4×4 ft small concrete pad 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 or miter saw
• Flat spade and square shovel
• Steel garden rake
• Hand tamper
• Small sledgehammer
• 4′ level
• Wheelbarrow and a mortar hoe for mixing
• Magnesium hand float, 12–16″
• Concrete edger
• Concrete groover (jointing tool)
• Stiff push broom
• Bolt cutters (for the mesh)
• Waterproof gloves, rubber boots and safety glasses
• Bucket marked in quarts
• 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.

   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. 3Pick the pour day and line up help

   Concrete is the one part of this job you can't pause. From the moment water hits a batch you have about 30–45 minutes to get it in place, then roughly 1–3 hours to finish the surface. Plan the 48″ × 48″ pad for a day you can give to it completely.

   Check the forecast. You want 50–80°F (10–27°C), no rain for at least 12 hours after you finish, and nothing below 40°F (5°C) for the next 2 days and nights. Rain on fresh concrete washes the paste off the top and leaves it pitted and weak; water that freezes inside it cracks it from within.

   Hot (over 85°F), sunny or windy days make concrete stiffen about twice as fast. On those days start at first light, keep the bags in the shade, and mist the gravel or mold before you pour so it doesn't suck the water out of the mix.

   10 bags of 80 lb mix is 800 lb. A car carries about 10 bags safely and a half-ton pickup about 20; past that, pay for delivery. Stack them on a pallet or boards off the ground and cover them: a bag that gets damp turns to rock.

   Plan two days: day 1 dig, gravel and forms; day 2 a morning pour. The pad is 16 sq ft, 4″ thick: 5.3 cu ft of concrete.

   • Tip Lay everything out the evening before: bags, wheelbarrow, hoe, shovel, float, edger, a bucket of water for rinsing tools, a hose, and plastic sheeting in case of a surprise shower.
   • Tip Concrete waits for no one, so don't start in the afternoon. A morning start leaves daylight for finishing.

   ✓ The forecast is dry for 12+ hours after the pour and above 40°F for 2 days. Every bag, tool and helper is on site before you open the first bag.

4. 4Call 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 concrete 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.

5. 5Mark out a square rectangle

   Hammer a stake at one corner of the pad. Measure 48″ 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 48″ out along it.

   Measure the last corner from the other two (48″ and 48″) 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 48″ and 48″ and the diagonals match within 1/2″. Spray marking paint along the strings, then pull the stakes you're about to dig around.

6. 6Dig out and tamp the ground

   Spray a second line 6″ outside the strings all round. Dig everything inside it: 60″ × 60″. The extra 6″ gives the forms and stakes firm ground and puts gravel under the slab's edges, where it cracks first.

   Dig 7″ below the lawn: 4″ for gravel plus 4″ for concrete, less 1″ because the finished pad stands 1″ above the lawn so rain runs off it.

   Measure down from a string pulled tight across the hole, every couple of feet. Scrape high spots down; don't fill low spots with loose soil, which sinks. Fill them with gravel later instead.

   Tamp the bottom with the hand tamper: lift it waist high, let it drop, overlap every hit, until your boots leave no prints.

   • Tip Don't dig or pour on soaking-wet or frozen ground. Wet soil won't pack and frozen soil settles when it thaws, cracking the slab.
   • Tip Keep the sod: it patches the bare strip around the finished pad.

   ✓ The hole is 7″ deep everywhere (within 1/2″), flat, firm, and has no roots, sod or soft spots.

7. 7Spread and compact 4″ of gravel

   Spread crushed gravel (crusher run or 3/4″ crushed stone) in two layers of 2″. You need about 10 cu ft loose.

   Rake each layer flat, mist it with the hose until it's damp but not muddy, then tamp every inch twice, overlapping. Damp gravel packs; dry gravel just shuffles around.

   When the second layer is done, the gravel top should be 3″ below the lawn: exactly 4″ below where the finished pad will be.

   • Tip Compacting in thin layers is the whole trick. A thick layer tamped at once packs only on top and settles later, and the slab cracks over the soft spot.

   ✓ Walking on it leaves no prints and a dropped tamper bounces rather than sinking. A straight 2×4 laid on it rocks on no high spots.

8. 8Build and set the forms

   Stand the long form boards (A) on edge along the long strings, inside faces exactly on the line, and the short boards (B) between them. Screw each corner with two 3″ screws through the long board into the end of the short one.

   Hammer a stake (C) against the outside of the forms at every corner and every 36″ between: 12 in all. Drive them about 12″ into the ground with a small sledgehammer. Then screw through each stake into the form with two 3″ screws.

