Deck
Outdoor & decks

Deck or balcony

DIY OK
Footings, posts, beams, joists and decking for a deck, or a balcony on posts, with the railing it needs.
Sheet A-1 · Deck

12′ × 12′ deck

DIY OK
Deck
144
sq ft · 12′ × 12′
Footings
2
16″ × 36″ deep
Joists
10
2×8 at 16″ o.c.
Beam
3-2×12
2 posts, 10′ apart
Deck boards
28
5/4×6
32–49 h of work
Two to four weekends: the footings need a few days before you build on them.
Draft
The rules behind this Sheet are waiting for a licensed pro’s sign-off.
Permit likely needed
Decks need a building permit unless they are small, low and freestanding: the IRC (R105.2) exempts only 200 sq ft or less, 30″ or less above the ground, not attached and not serving the main door. This one is 144 sq ft, 3′ up, attached. Expect footing, framing and final inspections. Confirm with your building department.
Frost depth
Footings go below the frost line: your building department sets the depth, and footings go at least 12″ below undisturbed ground either way. This Sheet plans 36″ — set Footing depth to your town’s number.
Call 811 first — it’s the law
Call 811 a few business days before digging (your state sets the wait). Free. Wait for the utility markings.
Guards required
Open sides more than 30″ above the ground need a guard 36″ tall with openings under 4″ (IRC R312); some towns ask 42″. About 33′ of guard on this deck (three open sides, less 36″ per stair): the Railings and guards Sheet counts the posts, rails and balusters.
Stairs: one run
Each set of steps comes down 3′: the Deck stairs Sheet lays out the stringers, treads, landing and handrail for that rise.

Drawing

Framing plan + section
1
Ledger Bolted to the house’s band joist, flashed.
2
Joists 2×8 at 16″ on center, in hangers at the ledger.
3
Beam 3-2×12 under the joists (dashed).
4
Post + footing 6×6 post on a 16″ footing.
5
Rim Across the joist ends, 3 screws each.
6
Decking Boards across the joists.
7
Guard On the open sides: 36″ tall.
8
Footing 16″ pad, 6″ thick, on undisturbed soil.
9
Hanger Joist hanger at the ledger.
Plan to scale; the section is not to scale across. Beam and posts dashed: they sit under the joists.

