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
- Not for an air conditioner, heat pump or generator: those sit on the maker's pad, set by the installer.
- Fits a shed floor up to 72″ × 48″, with 12″ of gravel showing on every side to catch roof water.
- Site rules shown are typical, not your town’s. Confirm with the building department before you build.
Shopping list
| Qty | Item | Est. |
|---|---|---|
| 2 | 4×4 pressure-treated post, 8′ (board) | $25.60 |
| 1 | 4×4 pressure-treated post, 12′ (board) | $19.20 |
| 1 | 2×4 stud, 8′ (board) | $4.80 |
| 1 | Crushed gravel, delivered (cubic yard) | $60.00 |
| 1 | Landscape fabric, 4′ × 50′ (roll) | $22.00 |
| 1 | 6″ structural timber screws (box of 12) | $24.00 |
| 8 | 1/2″ rebar stake, 24″ (each) | $24.00 |
| 1 | Wood stakes, 18″ (bundle of 12) | $9.00 |
| 1 | Mason's line (nylon string), 250′ (roll) | $6.00 |
| 1 | Marking paint, upside-down spray (can) | $7.00 |
About $202 · rough estimates, check the store
Parts
| Part | Qty | Length | Width | Material | |
|---|---|---|---|---|---|
| A | Border timber, long side Ground-contact rated. | 2 | 96″ | 3 1/2″ | 4×4 pressure-treated post |
| B | Border timber, short side Ground-contact rated. | 2 | 65″ | 3 1/2″ | 4×4 pressure-treated post |
| C | Screed board Pick the straightest 2×4 in the pile. Not cut: it rides on the border to level the gravel. | 1 | 84″ | 3 1/2″ | 2×4 stud |
Cut list
2 × 4×4 pressure-treated post, 96″ → A 96″ each
4×4 pressure-treated post, 144″ → B 65″ · B 65″
2×4 stud, 96″ → C 84″
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
- Flat spade and square shovel
- Steel garden rake
- Wheelbarrow
- Hand tamper
- 4′ level
- 1/2″ drill bit at least 6″ long
- Small sledgehammer
- Garden hose with a mist nozzle
- 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.3Call 811 and check the spot
At least 3 working days before you dig, call 811 (or use call811.com). It's free. They send people to paint or flag buried gas, electric, water and cable lines near where the shed pad will go.
Check your property line on your survey or plot plan, and ask your town about setbacks, easements and whether this needs a permit.
Pick ground that drains: not a low spot where puddles sit after rain, and not over a septic field.
STOP. Don't dig until the marks are down. Hitting a gas or power line can kill you and is expensive to repair.4Mark out a square rectangle
Hammer a stake at one corner of the gravel pad. Measure 96″ along the long side and hammer a second stake. Tie mason's line tight between them, a few inches off the ground.
For the first square corner, use the 3-4-5 rule: from the first stake, mark 3 ft along the string. Run a tape 4 ft out roughly at 90°. Swing it until the 3 ft mark and the 4 ft point are exactly 5 ft apart. That direction is square: set a stake 72″ out along it.
Measure the last corner from the other two (96″ and 72″) and set the fourth stake. Run string around all four.
Measure both diagonals, corner to corner. Nudge the stakes until the two numbers match.
- Tip For bigger layouts use 6-8-10 instead of 3-4-5: the bigger the triangle, the more exact the corner.
- Tip Batter boards (two stakes with a crosspiece set 2 ft outside each corner) let you take the strings down to dig and put them back in exactly the same place.
✓ Sides are 96″ and 72″ and the diagonals match within 1/2″. Spray marking paint along the strings, then pull the stakes you're about to dig around.
5Dig out the pad
Cut the sod inside the paint lines with a flat spade, in strips about a foot wide, and roll it up. Then dig the whole 96″ × 72″ area 2 1/2″ deep. That's the trench the border timbers sit in, so their tops end up 1″ above the lawn.
Now dig the inside, 3 1/2″ in from the lines, down to 5 1/2″ below the lawn. That leaves room for 6″ of gravel finishing 1/2″ below the timber tops.
