Drag an orange dot to resize; a dashed line shows when it snaps to a common size. Click a dot, then use the arrow keys to nudge 1/8″ (hold Shift for 1″). Every size can also be typed in the panel.
Checks
- The rafter passes the sag check.
- The beam passes the sag check.
- 224 sq ft under the rafters. Many towns need a permit for structures this size (over 200 sq ft). Ask before you build.
- Posts are 168″ apart, over 10 ft, so they are 6×6.
- Beams are doubled 2x12 to carry the 162 1/2″ span.
- A freestanding pergola racks without bracing. Knee braces at every post are included; do not skip them.
- Footings are 36″ deep, a typical frost depth. Enter your town’s frost depth.
- Site rules shown are typical, not your town’s. Confirm with the building department before you build.
Shopping list
| Qty | Item | Est. |
|---|---|---|
| 4 | 6×6 pressure-treated post, 12′ (board) | $201.60 |
| 1 | 6×6 pressure-treated post, 10′ (board) | $42.00 |
| 4 | 2×12 pressure-treated, 16′ (board) | $166.40 |
| 15 | 2×6 pressure-treated, 16′ (board) | $240.00 |
| 56 | 2×2 pressure-treated, 8′ (board) | $268.80 |
| 17 | Concrete mix, 80 lb bag (0.6 cu ft) (bag) | $110.50 |
| 4 | 12″ concrete form tube, 4′ (each) | $76.00 |
| 8 | Crushed gravel (0.5 cu ft bag) | $48.00 |
| 4 | 1/2″ × 10″ J-bolt anchor with nut and washer (each) | $8.00 |
| 4 | 6×6 post base, galvanized (each) | $96.00 |
| 8 | 1/2″ × 10″ galvanized carriage bolt, nut and washers (each) | $32.00 |
| 30 | Hurricane tie (galvanized) (each) | $36.00 |
| 3 | 5/16″ × 6″ structural wood screws (box of 12) | $72.00 |
| 2 | 2 1/2″ deck screws (box of 350) | $70.00 |
About $1467 · rough estimates, check the store
Parts
| Part | Qty | Length | Width | Material | |
|---|---|---|---|---|---|
| A | Post | 4 | 104 1/4″ | 5 1/2″ | 6×6 pressure-treated post |
| B | Beam ply | 4 | 192″ | 11 1/4″ | 2×12 pressure-treated |
| C | Rafter | 15 | 168″ | 5 1/2″ | 2×6 pressure-treated |
| D | Knee brace, beam Cut both ends at 45°, parallel. | 4 | 24″ | 5 1/2″ | 6×6 pressure-treated post |
| E | Knee brace, rafter Cut both ends at 45°, parallel. | 4 | 29 3/4″ | 5 1/2″ | 6×6 pressure-treated post |
| F | Shade slat | 56 | 96″ | 1 1/2″ | 2×2 pressure-treated |
Cut list
4 × 6×6 pressure-treated post, 144″ → A 104 1/4″ · E 29 3/4″ each
6×6 pressure-treated post, 120″ → D 24″ · D 24″ · D 24″ · D 24″
4 × 2×12 pressure-treated, 192″ → B 192″ each
15 × 2×6 pressure-treated, 192″ → C 168″ each
56 × 2×2 pressure-treated, 96″ → F 96″ each
Kerf 1/8″ included. Every cut runs edge to edge.
Steps
- Tape measure
- Speed square
- Pencil
- Drill/driver
- Clamps
- Safety glasses
- Hearing protection
- Dust mask
- Circular saw or miter saw
- Miter saw, or circular saw in two passes, for 4×4 posts
- Sander, 120 and 180 grit
1Before you start
Read every step once, start to finish, before you buy or cut anything. Each step names the parts it uses by letter; the parts list gives their sizes.
Set up somewhere flat with good light. A pair of sawhorses with a sheet of plywood on top makes a fine work table.
Wear safety glasses whenever a tool is running, hearing protection for saws, and a dust mask for sanding and for cutting treated wood or sheet goods. Tie back long hair and loose sleeves. Keep children and pets out of the work area.