What to buy

24 items · 2 if needed
Save to your jobs to check things off in the store.
Lumber
Posts
Pressure-treated 6×6 post · 6×6 × 8′
2 posts
Heavy post for gates, tall fences and porch or deck posts. Buy it rated for ground contact if it goes in the ground.
Beam
Pressure-treated 2×12 · 2×12 × 12′
3 boards
Stringer stock. The deck guide (DCA 6) calls for 2×12 minimum.
Joists
Pressure-treated 2×8 · 2×8 × 12′
10 boards
Joists, ledger, rim and blocking, actually 1½″ × 7¼″. Rated for ground contact or above ground — the tag says which.
Rim joist
Pressure-treated 2×8 · 2×8 × 12′
1 board
Joists, ledger, rim and blocking, actually 1½″ × 7¼″. Rated for ground contact or above ground — the tag says which.
Ledger
Pressure-treated 2×8 · 2×8 × 12′
1 board
Joists, ledger, rim and blocking, actually 1½″ × 7¼″. Rated for ground contact or above ground — the tag says which.
Blocking
Pressure-treated 2×8 · 2×8 × 12′
1 board
Joists, ledger, rim and blocking, actually 1½″ × 7¼″. Rated for ground contact or above ground — the tag says which.
Mid-span blocking (optional)
If needed
Pressure-treated 2×8 · 2×8 × 12′
1 board
Keep the receipt — return it if you don’t use it.
Joists, ledger, rim and blocking, actually 1½″ × 7¼″. Rated for ground contact or above ground — the tag says which.
Decking
5/4×6 treated deck board · 5/4×6 × 12′
28 boards
Tread boards, 1″ thick × 5½″ wide.
Fasteners
Threaded rod ½″ × 3 ft with nuts and washers
2 rods
Joins the tension tie on the deck joist to the one on the house’s floor joist, through the band joist.
Lag screws ½″ with washers (hot-dip galvanized)
½″ × 4″ + washer
11 screws
Fasten the ledger to the house’s band joist. Long enough that the tip passes through the band joist.
Framing
Coated deck screws · 3″ coated
≈174 (2 boxes of 100)
Exterior-rated screws for treads and risers.
Decking
Coated deck screws · 2½″ coated
≈520 screws (6 boxes of 100)
Exterior-rated screws for treads and risers.
Hardware
Post base or anchor
6×6 standoff, galvanized
2 bases
Galvanized base set in or bolted to the pier that holds the post off the concrete. Use what your plans or the post’s load call for.
Anchor bolt ⅝″ with nut and washer
⅝″, J-bolt or wedge anchor
2 bolts
Holds the post base to the footing: a J-bolt set in the wet concrete or a wedge anchor drilled in later.
Post-to-beam connector (post cap)
for 6×6 and a 3-ply beam
2 caps
Galvanized cap that ties the beam to the top of the post, sized for the post and the beam’s plies.
Joist hangers
for 2×8, G185 or stainless
10 hangers
Galvanized (G185) or stainless brackets that hold each joist on the ledger or beam. Sized to the joist; fill every nail hole.
Hurricane ties (joist to beam)
galvanized
10 ties
Small galvanized ties that hold each joist down on the beam and keep it from sliding.
Deck tension tie, 1,500 lb (for example Simpson DTT2Z)
1,500 lb rated
4 ties
Hold-down that ties the deck’s joists to the house’s floor framing so the deck can’t pull away.
Z-flashing, 10 ft
2 pieces
Metal or vinyl cap over the top of the ledger: siding laps over it, water drips off in front of the ledger.
Self-adhered flashing tape, 6″ × 75 ft
1 roll
Rubberized tape that seals the wall behind the ledger and around every bolt hole.
Connector fasteners
hanger nails or connector screws
≈280 (3 boxes of 100)
Use exactly what the connector maker specifies.
Joist tape, 50 ft
If needed
50 ft rolls
3 rolls
Keep the receipt — return it if you don’t use it.
Butyl tape on the tops of joists, rim and beam: keeps water out of screw holes. Most composite makers recommend it.
Concrete & landscape
Footings
Concrete mix, 80 lb · 80 lb bags
11 bags
About 0.6 cu ft per bag.
Concrete form tube
12″ × 4′
2 tubes
Cardboard tube that forms a round footing or pier; cut to length with a handsaw.

Tools

You own 0 of 22 must-haves
Tap the ones you already own. That builds your Tool Shed as you go — no setup.

Must have

The job stalls without it.

Rent it

Costly to buy for one job. Rent it for a day.

Nice to have

Faster or cleaner, not required.