Find the high corner: lay a straight 2×4 across the hole with a level on it. Dig the high side down to match the low side rather than filling the low side with loose dirt. Dug soil is firm; added soil sinks.
Rake out roots and big stones, then tamp the bottom with the hand tamper: lift it waist high and let it drop, overlapping each hit, until your boots don't leave prints.
- Tip On a slope steeper than about 1″ per foot the low side needs a second row of timbers. Use a flatter spot or ask a landscaper.
- Tip Keep the sod: it patches bare spots around the pad when you're done.
- Tip Don't dig or tamp soaking-wet or frozen ground: wet soil smears and never packs, frozen soil settles when it thaws. Wait for two dry days after heavy rain.
- Tip You'll move about 21 cubic feet of soil. A wheelbarrow holds about 3; decide where it goes before you start.
✓ The trench is 2 1/2″ deep, the inside 5 1/2″ deep, measured down from a string pulled tight across the lawn. The bottom is firm and level within about 1/2″ end to end, in both directions and on both diagonals.
6Set the border timbers
Lay the long timbers (A) along the long sides and the short ones (B) between them, inside the long ones.
At each corner, predrill and drive two 6″ timber screws through the long timber into the end of the short one.
Measure the diagonals and push the frame until they match. Then check level along every side; dig out under the high spots or pack soil under the low spots and tamp it.
Drill a 1/2″ hole straight down through each timber, about 1 ft from each end and every 4 ft between. Hammer a rebar stake through each hole until it's flush with the top: 8 stakes in all. They stop the frame creeping apart.
✓ Diagonals match within 1/2″. A level laid on each timber reads level, and on a straight 2×4 across the frame, both ways.
STOP. Wear gloves and a dust mask when cutting pressure-treated wood, and don't burn the offcuts.7Lay landscape fabric
Roll landscape fabric over the dirt inside the frame. Run it up the inside of the timbers a few inches. Overlap the strips by 12″ where they meet.
Pin it with a few garden staples, or just hold the corners down with the first shovels of gravel.
- Tip The fabric keeps the gravel from sinking into the mud over the years and slows weeds. It doesn't need to be perfect.
8Fill and compact the gravel in layers
You need about 1 cubic yards, delivered of crushed gravel. Ask for 3/4″ crushed stone (drains well) or dense-grade aggregate (crusher run, packs hardest). Not pea gravel: round stones roll and never lock together.
Spread a 2″ layer with a rake. Mist it with a hose so it's damp, not muddy. Damp gravel packs much better than dry.
Compact it: go over every inch with the hand tamper, overlapping, two or three passes. For a pad bigger than about 8′ × 8′, rent a plate compactor for half a day; it does in minutes what takes an hour by hand.
Repeat 2″ layers until the gravel is level with the top of the timbers: about 6″ in all.
Screed the top: rest a straight 2×4 on two opposite timbers and drag it across in a side-to-side sawing motion, filling low spots and pulling off the extra. Tamp once more.
The screed board (C) is the straight 84″ 2×4. Rest it on both long timbers and drag it toward you in a side-to-side sawing motion.
- Tip Compacting in thin layers is the whole trick. Six inches tamped at once only packs the top inch, and the rest settles later.
- Tip If the gravel was delivered, have it tipped on a tarp near the pad and wheel it in.
✓ Walking on it leaves no prints. A level on the straight 2×4 reads level in every direction.
9Finish around the edges and check it after rain
Shovel the leftover soil against the outside of the border timbers and tamp it, so the lawn meets the timbers with no gap a mower wheel could drop into.
Slope the soil away from the pad for the first 2–3 ft, about 1″ per foot, so rain runs off rather than toward it. Patch bare soil with the sod you rolled up and water it daily for two weeks.
Set the shed's skids or blocks straight onto the gravel. Check them with a level and add or scrape gravel to adjust. Never shim with wood: it rots.
After the first heavy rain, look at the pad: no puddles should sit on it. Top up any low spot with gravel, mist it and tamp it.
- Tip Every spring, rake the top inch and add a few bags where it has thinned. Pull weeds while they are small; the fabric stops most of them.
✓ An hour after a hard rain, no water stands on the gravel and none flows toward the pad from the lawn.
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.