Deck dimensions
Length runs along the house, on the ledger. Width is how far the deck comes out — and that is the distance the joists have to span.
Framing summary
Deck is over 30" above grade — a 36" guard/railing is required on open sides.
- Ledger: 1/2" lag screws at 12" OC, staggered (DCA-6 Table 5 for a 12.0 ft joist span). That assumes an unknown house band joist; confirmed 2x solid-sawn lumber allows 15" OC.
- Mid-span blocking shown (1 row, 2x10). Also block solid over intermediate beam lines, under every railing post, at deck-board butt joints, and at the mid-span of any stepped / shortened joist runs.
Materials list
| Item | Qty | Unit |
|---|---|---|
| Joists 2x10 @ 16" OC Span 12.0 ft | 13 | pcs @ 12 ft |
| Beam 2-ply 2x12 1 beam line(s), 1 segment(s), posts ≤ 8.0 ft OC | 2 | pcs — 16 lf built |
| Blocking 2x10 (mid-span) 1 row(s) between joists; also block under railing posts and board butt joints | 12 | pcs |
| Posts 6x6 ~5 ft (height + footing/beam) | 3 | each |
| Footing pads 20" dia x 8" thick center post. Bear on undisturbed soil below the local frost line — depth is set locally, confirm with the building department. Pier/stem above the pad: 12" dia — the pad is the BEARING dimension, not the tube. | 1 | each |
| Footing pads 14" dia x 6" thick end posts | 2 | each |
| Concrete (60 lb bags, est.) 2.51 cu ft of pads + stems. Footings sized on the presumptive 1500 psf soil bearing (IRC Table R401.4.1, clay/silt). No soil test assumed — a tested or surveyed value may allow smaller footings. | 6 | bags |
| Ledger board 2x10 PT No.2 pressure-treated, at least as deep as the joists (min 2x8). Flashing required over the ledger. | 16 | lf |
| Ledger lags / bolts 1/2" dia 12" OC, staggered per DCA-6 Table 5 for a 12.0 ft joist span. Assumes the house band joist is unknown (1" LVL row). If it is confirmed 2x solid-sawn lumber, Table 5 allows 15" OC. | 17 | each |
| Joist hangers At the ledger wall(s) | 13 | each |
| Decking — composite 5.5" boards + 12% waste | 192 sf | ~470 lf |
| Hidden/face fasteners Per decking system | 192 sf | coverage |
| Guard / railing Guard required (>30" above grade). ~8 rail posts @ ≤6 ft OC, 36" min height | 40 | lf |
| Fascia / rim trim | 40 | lf |
| Post bases / anchors | 3 | each |
| Stairs (to grade) Rise ≤7¾", run ≥10" (Model IRC (no local amendments)) — 3.0 ft drop. Stringers ≤12" OC for composite treads. Omit if no steps to grade — or draw the real stairs on the layout. | 5 risers | 5 stringers / 4-ft width |
Watch for
- No jurisdiction selected, so no frost depth is being priced — the dig depth and the stem concrete are not in these numbers.
Ask before you dig
No frost depth is priced yet — pick where it is being built. Soil is assumed at the presumptive 1,500 psf. Below are cheaper ways to build the same deck. None of them is applied. Each needs an answer from the building department first, and the exact question is written out for you.
Better soil carries more per square foot, so the pads shrink.
Saves 0.66 cu ft of concrete (1 bag) — in materials, not dollars: your concrete and excavation rates are not assumed.
Blocked by: A soil value better than the 1,500 psf presumptive needs a SOURCE the department will take — the USDA soil survey for the parcel (free), a geotechnical report, or a field call by the official at the open-hole inspection. An override with no source is not defensible, so the plan keeps pricing 1,500 psf until one exists.
We have sized these footings on the presumptive 1,500 psf. Will you accept the USDA soil survey value for this parcel, or a field call at the open-hole inspection, instead — and if so what do you want to see in writing?
Call: Your local building department
No jurisdiction selected, so there is no department to name. Pick one to get the number and the right question.
about 60-75% of a poured pier. No truck or mixer access, cold weather, or a schedule that cannot absorb a cure. Two advantages over composite: real dead load resisting uplift, and a threaded insert to bolt a post base on. Those ratios come from the cost research, where every dollar figure was aggregator-sourced and unverified — use them to order the options, and price from your own job history.
No concrete or dig saving claimed: it changes the method, and never to one that pours more concrete than this deck does now.
Blocked by: Nothing blocks it on this deck, but it comes with conditions: This is an APPROVAL, not a listing: you are asking the official to accept it under R507.3 "other approved structural systems" on dimensions matching Table R507.3.1 — diameter AND thickness. Do NOT lean on footnote (f) ("minimum thickness shall only apply to plain concrete footings"): that is a 2021 IRC addition — check which IRC edition this jurisdiction enforces before relying on it. A pad thinner than the table needs a published rating or an engineer’s stamp. Soil condition is not established. A bearing pad needs undisturbed NATIVE soil — confirm it at the open-hole inspection. The post runs down the hole to the pad and is backfilled, so its buried length is in ground contact: UC4A (Ground Contact) treatment, not UC3B (Above Ground) — read the end tag. Hand the inspector: Dimensions matching IRC Table R507.3.1 (diameter AND thickness) — or a rating/stamp if thinner; The unit’s spec sheet: concrete strength, reinforcement, weight, insert.
We are planning precast concrete pad ("cookie") footings on this deck under IRC R507.3 "other approved structural systems" — an APPROVAL by the building official, not a listing. Do you accept that detail on these dimensions, and what do you want in the submittal?
Call: Your local building department
No jurisdiction selected, so there is no department to name. Pick one to get the number and the right question.
Code baseline (verify locally)
What this doesn't cover
- Hot tubs, planters, a roof — anything heavy in one spot. Every size here comes from tables built for 40 psf live load and 10 psf dead load, spread evenly. A concentrated load needs framing and footings designed for it, and these numbers are not that.
- Ground snow over 40 psf. DCA-6, the guide these tables come from, says it does not apply to decks that see snow loads over 40 psf. Berrien County's ground snow load is 50, so this page gives no footing sizes there — ask the building department what snow load they want a deck there designed for before you rely on any size.
- Call 811 before you dig. It's free, it's required in both Indiana and Michigan, and it needs two to three working days' notice. Start it when you price the job, not the morning you break ground.
- Product names are there so you can check the numbers. Where a footing type is rated by an evaluation report, the results name the report and the product its numbers were checked against. Breeze is not affiliated with those makers, the names belong to their owners, and naming one isn't a recommendation — install to the maker's instructions and the report's conditions.
Powered by Breeze — quoting and takeoff software built by a working contractor. This calculator is planning-grade only, not an engineered design. Verify spans, footing depth, and permit requirements with your local building department before building.