- Tip At the store, pick straight boards: hold each one up to your eye and look down its length. Skip boards that bow, twist or have big knots near the ends.
- Tip Measure twice, cut once. Most mistakes are a misread tape, not a bad cut.
2Cut and label the parts
Cut every part on the cut list. Cut the longest parts first: if one goes wrong, it can still become a shorter part.
To mark a cut, hook your tape on the end of the board, make a small V with its point exactly at the measurement, and draw a square line through the point with a speed square. Put an X on the waste side.
Cut on the waste side of the line, so the blade's kerf (about 1/8″) comes out of the scrap, not your part.
Write each part's letter in pencil on a face that won't show, and stack the parts by letter.
Sand the faces before assembly while they're flat and easy to reach: 120 grit, then 180.
✓ Lay the parts out and count them against the parts list. Measure a few: if one is off by more than 1/16″, recut it now.
STOP. Let the saw reach full speed before it touches the wood, keep both hands clear of the blade's path, and never reach under a board you're cutting. Support long boards on both sides of the cut so the blade doesn't pinch.3Lay out the posts
Mark four post centres with stakes: 162 1/2″ apart along the beams, 135 1/2″ apart across.
Measure the diagonals. Move stakes until they match.
STOP. Call 811 before you dig. Confirm with your town whether this pergola needs a permit, and the setbacks from your property lines.4Pour the footings
Dig four holes 16″ wide and 42″ deep (36″ is a typical frost depth; use your town’s). Tamp 6″ of gravel in the bottom.
Set a 12″ form tube in each, 2″ above grade, plumb. Backfill around it and fill it with concrete.
Push a J-bolt into the centre of each while wet, on the layout string. Let it cure 2 days.
✓ The J-bolt diagonals match.
5Set the posts
Bolt a post base to each footing.
Cut the four posts (A) to 104 1/4″. Screw each into its base. Brace each plumb both ways with two stakes and scrap boards.
✓ Each post is plumb on two faces and the tops are level with each other.
6Hang the beams
Clamp a beam ply (B) to each side of the posts, crown up, tops flush with the post tops, 12″ past the posts at each end.
At every post, drill through ply, post and ply and fit two 10″ carriage bolts.
✓ Both beams are level end to end and with each other.
STOP. Lifting beams overhead takes two people and stable ladders.7Set the rafters
Mark 15 rafter centres on both beams: one over each post, 13 9/16″ apart between the posts, 14″ apart out to the beam ends.
Stand the rafters (C) on edge across the beams, 12″ past each beam. Fix each rafter to each beam with a hurricane tie.
✓ The rafter ends line up. Snap a line and trim any that stick out.
8Add the knee braces
Along each beam: fit a brace (D) between the beam plies, from each post to the beam at 45°. Two 6″ structural screws at each end.
Across: fit a brace (E) from the inside face of each post up to the rafter over it, passing under the beam. Two 6″ structural screws at each end.
✓ Remove the temporary stakes. Push a post hard: the frame should not lean.
9Lay the shade slats
Lay 28 rows of slats (F) across the rafters, 6 3/16″ apart on centre, the first and last flush with the rafter ends, two slats per row joined over the middle rafter.
One 2 1/2″ deck screw at every rafter.
10Finish
Ease every sharp edge and corner with 120-grit sandpaper so nobody gets a splinter.
Sand all over with 180 grit, always along the grain (the direction the wood fibres run). Scratches across the grain show through stain.
Wipe off the dust with a barely damp rag and let it dry.
Outdoors, use an exterior finish: a penetrating deck oil or exterior stain, or primer and exterior paint. Leave cedar bare to weather silver if you like. If it holds soil for food plants, leave the inside unfinished.
Let it dry for the time on the can before using it.
- Tip Try your finish on a scrap of the same wood first: stain looks different on every board.
Conceptual layout, material estimate and assembly guide from the sizes you entered. Not engineering, not a building plan, not stamped or approved. Confirm measurements on site; follow local codes and product instructions; anchor tall pieces before use. Using this plan means you accept the Terms of Use.