Order of work

32–49 h of work
01
Get the building permit from your local building department: bring a plan like this Sheet’s. Most inspect the footing holes, the framing and the finished deck.
02
Call 811 a few business days before you dig and wait for the utility marks — it’s free.
Check first
Utility marks in place before the first hole — photograph them.
03
Mark the ledger line: the deck boards land 1–2″ below the door sill. Cut the siding away, and tape the wall behind the ledger with flashing tape.
04
Fasten the ledger to the band joist with ½″ lag screws, staggered top and bottom; Z-flashing over the top, siding back down over the flashing. Never into brick, stone or a cantilevered floor.
Check first
Flashing tape on the wall behind the ledger, Z-flashing over it, siding lapped over the flashing.
It’s the house’s band joist behind the siding — not brick, stone or overhanging floor joists.
05
Lay out the posts with string lines from the ledger and batter boards: square the corners until the diagonals match within ¼″.
Check first
Diagonals within ¼″ of each other before you dig.
06
Dig 2 footing holes 16″ across and 36″ deep, down to undisturbed soil below the frost line.
Check first
Every hole on undisturbed soil below the frost line; holes within 5 ft of the house go as deep as its footing.
07
Footing inspection: most towns check the holes before you pour.
08
Pour each footing: the 16″ pad, then the 12″ form tube to 2″ above the ground; set the post-base anchor in the wet concrete, lined up with the string.
Check first
Footing inspection passed (if your town inspects the holes).
Wait 2–3 days — footings cure before they carry the frame
Keep the concrete damp and leave it alone: most bagged mixes take the posts and beam after 2–3 days (longer in the cold) — see the bag. Cut boards and stage the lumber meanwhile.
09
Stand the posts in their bases and brace them plumb. Mark the beam height level from the ledger, cut the posts, and set the beam on post caps (plies screwed in two rows every 16″).
10
Hang the joists 16″ on center, crown up: hangers at the ledger, every hole nailed, hurricane ties at the beam and blocking between the joists over it.
Check first
The hanger maker’s nails in every hole — not deck screws.
11
Fasten the rim across the joist ends (3 screws per joist); check the frame square and level.
12
Install the lateral-load ties: two connections within 24″ of the deck’s ends, through the band joist to the house’s floor joists.
13
Framing inspection before the decking goes on.
14
Lay the deck boards across the joists, ⅛″ gaps, 2 screws at every joist; every board end on a joist, joints staggered.
Check first
Framing inspection signed off before the first board.
Every board end over a joist; doubled joists where ends meet.
15
Build the stairs with the Deck stairs Sheet (3′ rise).
16
Install the guards before anyone uses the deck: about 33′, 36″ tall — the Railings and guards Sheet counts them.
Check first
Guards on before anyone uses the deck.
17
Final inspection.

Mistakes that ruin the job

5 mistakes
1
No flashing over the ledger
Water gets behind the ledger and rots the house’s band joist — the most common reason decks pull off houses. Tape behind it, Z-flashing over it, siding over that.
2
Ledger on brick, stone or a cantilevered floor
A ledger must bolt to the house’s band joist. On veneer, or where the floor joists overhang the foundation, build the deck freestanding instead.
3
Footings too shallow
Above the frost line they heave every winter; within 5 ft of the house they must reach the house footing’s depth. Dig to undisturbed soil.
4
Deck screws in the hangers
Hangers and ties hold only with the nails or structural screws on their label, in every hole.
5
Board ends between joists
Every board end lands on a joist. Where two ends meet, double the joist so each end gets a full bite.

Plan it

The load

To haul
2,230 lb
from the store to the room
Helpers
1
for some steps
Heaviest
Concrete mix, 80 lb · 11 bags · 880 lb
5/4×6 treated deck board · 28 pcs · 525 lb
Pressure-treated 2×8 · 13 pcs · 485 lb
Bring a helper: unload and move materials
About 2,230 lb to move — have it delivered, or bring a helper and a hand truck or wheelbarrow.
Rent: Power auger

When you’ll finish

Pick when you can start and how many hours you have.
Hours you can work
Each weekday evening
0
h
Each weekend day
8
h
Saved for every Sheet. Waits run overnight and on days off; work only fills the hours you have.

DIY vs hiring it out

Estimate
Typical US store prices and labor rates, not a quote. A real price can differ a lot.

Do it yourself

Materials
$1,150–$1,550
Tools to buy
22 must-haves you don’t own
Tape measure (25 ft), Mason's line + stakes, Chalk line, 4-ft level, …
Rentals
1
About $40–$90 a day each
Your time
32–49 h
Total
$1,150–$1,550 + tools

Hire a pro

Materials + 15%
$1,300–$1,800
Pros mark up what they buy
Labor
17.6 h × $65–$95
$1,150–$1,650
Their time
17.6 hours
Permits
likely needed
Total
$2,450–$3,450

Before you go

0 of 8 checked
The small stuff that causes a second trip to the store.

Rules used

11 rules · Draft
Every number on this Sheet comes from these rules. A licensed pro reviews each one before a Sheet is marked verified.

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Project
Deck
Sheet
A-1
Date
Scale
Not to scale
DIY time
32–49 h
Rules
Draft — pending pro review
Other common sizes
10×10
12×16
16×20