Shed Spare Room — Build Implementation Plan

For the builder (you): This plan is written task-by-task. Each task lists materials, tools, exact steps, and a verification checkpoint. Tick boxes as you complete them. Take a photo after each verification — this is your "commit." If a step doesn't make sense or seems wrong when you're standing in the shed with the tool in your hand, stop and ask rather than guessing.

Goal: Build a 6700 × 3780 mm insulated, lined, finished spare room inside the existing shed at Mittagong, suitable for use as a home office, guest bedroom, and chill space.

Approach: Hybrid room-in-a-room — three new freestanding stud walls (front, left, right) plus one shared back wall reusing the shed's existing wall and windows. Raised insulated timber subfloor with vinyl plank. New insulated flat ceiling at 2370 mm AFL. Owner-built carpentry, licensed electrician for all wiring, Scandinavian warm-modern aesthetic.

Reference spec: docs/superpowers/specs/2026-04-07-shed-spare-room-design.md — read this before starting any phase.

Total budget: ~$14,100 AUD (construction $9,600 + furniture $4,500)

Estimated owner labour: 60–90 hours, spread over 4–8 weekends depending on pace.

Build Phase Overview (the big picture)

Phase 0: Preparation, Measurement, and Procurement

Goal: Know exactly what you're building, in exactly what space, with exactly which materials on hand before you swing a hammer.

Task 0.1: Verify the shed measurements

• [ ] Step 1: Buy or borrow a quality 8 m tape measure and a 600 mm spirit level.
• [ ] Step 2: Clear the build zone in the shed enough to access all four corners.
• [ ] Step 3: Measure the actual interior shed dimensions in the build zone:
• Width along back wall (between side walls): _____ mm
• Depth from back wall to opposite point: _____ mm
• Height from slab to underside of lowest roof beam at the build location: _____ mm
• Height from slab to apex: _____ mm
• [ ] Step 4: Measure the two existing back-wall windows:
• Window 1: width _ mm, height mm, sill height from slab __ mm
• Window 2: width _ mm, height mm, sill height from slab __ mm
• Distance between windows: _____ mm
• Distance from window edges to side walls: _____ mm
• [ ] Step 5: Check slab condition. Any cracks > 5 mm? Any obvious damp patches? Slope toward door? Note anything weird.
• [ ] Step 6: Fire egress check: Verify each window can serve as an emergency escape route. Open each window fully and measure the clear opening (the unobstructed space you could climb through). Minimum required: 850 mm high × 600 mm wide clear opening, with the sill no higher than 1500 mm above finished floor level. If either window fails, stop and message me — we may need to modify the window or add a second exit.
• [ ] Step 7: Photograph all four corners of the build zone, the windows, and the slab condition. Save in the project folder.
• [ ] Verification: Compare to spec — if shed width is less than 7000 mm, the room needs to shrink. If less than 6900 mm, stop and message me before continuing — we'll need to adjust the layout.

Task 0.2: Confirm shed structure for fixings

• [ ] Step 1: Identify the shed's structural members:
• Are the columns C-section steel (Cee), Z-section, or open box?
• What's the column spacing on the back wall? (typically 1200, 1500, or 1800 mm)
• What's the girt spacing on the back wall? (horizontal members; typically 600–900 mm)
• [ ] Step 2: Check what you can fix into. Steel structure → you'll need self-drilling Tek screws (zinc, 14g × 25 mm minimum). Timber subframe → standard wood screws.
• [ ] Step 3: Photograph the back wall structure clearly so you have a reference when ordering battens and screws.

Task 0.3: Source the licensed electrician

• [ ] Step 1: Get 2 quotes from local Mittagong/Bowral electricians. Tell them: "I'm fitting out a room inside my shed, off the books, ~25 m². I need a rough-in walkthrough, then rough-in (1 day), then fit-off (half day). Power and lighting circuits, smoke alarm, ceiling fan blocking guidance. Likely from existing shed sub-board."
• [ ] Step 2: Confirm the sparky is OK working on a non-DA project. Most are; some refuse. Ask upfront.
• [ ] Step 3: Book a walkthrough date. Don't book the rough-in day yet — wait until framing is up. The walkthrough should happen now so they can advise on circuit feasibility before you build.
• [ ] Step 4: Sub-board capacity check: During the walkthrough, ask the sparky to verify the existing shed sub-board can handle the total load. Expected draw: 2000 W oil heater (~8.7 A) + 4 downlights + ceiling fan + 2 sconces + 8 double GPOs for general use. If the sub-board or the supply cable from the house can't handle it, the sparky needs to quote for an upgrade or a dedicated circuit from the house board.
• [ ] Step 5: Estimated cost: $2,000–2,800 total. Confirm fixed quote vs hourly.
• [ ] Verification: Walkthrough booked, sparky has seen the spec, sub-board capacity confirmed or upgrade quoted.