   Set the height: the tops of the forms are the top of the finished pad. Set the high side 1″ above the lawn and level along its length. Set the other long side 1/2″ lower (1/8″ per foot across the 48″ width) so water runs off; slope it away from the house or toward the lawn.

   Raise a low form by tapping its stake up and re-screwing; lower it by hammering the stake down. Then tap or saw every stake top so it sits 1/2″ below the form top, or the screed will catch on it.

   A 2×4 is only 3 1/2″ tall, so the gravel inside sits 1/2″ below the bottom of the boards. Bank gravel or soil against the outside of the forms so wet concrete can't squeeze out underneath.

   Spray form release oil on the inside faces so they pull off cleanly later.

   • Tip Where the pad will touch a wall, step or existing slab, glue a 1/2″ foam isolation strip against it first, top flush with the forms. Never pin or dowel the pad to the house.
   • Tip Lay a level on a long straight board across the forms before every screw goes in; adjusting after is twice the work.

   ✓ Diagonals inside the forms match within 1/4″. The forms measure 48″ × 48″ inside. A level on each long form reads level along its length, and on a straight board across them it shows the 1/2″ drop. Push hard on a form: it doesn't move.

   STOP. Forms must be stiff. Wet concrete weighs about 145 lb per cubic foot and a bulging form can't be fixed mid-pour. Add a stake anywhere a board flexes.

9. 9Lay the wire mesh on chairs

   Unroll or lay out 2 sheets of wire mesh. Cut them with bolt cutters so the mesh stops 2″ short of the forms all round: 44″ × 44″.

   Overlap sheets by one full square (6″) and tie the overlaps with tie wire every 12″, twisting the wire tight with pliers.

   Set the mesh on 4 plastic mesh chairs, about one every 2 ft each way. The chairs hold it 2″ up, in the middle of the 4″ slab: mesh lying on the gravel does nothing.

   Flatten any curl by stepping on it and bending it back, so no end sticks up above the forms.

   ✓ The mesh sits about 2″ off the gravel everywhere, 2″ in from every form, with no wire poking above the form tops.

   STOP. Cut mesh ends are sharp and springy. Wear gloves and safety glasses while cutting and placing it.

10. 10Mix the concrete

    You'll use 10 bags of 80 lb concrete mix for the 48″ × 48″ pad. Mix one or two bags at a time in a wheelbarrow: concrete starts to stiffen in about 30–45 minutes (faster on a hot day), so only mix what you can place right away.

    Pour about 2 quarts of clean water into the wheelbarrow first, then empty one bag on top. (Each 80 lb bag needs about 3 quarts in total.)

    Mix with a hoe or square shovel: pull the dry powder from the corners and bottom into the wet middle and chop through it. Keep going until there are no dry pockets.

    Add the last of the water a cup at a time, mixing between each.

    Get the thickness right. It should look and feel like thick oatmeal or stiff peanut butter. A hoe dragged through leaves ridges that stand up, and a handful squeezed in a gloved hand holds its shape. Too dry: it crumbles and won't stick together, so add a little water. Too wet: it flows flat, water pools on top, and the concrete will be weak and crack. Then add some dry mix from a spare bag.

    Mix two bags per batch: 5 batches in all. Have one person mixing the next batch while another places the last one.

    • Tip More water makes concrete easier to push around and much weaker. Resist the urge.
    • Tip Rinse the wheelbarrow, hoe and shovel before the concrete sets on them. Don't wash concrete into drains or onto the lawn: let leftovers harden in a scrap box and throw them out.
    • Tip Buy one more bag than you need. Running out halfway through a pour is the most common mistake.
    • Tip Every batch should be the same stiffness. Measure the water in a marked bucket instead of using the hose freely.

    ✓ Even grey colour throughout, no dry powder, no puddles of water on top; a ridge made with the hoe stands up.

    STOP. Wet concrete is caustic and burns skin. Wear waterproof gloves, safety glasses, long sleeves and long pants. Open bags slowly and wear a dust mask: the dust has silica. Rinse any concrete off your skin right away.

11. 11Pour and screed

    Mist the gravel with the hose just before the first batch so it's damp, with no puddles.

    Start at the far corner. Dump each batch right where it's needed, against the last one, a little higher than the forms. Move it with a hoe or square shovel, pushing and pulling. Don't drag it far with a rake: that separates the stones from the paste.

    As each section fills, jab the concrete next to the forms with the shovel and tap the outside of the forms with a hammer all round. This settles it into the corners and removes air pockets that would leave holes on the edges.

    Place each new batch within 20–30 minutes of the last, so they knit together. Concrete laid against a batch that has already stiffened leaves a weak line called a cold joint.

