10×8 ft lean-to garden shed plans

Parts

Cut list

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 and a straight edge (or have the store cut the sheets)
• Miter saw, or circular saw in two passes, for 4×4 posts
• Circular saw
• Framing hammer or nailer
• 4 ft level
• Chalk line
• Sledgehammer and scrap block
• Stepladders (two)
• Tin snips or metal-cutting blade
• Shovel, rake and hand tamper
• Wheelbarrow
• Sander, 120 and 180 grit

Underlined words have a short explanation: hover or tap them. All of them are on the glossary page.

1. 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.

2. 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. Cut sheets with the good face down when using a circular saw: the blade splinters the top face.

   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.

3. 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 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.

4. 4Mark out a square rectangle

   Hammer a stake at one corner of the gravel pad. Measure 144″ 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 120″ out along it.

   Measure the last corner from the other two (144″ and 120″) 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 144″ and 120″ and the diagonals match within 1/2″. Spray marking paint along the strings, then pull the stakes you're about to dig around.

5. 5Dig out the pad

   Cut the sod inside the paint lines with a flat spade and peel it off in strips. Then dig the whole area 1″ deep. The border timbers sit on the bottom, so the finished pad stands about 2 1/2″ above the lawn and rain runs off it.

   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 a 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.

   ✓ The bottom is firm and level within about 1/2″ end to end. Check in both directions and on both diagonals with the 2×4 and level.

6. 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: 10 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.

7. 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.

8. 8Fill and compact the gravel in layers

   You need about 1.75 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 4 1/2″ 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.

   • 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.

9. 9Set the skids

   Skids are the 3 ground-contact 4×4s the whole shed sits on. They spread its weight over the gravel and let air under the floor so it stays dry.

   Lay them across the pad running the long way (120″), centred on the pad so there is 12″ of gravel past the shed on every side. Space them 96″ outside to outside, with the third one centred between.

   Lay a level on each skid, and on a straight 2×4 across them. Scrape gravel away under high spots or add and tamp gravel under low ones.

   • Tip Never shim a skid with wood scraps or stones: they rot or roll and the floor sinks at that corner. Adjust the gravel instead.

   ✓ Every skid reads level along its length and they are level with each other. Their diagonals match.

10. 10Build the floor frame

    Sight along each 2×6 edge and find the crown (the slight hump). Mark it with an arrow: every joist goes crown up so the floor flattens under weight instead of dipping more.

    Stand the two rims (D) on edge on the front and back skids, 120″ long. Mark joist positions on both at once: the first flush with the end, then every 14 13/16″ on center, and the last flush with the far end.

    Set the 9 joists (E, 93″) between the rims on the marks and drive three 3″ galvanized nails through the rim into the end of each joist.

    Measure both diagonals of the frame and push the corners until they match. Then toenail every joist to each skid it crosses with two nails, one from each side.

    • Tip Nail through the rim with the joist held tight against your foot: the first nail always pushes it away a little.

    ✓ The frame is 120″ × 96″ and the diagonals match within 1/4″. The joist tops are flush with the rim tops.

11. 11Lay the floor

    The floor panels are tongue-and-groove plywood: one long edge has a tongue that slides into the groove of the next panel, so the joints don't sag between joists.

    Start at the front corner with the groove edge flush with the front rim. The long side runs across the joists. Every panel end must land on the middle of a joist; cut panels to make that happen.

    Tap each next panel's tongue into the groove with a sledge and a scrap block (never hit the tongue itself). Stagger the end joints between rows like bricks.

    Screw with 2 1/2″ screws every 6″ along the edges and every 12″ along each joist in the middle. Snap chalk lines over the joist centres first so the screws hit them.

    ✓ Panels are flush with the frame on every side, every screw is in a joist, and the floor doesn't flex underfoot.

12. 12Build and raise the back wall

    A wall is studs (vertical 2×4s) between a bottom plate and a doubled top plate. Build each wall flat on the floor, then stand it up.

    Lay out the back wall: cut its three plates, 120″ long. Hold a bottom plate and a top plate together, edges flush, and mark the stud positions across both at once with a speed square: the first flush with the end, then every 16″ on center (the tape measure's red marks), and the last flush with the far end. 9 studs, each 61 1/4″ long.

    Lay the plates on edge with the studs between them on the marks. Drive two 3″ nails through the plate into each stud end. Nail the second top plate on top of the first.

    Stand the wall up at the back edge of the floor, flush with the outside. Nail through the bottom plate into the rim and joists every 16″. Hold a level on the end stud: when it's plumb, brace the wall with a 2×4 screwed to the wall and to a block screwed to the floor.

    ✓ The wall is 65 3/4″ tall, plumb, and flush with the floor edge.

    STOP. Walls are heavy and catch the wind. Two people raise them, and every wall stays braced until the rafters are on.

13. 13Build and raise the front wall

    Lay out the front (door) wall: cut its three plates, 120″ long. Hold a bottom plate and a top plate together, edges flush, and mark the stud positions across both at once with a speed square: the first flush with the end, then every 16″ on center (the tape measure's red marks), and the last flush with the far end. 8 studs, each 83 1/2″ long.