Task 0.4: Materials list — generate the BOM

This is the master list. Order in 3 batches: framing+floor, lining+insulation, finishes+fittings. Each batch has its own task below.

• [ ] Step 1: Print or save the BOM table (next task) so you have it on your phone when shopping.
• [ ] Step 2: Identify the 2 closest building suppliers (Bunnings Bowral, Mittagong Mitre 10, local timber yard). Note opening hours.
• [ ] Step 3: Verify your vehicle can transport: 6 m timber lengths (most can with the back seats down + a flag), 2400 × 1200 plasterboard sheets (almost no car — arrange delivery), 15 mm ply sheets (delivery).

Task 0.5: Bill of Materials — Phase 1 (Framing + Subfloor)

Order this batch first. Take delivery before Phase 2 starts.

Timber (all MGP10 pine unless noted):

Fixings:

Subfloor protection:

Subtotal Phase 1: ~$1,990

• [ ] Step 1: Place the order with your timber supplier. Confirm delivery date.
• [ ] Step 2: Pick up fixings from Bunnings on the same day or before delivery.
• [ ] Step 3: When delivery arrives, count every item against the BOM before signing. Suppliers regularly miss items.
• [ ] Step 4: Stack timber off the slab on bearers (use offcuts of any timber) inside the shed to keep it dry and straight.

Task 0.6: Tools required — verify you have or can borrow

• [ ] Step 1: Check the toolkit. You need:

• [ ] Step 2: Anything missing → buy or borrow now. Don't start Phase 1 with missing tools.

Task 0.7: Communicate with household

• [ ] Step 1: Tell anyone who shares the property what's happening, when, and how loud it'll be (intermittently loud — circular saw, hammer drill).
• [ ] Step 2: Identify a clean indoor area to take materials/tools you don't want left in the shed overnight.

Phase 0 verification: Measurements logged, sparky walkthrough booked, materials ordered, tools confirmed, household briefed. Take a "before" photo of the shed build zone — empty slab, looking from the front wall location toward the back windows.

Phase 1: Site Prep & Set-Out

Goal: Empty, clean slab with the room outline marked in chalk so you can see exactly where every wall is going.

Task 1.1: Clear the build zone

• [ ] Step 1: Move everything currently in the build zone to elsewhere in the shed or outside under cover. Allow yourself 1 m of working space beyond the room footprint on every side.
• [ ] Step 2: Sweep the slab clean with a stiff broom.
• [ ] Step 3: Inspect the slab one more time. Note any cracks > 5 mm — they get patched in Task 2.1.

Task 1.2: Establish reference lines

• [ ] Step 1: Decide which wall of the shed is your "back wall" (the one with the windows). Stand facing it.

• [ ] Step 2: The back wall is shared — your new battens fix directly to the shed back wall girts, no air gap. Mark the chalk line for the inside face of the new back wall lining at 120 mm out from the shed back wall (battens 50 + batts 50 + vapour 0.2 + plasterboard 10 + tolerance ~10). The side walls get a 50 mm air gap from the shed side walls — see Step 5.

• [ ] Step 3: Mark this line on the slab in chalk, full width of the build zone.

• [ ] Step 4: From this back-wall reference line, measure forward 3780 mm and snap a parallel chalk line — this is the inside face of the front wall.
• [ ] Step 5: Decide which side of the build zone is the "left wall." Measure 50 mm in from the shed left side wall (this is the air gap), then a further 100 mm in for the wall buildup → mark a chalk line 150 mm from the shed left wall, parallel to it. This is the inside face of the left wall.
• [ ] Step 6: Measure 6700 mm across from the left-wall reference line and mark the right-wall reference line, parallel.

• [ ] Step 7: Check diagonals: corner-to-corner measurements should be equal (within 5 mm). If not, the room is not square — adjust until they match.

• [ ] Verification: Stand inside your chalk lines. Does it feel like the right size? Lay a queen-bed-sized rectangle of chalk (1500 × 2000) where the bed will go. Does it feel right? Photo from each corner.

Task 1.3: Mark wall plate centrelines

• [ ] Step 1: From each "inside face" chalk line, mark a second parallel line 100 mm outward — this is where the outer face of the wall framing (and the bottom plate) will sit.
• [ ] Step 2: Mark stud positions on each wall along the bottom plate line, at 450 mm centres starting from one end. Mark with a small chalk cross.
• [ ] Step 3: Mark the door opening: the door is on the front wall, hinged on the right side (right when facing into the room from outside). Door rough opening = 870 mm wide × 2070 mm tall (820 leaf + 50 jamb allowance). Mark this on the front wall bottom-plate chalk line.