    Screed as you go: two people, one at each end of the screed board (D), rest it on the long forms and pull it toward the empty end in a side-to-side sawing motion. Shovel concrete into any low spot ahead of the board and screed again. Two passes per section.

    • Tip As you pour, reach in with a rake or hook and lift any mesh that got pushed down back to the middle of the slab.
    • Tip Keep the screed board moving steadily. A pile of concrete in front of it means low ground ahead; a gap behind it means the slab is low there.

    ✓ The concrete is flat and flush with the form tops everywhere, with no low spots that hold water when you trickle a little on.

    STOP. Don't pour in rain or with rain forecast in the next 12 hours, or below 40°F (5°C). Keep wet concrete off skin; kneel only on a board, never on the concrete.

12. 12Float it, then wait for the bleed water

    Right after screeding, sweep the magnesium float over the whole surface in long, overlapping arcs. Keep the leading edge tilted up slightly so it glides instead of digging in. This presses the stones down and brings smooth paste up. Two passes is enough; overworking pulls water up and weakens the top.

    Now stop. Within minutes a shiny film of water rises to the top: that's bleed water. Do nothing to the surface while it is there. Finishing while it's wet works it back in and leaves a weak, dusty top that flakes off in a year or two.

    Expect to wait 30–90 minutes on a 70°F day, 2 hours or more on a cool day, and as little as 15–30 minutes on a hot, windy one. Rinse your tools while you wait.

    It's ready when the shine is gone and the thumbprint test leaves a print about 1/4″ deep with no water in it.

    • Tip If one corner dries much faster (sun on it), start finishing there first.

    ✓ No shine anywhere on the surface; a thumb press leaves a 1/4″ print that stays dry.

13. 13Edge and cut the control joints

    Run the edger along the inside of every form, its lip down against the form, leading edge tilted up. Push it back and forth in 2–3 passes until the edge is a smooth rounded lip. Rounded edges don't chip.

    At 48″ × 48″ the pad is small enough to need no control joint. Run the edger round it and move on.

    Make each joint in one steady pass from form to form, then go back over it once lightly to smooth the lips.

    • Tip Concrete always cracks somewhere as it shrinks. A control joint is a weak line you choose, so the crack hides in the groove instead of wandering across the middle.

    ✓ A rounded edge runs all the way round the pad with no ragged spots.

14. 14Final float and broom finish

    Float the surface once more, lightly, to close any marks left by the edger and groover. Then re-run the edger and groover once to clean up their lines.

    Dampen a stiff push broom and shake it out. Starting at the far side, pull it toward you in one long stroke from form to form, with light pressure. Lift it, step over, and pull the next stroke slightly overlapping the last. Run the lines across the direction people will walk.

    Don't go back over a stroke. If the broom tears the surface or leaves grooves deeper than 1/16″, wait 10 minutes and try again.

    • Tip A broom finish grips when wet. A smooth steel-trowelled finish looks nice indoors but is slippery outside, so don't trowel it glassy.

    ✓ An even, fine texture from edge to edge with the lines all running the same way, and crisp edges and joints.

15. 15Let the concrete cure

    Concrete hardens by reacting with water, not by drying out, so keep the 48″ × 48″ pad damp for the first 7 days: mist it with a hose morning and evening, or cover it with plastic sheeting held down at the edges.

    Keep it from freezing for the first week. Don't pour when it's below 40°F (5°C) or frost is forecast in the next two days. On hot days, pour in the early morning and shade it.

    You can walk on it or remove braces after 1–2 days. Wait 7 days before putting real weight on it. It reaches full strength in about 4 weeks.

    ✓ The surface is hard and grey-white when dry, with no powder when you rub it.

16. 16Strip the forms and backfill

    After 24–48 hours (48 if the nights were cool), back the screws out of the stakes, pull the stakes with a pry bar, and tap the form boards away from the slab with a hammer. Don't pry against the concrete edge: it's still weak.

    Fill the gap around the pad with soil, tamp it, and patch it with the sod you kept. Slope the soil away from the pad.

    You can walk on the pad after 24 hours. Wait 3 days for bins and furniture, 7 days for anything heavy, and never drive on it: it's a pad, not a driveway.

    • Tip Hairline cracks in the control joints are the joints working. A crack across a panel wider than a credit card is worth watching.

    ✓ The edges are crisp and unchipped, the pad sits about 1″ above the lawn, and water poured on it runs off the low side.

17. 17Finish

    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.

    Paint, stain or a clear coat (water-based polyurethane is the easiest). Apply thin coats with the grain, let each dry fully, and sand lightly with 220 grit between coats.

    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.