A free 12 × 12 ft freestanding deck, 5/4 x 6 pressure-treated plan designed to the Ontario Building Code 2024, Part 9: 2x10 @ 16 in o.c. joists, a 2-ply 2x6 beam and 4x4 posts on 14 in dia. round, 48 in deep footings, about $2,314 in materials at estimated big-box prices. Blueprint, 3D model, materials list, code check and build steps.
| Joists | 2x10 @ 16 in o.c. |
|---|---|
| Beam | 2-ply 2x6 |
| Posts | 4x4 |
| Footings | 14 in dia. round, 48 in deep |
| Footings (B2) | 14 in dia. round, 48 in deep |
A rectangular deck of 144 sq ft freestanding, 2x10 joists at 16 in on center on 2 beam lines. The surface sits 36 in above grade. 21 items in the list below, every one with its quantity and why.
Where these numbers come from. The deck's guard and footing depth follow the Ontario Building Code 2024, Part 9, with its article numbers. Joists, beams and posts are sized from the CWC Prescriptive Residential Exterior Wood Deck Span Guide (2016) (incised treated lumber; 1- to 3-ply beams; 4x4 posts up to 6.5 ft, where the plan asks your building department to confirm them, since OBC 9.17.4.1 calls for 6x6); footing diameters use the US AWC DCA 6 table, for reference, since neither NBC Part 9 nor the guide has one for decks. The US reference 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), the load the guide is for. A town with heavy snow can need more: pick yours below, or have it 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. OBC 2024's Part 9 is based on NBC 2020. Joist, beam and post tables: Canadian Wood Council, Prescriptive Residential Exterior Wood Deck Span Guide (2016), designed to CSA O86-14 and NBC 2015.
| Qty | Item | Each | Total |
|---|---|---|---|
| Lumber | $749.58 | ||
| 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 |
| 1 each | 2 in. x 4 in. x 12 ft. #2 Prime Ground Contact Pressure-Treated Lumber1 rail at 11'-8.5" → 1 board cut 11'-8.5" (3.5" total offcut). | $9.48 | $9.48 |
| 3 each | 2 in. x 4 in. x 14 ft. #2 Prime Ground Contact Pressure-Treated Lumber3 rails at 12'-3.5" → 3 boards cut 12'-3.5" (5'-1.5" total offcut). | $11.28 | $33.84 |
| 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 |
| 4 each | 2 in. x 6 in. x 12 ft. #2 Prime Ground Contact Pressure-Treated Lumber4 beam plies at 12'-0" → 4 boards cut 12'-0" (0" total offcut). | $12.98 | $51.92 |
| 12 each | 2 in. x 10 in. x 12 ft. #2 Prime Ground Contact Pressure-Treated Lumber4 rim joists at 12'-0", 8 joists at 11'-9" → 4 boards cut 12'-0"; 8 boards cut 11'-9" (2'-0" total offcut). | $21.98 | $263.76 |
| 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 |
| 7 each | 4 in. x 4 in. x 8 ft. #2 Ground Contact Pressure-Treated Timber9 guard posts at 3'-8.75", 10 posts at 1'-8.25" → 4 boards cut 3'-8.75" + 3'-8.75"; 1 board cut 3'-8.75" + 1'-8.25" + 1'-8.25"; 2 boards cut 1'-8.25" + 1'-8.25" + 1'-8.25" + 1'-8.25" (5'-5.25" total offcut). | $12.98 | $90.86 |
| 109 each | 2 in. x 2 in. x 36 in. Pressure-Treated Square-End Baluster46'-5.5" of top rail ÷ 5.25 in (1.5 in baluster + 3.75 in clear, under the 4 in sphere rule) = 109 balusters. | $1.98 | $215.82 |
| 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 | $558.40 | ||
| 80 bag | Quikrete 80 lb. Concrete Mix10 footings (14 in × 48 in = 4.28 cu ft → 8 bags each); an 80 lb bag yields 0.6 cu ft. | $6.98 | $558.40 |
| Hardware | $299.36 | ||
| 40 each | Simpson Strong-Tie H2.5A ZMAX Hurricane TieTwo per joist at each beam crossing (one each side) for uplift: 20 crossings × 2. | $0.88 | $35.20 |
| 10 each | Simpson Strong-Tie ABA ZMAX 4x4 Adjustable Post BaseOne per 4x4 post on a concrete footing (10); keeps end grain off the concrete. | $11.98 | $119.80 |
| 10 each | Simpson Strong-Tie BC ZMAX Galvanized Post Cap for 4x4One per 4x4 post carrying a beam (10) to tie the beam down. | $6.98 | $69.80 |