Phase 1 verification: All four wall lines snapped, square confirmed, stud positions marked, door opening marked. Photo of the chalk-marked slab from above (stand on a ladder).

Phase 2: Subfloor (Bearers, Batts, Ply)

Goal: A flat, insulated, level timber floor over the slab, ready to receive vinyl plank later.

Task 2.1: Patch the slab

• [ ] Step 1: Buy a 5 kg bag of concrete repair mortar (Sika or similar) if you noted any cracks in Phase 0. ~$25.
• [ ] Step 2: Mix per packet instructions (small batches).
• [ ] Step 3: Trowel into cracks, smooth flush with the slab. Cure 24 hours minimum before continuing.

Task 2.2: Install damp-proof membrane

• [ ] Step 1: Roll out 200 µm builder's plastic across the room footprint, extending 100 mm up each wall surface (shed back wall, and 100 mm beyond your side and front wall reference lines).
• [ ] Step 2: Overlap any joins by 200 mm minimum, tape with cloth duct tape.
• [ ] Step 3: Tuck the plastic up against the shed back wall and tape it temporarily so it stays vertical.
• [ ] Verification: No tears, no gaps, full coverage. Photo.

Task 2.3: Lay the bearers/joists

The joists run across the short axis (3780 mm direction), spaced at 450 mm centres along the 6700 mm long axis. 70 × 45 on edge gives a 70 mm tall cavity for batts. You need 16 joists (6700 / 450 = ~15 spaces + 1).

• [ ] Step 1: Cut sixteen 70 × 45 mm joists to 3780 mm length (the room's short dimension).
• [ ] Step 2: Cut 50 × 6 mm closed-cell foam pad strip into ~80 mm pieces. You'll need ~5 per joist (one every 800 mm).
• [ ] Step 3: Lay the first joist on its edge against one side wall reference line, on top of the DPM. Slip foam pad pieces between the joist and the slab at ~800 mm intervals so the joist never touches the slab directly.
• [ ] Step 4: Lay the next joist 450 mm away (centre-to-centre), parallel. Continue until all 16 joists are laid.
• [ ] Step 5: Check each joist is level along its length and across to its neighbours using a 1200 mm spirit level. Shim with extra foam pad pieces if any joist sags below the others.
• [ ] Step 6: Lateral restraint: The floor floats on the foam pads, but it must not slide on the DPM. Fix 75 × 75 mm galvanised angle brackets to the slab using Ramset nails (one leg down into the slab) at 8 locations around the perimeter — 2 per side, roughly at quarter-points. Screw the other leg of each bracket into the nearest perimeter joist with a 50 mm bugle screw. This pins the floor raft in position without rigidly coupling it to the slab.
• [ ] Step 7: The floor otherwise floats freely on the foam pads. The plywood deck above will tie all joists together into a rigid floating raft.
• [ ] Verification: All joists level within 3 mm across the whole floor. Lay your spirit level across multiple joists at random spots and check. Push the floor sideways — it should not slide.

Task 2.4: Insulate between the joists

• [ ] Step 1: Buy R2.0 polyester batts sized to fit the 450 mm joist spacing (typical batt: 430 × 1160 mm, fits 450 ctrs). Quantity: 25 m² of room → ~30 batts.
• [ ] Step 2: Wear long sleeves, gloves, dust mask, eye protection. Polyester batts are itchy.
• [ ] Step 3: Friction-fit batts into each joist cavity, full height (70 mm). No gaps. Cut batts to length around end joists with a sharp Stanley knife on a board.
• [ ] Verification: Every cavity full, no gaps, no batts crushed below the joist top edge (they should be flush with the joist top, not bulging or recessed).

Task 2.5: Lay the ply subfloor

• [ ] Step 1: Plan the ply layout: 2400 × 1200 sheets laid with the long dimension across the joists. Stagger joints so no two sheets line up end-to-end across multiple rows (running bond pattern).
• [ ] Step 2: Measure the room: 6700 × 3780 = ~25.3 m². Each sheet is 2.88 m². You need 25.3 / 2.88 = 8.8 sheets. Buy 9 sheets to allow waste. (Already in BOM.)
• [ ] Step 3: Apply construction adhesive bead along every joist top before placing each sheet.
• [ ] Step 4: Lay the first sheet flush against the back wall reference, against one corner. Screw down with 50 mm bugle screws into every joist underneath, at 200 mm spacing along each joist.
• [ ] Step 5: Continue laying sheets, butting tight, staggering joints.
• [ ] Step 6: At the perimeter, leave a 5 mm expansion gap to the wall reference lines (vinyl plank manufacturer's recommendation).
• [ ] Step 7: Cut sheets at the door opening, around any obstructions, with a circular saw and a straightedge.
• [ ] Verification: Walk on the entire deck. Listen and feel: any squeaks, sponginess, or movement = a missed glue point or loose screw. Fix immediately. The floor should feel rock solid.

