 9.25 in — OK, 0 ft 11.75 in margin. (table values not yet verified against the code book) |
| Posts | 6x6 | Southern Pine #2, pressure-treated | tallest post 1 ft 6.5 in, top of footing to underside of beam | IRC 2021 Table R507.4: 6x6 Southern Pine posts may be up to 14 ft 0 in tall; tallest is 1 ft 6.5 in — OK, 12 ft 5.5 in margin. OBC 2024 9.17.4.1: 6x6 posts (140 × 140 mm) meet the 140 × 140 mm minimum and are at least as wide as the beam. No lateral bracing is needed: the posts are 600 mm or less from the ground to the beam and carry a deck with no superstructure (OBC 9.17.2.2.(3)). (table values not yet verified against the code book) |
| Footings | 16 in dia. round, 48 in deep | Concrete; assumes 1500 psf soil bearing | tributary area 35 sq ft per footing ≈ 1,749 lb at 50 psf | IRC 2021 Table R507.3.1 (1500 psf soil): the 40 sq ft column needs a 16 in round footing; design has 16 in — OK, 0 in margin. (table values not yet verified against the code book) |
| Ledger | 2x8 (2x8 minimum, at least as deep as the joists) | Southern Pine #2, pressure-treated | carries the house end of joists spanning 11 ft 4.5 in | OBC 2024 Part 9 has no prescriptive rule for fastening a deck ledger to a house: use an engineered or building-department-accepted ledger detail. For reference only, the US IRC 2021 R507.9 schedule: IRC 2021 Table R507.9.1.3(1) at the 12 ft joist-span column: 1/2 in lag screws at 15 in o.c. or through-bolts at 29 in o.c., staggered in two rows. Fasten to the house rim joist only (not brick or stone veneer), with flashing above. (table values not yet verified against the code book) |
None — the numbers close.
Code and structural values are AI-generated from published tables and can be wrong or out of date. Confirm anything marked “Verify” with your local building department before you dig. Read the safety disclaimer.
Each phase builds on the one before, so there is always something solid to fix to.
Every later measurement comes off the layout, so set it out and square it before digging.
Posts must be plumb and cut to height before a beam can go on.
The beams have to be in place and level before any joist can span to them.
Joists carry the decking to the beams; the rims close the frame so it holds its shape.
Decking goes on once the frame is complete and square to lay against.
The surface is 914 mm (36 in) above grade, so the open sides need a guard before the deck is used (OBC 9.8.8.1).
Stairs go last so the stringers can hang from the finished rim.
Open this plan in 16Span and ask for changes in plain words, like "make it 2 ft deeper" or "add stairs on the left". The structure is checked again, and the materials and price follow.