    The door needs a framed hole, the rough opening, 36″ wide, centred. At each side a full-height king stud is nailed to a shorter jack stud (M, 78″). The header (N), two 2×6s nailed face to face, sits on the two jack studs and carries the roof over the gap.

    Nail it together flat, square it by matching the diagonals, then stand it up at the front edge of the floor, nail the bottom plate down and brace it plumb. Leave the bottom plate whole across the door for now: it keeps the wall stiff while you lift it. Cut it out flush with the jacks once the wall is up.

    • Tip Before cutting the bottom plate out of the doorway, set the circular saw blade to 1 1/2″ deep so it can't cut into the floor.

    ✓ The rough opening is 36″ wide and 79 1/2″ tall from the floor, the same width at the top and the bottom.

14. 14Build and fit the side walls

    Lay out the side walls: cut three plates for each, 89″ long. Hold a bottom plate and a top plate together, edges flush, and mark the stud positions across both at once with a speed square: the first flush with the end, then every 16″ on center (the tape measure's red marks), and the last flush with the far end. 7 studs per wall, each 61 1/4″ long.

    The side walls fit between the front and back walls, so their plates are 89″. They are the same height as the back wall.

    Stand each one in place, nail the bottom plate to the floor, and nail its end studs to the front and back walls' end studs with 3″ nails every 12″.

    Check every wall for plumb again and adjust the braces. Then nail the back wall's top plates to the side walls' top plates where they meet.

    ✓ All four walls are plumb, the corners are tight, and the diagonals across the top of the walls match.

15. 15Cut and set the rafters

    Rafters are the sloped boards that hold up the roof. This roof slopes 3 in 12: the roof rises 3″ for every 12″ it runs sideways, so rain runs off the low side. Each of the 6 rafters is a 2x6 114″ long.

    Sight down each rafter's edge to find its crown (the slight hump). Mark it with an arrow: every rafter goes crown up, so the roof's weight flattens it instead of making it sag more.

    Make a pattern rafter: lay one across the front and back walls where it will sit, with 8″ hanging past the high side and 6″ past the low side. That overhang keeps rain off the walls below. Mark both ends with a vertical line (a plumb cut) using a speed square set to 3 on its "common" scale.

    Where the rafter crosses each wall, mark a birdsmouth: a small notch whose flat seat sits on the top plate. Make the seat 1 1/2″ wide and never cut deeper than a third of the rafter's depth. Cut the notch with a circular saw, stopping at the corner, and finish with a handsaw so you don't over-cut.

    Test the pattern at both ends of the building and the middle. When it fits everywhere, use it to mark the rest, crown up each time.

    Set the rafters 24″ apart on center, the two end rafters flush with the outside of the frame. Fix each end with a hurricane tie (12 in all) using the short galvanized nails or screws named on the tie's package.

    • Tip Mark the rafter positions on both plates (or headers) with a tape and pencil before lifting any rafters, so you can set each one to its marks.
    • Tip If a rafter is badly twisted or cracked across, set it aside and use it for short blocks instead.

    ✓ Sight along the rafter tails from one end: they form a straight line. Measure the spacing at the top and the bottom; it matches.

    STOP. Lifting rafters overhead takes two people and stable ladders or a step platform. Don't climb on the walls.

16. 16Fill in under the end rafters

    The side walls stop at the back wall's height, so there is a sloped gap between each side wall and the end rafter above it: 22 1/16″ at the front, closing to nothing at the back.

    Stand a 2×4 on the side wall's top plate at each stud position, mark where it meets the underside of the end rafter, and cut it at that angle. Each one is a different length, so measure and cut them one at a time.

    Toenail each one to the plate with two nails and nail through the end rafter into its top. They give the siding something to nail to.

    ✓ Every infill stud is tight top and bottom, and the end rafter is straight, not bowed up or down.

17. 17Screw the purlins across the rafters

    Purlins are 2×4s laid flat across the rafters. The roof panels screw into them, so they need to be straight and in one flat plane. You have 6, each 124″ long.

    Set the lowest purlin flush with the low ends of the rafters and the highest flush with the high ends. Space the rest evenly between, about 22″ apart on center. Let each one stick out 2″ past the end rafters on both sides.

    At every rafter, drive two 3″ screws down through the purlin into the rafter. Stretch a string along the purlin first and screw it straight to the string, not to a wavy rafter edge.

    • Tip Put a purlin's crown (the slight bow along its edge) facing up the slope, and pick the straightest 2×4s for the lowest and highest rows: those are the edges people see.

    ✓ Lay a long straight board up the slope across the purlins at a few places: it touches every purlin, with no gaps over 1/8″.

18. 18Fasten the metal roof panels

    The roof is galvanized steel corrugated panels: wavy sheets 26″ wide. Each one laps over the next by one wave, so it covers 24″. You need 6 panel widths, each cut to 115 1/2″ long.