| 4 each | Simpson Strong-Tie LSCZ ZMAX Adjustable Stair-Stringer ConnectorOne per stair stringer (4) at the rim. | $7.48 | $29.92 |
| 18 each | 1/2 in. x 8 in. Hot-Dip Galvanized Carriage Bolt with Nut and WasherTwo through-bolts per guard post: 9 posts × 2. | $2.48 | $44.64 |
| Fasteners | $229.84 | ||
| 5 box | Simpson Strong-Tie SD9112 #9 x 1-1/2 in. Connector Screws (100-pack)Screws for ties (5 × 40) + post bases (8 × 10) + caps (12 × 10) + stringer connectors (10 × 4) = 440. | $24.98 | $124.90 |
| 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; 109 balusters × 4 = 436 → 1020 screws at ~450 per box = 3. | $34.98 | $104.94 |
| Misc | $99.92 | ||
| 4 roll | Self-Adhesive Joist Tape 1-5/8 in. x 50 ft14 joists, rims and beams ≈ 166 ft of tops ÷ 50 ft rolls = 4. | $24.98 | $99.92 |
| Estimated total, before tax | $2,314.42 | ||
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 | 2x10 @ 16 in o.c. | D.Fir-L / Hem-Fir / S-P-F, No. 2 or better, pressure-treated (incised) | 3.58 m (11 ft 8.75 in) beam-to-beam + 0.01 m (0 ft 0.25 in) cantilever | CWC Deck Span Guide Table 3a, incised, No. 2 or better: 38 × 235 mm (2x10) joists at 400 mm (16 in) o.c. may span 3.92 m (12 ft 10.25 in) (Douglas Fir-Larch governs); design spans 3.58 m (11 ft 8.75 in) — OK, 0.34 m (1 ft 1.5 in) margin. No cross bridging: the guide's spans assume the decking braces the joists. |
| Beam | 2-ply 2x6 | D.Fir-L / Hem-Fir / S-P-F, No. 2 or better, pressure-treated (incised) | max post spacing 0.89 m (2 ft 11.25 in); joist span + cantilever 3.58 m (11 ft 9 in) | CWC Deck Span Guide Table 5b, incised, joist span + cantilever up to 12 ft: a 2-ply 2x6 D.Fir-L / Hem-Fir / S-P-F beam may have posts up to 1.22 m (4 ft 0 in) apart (the table lists 2-ply 2x6 at 4 ft); design has 0.89 m (2 ft 11.25 in) between post centres — OK, 0.33 m (1 ft 1 in) margin. |
| Posts | 4x4 | D.Fir-L / Hem-Fir / S-P-F, No. 2 or better, pressure-treated (incised) | tallest post 1 ft 8.25 in, top of footing to underside of beam | CWC Deck Span Guide note 5: 4x4 posts up to 2.0 m (6.5 ft) high, 6x6 up to 3.66 m (12 ft), and 6x6 under a 3-ply beam; these 4x4 posts are up to 514 mm (20.3 in) under a 2-ply beam — OK. 4x4 posts are 89 × 89 mm; OBC 9.17.4.1.(2) requires wood columns at least 140 × 140 mm unless calculations show a smaller size is adequate (the CWC guide's engineered tables allow this 4x4, so 16Span asks the building department to confirm it). 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)). |
| Footings | 14 in dia. round, 48 in deep | Concrete; assumes 1500 psf soil bearing | tributary area 21.5 sq ft per footing ≈ 1,073 lb at 50 psf | NBC Part 9 and the CWC deck guide have no deck table for footing sizes (its Table 9.15.3.4. sizes footings for building columns); for reference, the US AWC DCA 6 Appendix Table B3 (1500 psf soil): the 30 sq ft row needs a round footing at least 14 in across and 6 in thick (the footing's own weight included); design has 14 in — OK, 0 in margin. Concrete 48 in thick — OK. (from AWC DCA 6, 2015 IRC edition; IRC 2021 not yet confirmed) |
| Footings (B2) | 14 in dia. round, 48 in deep | Concrete; assumes 1500 psf soil bearing | tributary area 21.5 sq ft per footing ≈ 1,077 lb at 50 psf | NBC Part 9 and the CWC deck guide have no deck table for footing sizes (its Table 9.15.3.4. sizes footings for building columns); for reference, the US AWC DCA 6 Appendix Table B3 (1500 psf soil): the 30 sq ft row needs a round footing at least 14 in across and 6 in thick (the footing's own weight included); design has 14 in — OK, 0 in margin. Concrete 48 in thick — OK. (from AWC DCA 6, 2015 IRC edition; IRC 2021 not yet confirmed) |
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.