    Cut steel with tin snips, or a circular saw with a metal-cutting blade. Wear safety glasses, gloves and hearing protection; the saw throws hot sparks, so cut on bare ground away from dry grass.

    Lay a foam closure strip along the top of the lowest purlin and the highest purlin. Each panel sits on them, and they plug the gaps under the waves so wasps, birds and blown rain stay out.

    Start at the end of the roof away from the prevailing wind, so every lap faces downwind and rain isn't blown into it. Set the first panel 1″ past the end rafter's outside face and with its low end 1″ past the lowest purlin. That overhang is your drip edge: water drips off the panel, clear of the wood.

    Screw through the panel into each purlin with the sealing-washer roofing screws, following the screw pattern in the panel maker's instructions (usually beside every second wave on the middle purlins and every wave on the lowest and highest purlins). Put one screw through both panels at every lap on every purlin.

    Drive each screw straight and stop when the rubber washer just squashes flat. Loose screws leak; overtightened ones split the washer and dent the panel.

    Lay each next panel overlapping the last by one full wave. Before screwing it, measure from the panel edge to the end of the roof at the top and at the bottom; the two numbers must match, or the panels fan out across the roof.

    • Tip Practice the screw depth on an offcut screwed to a scrap of 2×4 before you start on the roof.
    • Tip Sweep the metal shavings off the panels the same day. Left there, they rust and leave orange streaks.

    ✓ The low edges form one straight line, every lap is a full wave, and every washer is snug but not bulging. Spray the roof with a hose and look underneath: no drips at the screws.

    STOP. Cut panel edges are as sharp as a knife: wear gloves the whole time. Never stand on the panels or the purlins between rafters; work from a ladder at the ends, or a plank laid across several rafters.

19. 19Side the walls

    T1-11 siding panels are grooved exterior plywood that act as the wall bracing and the outside finish in one sheet. Stand them vertically with the grooves up and down.

    Set the bottom edge flush with the bottom of the floor rim, so the siding laps over the floor frame and ties the walls to it. Panel edges must land on the middle of a stud. Nail every 6″ along the edges and every 12″ into the studs in between with the galvanized siding nails.

    Leave a 1/8″ gap between panels (a nail is a good spacer). The edge with the shiplap lip goes over the next panel's edge.

    On the front, sheath right over the door opening. Then drill a hole in each corner of the opening from inside and cut along the framing with a circular saw set just deeper than the siding, so the cut-out comes out in one piece: it becomes the door.

    On the sides, hold each panel in place, mark the roof slope along the end rafter from inside, take it down and cut to the line. The side panels run 97 7/8″ tall at the front, starting 3″ up from the bottom of the rim so one sheet reaches the roof.

    • Tip Paint or seal the bottom edge of every panel before nailing it up: that end grain sits closest to the ground and soaks up splash.

    ✓ All panel edges are on studs, the grooves are plumb, and the bottom edges form a straight line.

20. 20Build and hang the door

    Trim the cut-out to 35 1/2″ wide and 79″ tall, so there is a 1/8″ gap all round in the opening. If a panel seam ran through the opening, the cut-out came out in two pieces: lay them face down edge to edge and the rails join them.

    On the back of each leaf, screw three rails (U) across: top, middle and bottom, 1/2″ in from each side, with 1 1/4″ screws every 4″.

    Add the diagonal brace (V) between the bottom and middle rails: it starts at the bottom on the HINGE side and climbs toward the latch side. That way it holds up the latch corner, the corner that sags. Cut its ends to fit snug against the rails.

    Screw three strap hinges per leaf across the rails onto the wall framing beside the opening. Shim the leaf in the opening with 1/8″ spacers while you fix the hinges. Add the hasp.

    ✓ The door swings without rubbing, the gap is even all round and it closes flush with the siding.

21. 21Trim and caulk

    Corner trim covers the panel edges at each corner, where water would otherwise get in. Each corner gets two 1×4s: one on each face, the second overlapping the edge of the first.

    Nail with siding nails every 12″. Caulk the joint where the trim meets the siding, and every gap at the top of the walls.

    Prime and paint the siding and trim with exterior paint within a few weeks: bare T1-11 weathers grey and the grooves start to split.

    • Tip Staple insect screen over the gaps between rafters at the top of the walls: the airflow keeps the shed dry, and the screen keeps wasps out.

    ✓ No panel edge shows at any corner, and there are no gaps a pencil could poke into.

22. 22Anchor the shed to the ground

    A shed on skids is held down only by its own weight. A strong wind can slide or tip it. Ground anchors tie it down.

    At each corner, just outside the floor, twist an auger anchor into the ground: put a steel bar through its eye and walk it round until only the eye shows above the gravel. If you hit a rock, move 6″ and try again.

    Drill a hole through the end of the nearest skid as the kit shows, run the cable from the anchor eye through it, pull it tight and fix it with the clamps supplied.

    ✓ Every cable is tight; lifting hard on a corner doesn't raise it.

    STOP. Call 811 before you drive the anchors too, if you didn't mark this far out the first time: they go 30″ or more into the ground.

23. 23Finish

    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.