Task 2.6: Protect the deck

• [ ] Step 1: Cover the ply with a layer of cardboard or builders' paper to protect it from boot scuffs, dropped tools, and paint splatter during the rest of the build. Do not lay vinyl yet.

Phase 2 verification: Subfloor is complete, level, insulated, protected. Photo from each corner.

Phase 3: Wall Framing

Goal: Three new freestanding stud walls (front, left, right) framed and standing, plumb and square.

Task 3.1: Cut the bottom plates

• [ ] Step 1: Cut a 90 × 45 mm pine bottom plate to length for each wall:
• Front wall: 6700 mm long (less the door rough opening, but cut full first and notch later)
• Left wall: 3780 mm long − 90 mm front wall thickness = 3690 mm
• Right wall: 3690 mm
• [ ] Step 2: Lay each plate flat on the subfloor, aligned with its chalk line.

Task 3.2: Cut and mark the top plates

• [ ] Step 1: Cut a top plate for each wall, same length as its bottom plate.
• [ ] Step 2: Lay each top plate next to its corresponding bottom plate.
• [ ] Step 3: Mark stud positions on both plates simultaneously: starting from one end, mark every 450 mm. Use a square to transfer the mark across the plate width.
• [ ] Step 4: At the door opening (front wall), mark king studs flanking the rough opening (870 mm wide), then jack studs inside the king studs supporting the lintel header.

Task 3.3: Cut the studs

Important sequencing note: Final stud length depends on knowing the exact height from subfloor to the underside of the ceiling joists, which aren't installed until Phase 4. However, the ceiling joists sit on top of the wall top plates, so the stud length is actually independent of joist depth — it's determined by desired ceiling height minus top plate (90 mm) minus bottom plate (90 mm). Target: 2370 mm ceiling AFL − 90 mm bottom plate − 90 mm top plate = 2190 mm stud length. Verify this calculation in the shed: measure from the ply subfloor to the height where you want the underside of the ceiling joists (2370 mm), subtract 180 mm for the two plates.

• [ ] Step 1: Calculate and confirm stud length as above. Cut a test stud first, assemble a short section of bottom plate + stud + top plate, stand it on the subfloor, and measure the top-plate height. It should land at 2370 mm. Adjust if needed before cutting the rest.

• [ ] Step 2: Cut the studs:

• Front wall: 6700 / 450 = ~15 spaces = ~16 studs (subtract 2 in the door opening, add jack studs and king studs) ≈ 16 studs total
• Left wall: 3690 / 450 ≈ 9 studs
• Right wall: 3690 / 450 ≈ 9 studs
• Total: ~34 studs at 2190 mm each
• [ ] Step 3: Stack the cut studs near each wall they belong to.

Task 3.4: Frame walls flat on the subfloor

You'll build each wall as a complete assembly (bottom plate + studs + top plate + noggins) flat on the deck, then stand it up and fix it in place. This is standard platform framing.

• [ ] Step 1: LEFT WALL FIRST (the easiest practice run).
• Lay the bottom plate and top plate parallel, stud-length apart.
• Place a stud between them at each marked position. Square each stud to the plate using your carpenter's square.
• Drive 2 × 75 mm bugle screws through the plate into the end of each stud (top and bottom).
• [ ] Step 2: Check the wall is square: measure the diagonals. Equal = square. If not, rack one corner until they match.
• [ ] Step 3: Add a row of noggins (horizontal blocking) at mid-height (1150 mm from bottom plate) between every stud. Cut 90 × 45 to fit between studs (typically 410 mm). Screw through stud face into noggin end.
• [ ] Step 4: Move the assembled wall onto its chalk line. Apply a continuous bead of construction adhesive under the bottom plate. Screw the bottom plate to the subfloor with 75 mm bugles every 400 mm. The screws hit ply only — the ply is the diaphragm.
• [ ] Step 5: Plumb the wall using your spirit level on the studs. Adjust until perfectly vertical. Temporarily brace with a diagonal to the subfloor or a fixed point — have someone help.
• [ ] Step 6: RIGHT WALL — repeat steps 1–5.
• [ ] Step 7: FRONT WALL — repeat steps 1–5, including the door opening:
• Frame the door opening: king studs each side at 870 mm apart. Jack studs (shorter, supporting the lintel) inside the king studs. Lintel = 90 × 90 timber across the top of the door rough opening at 2070 mm AFL. Cripple stud above the lintel up to the top plate.
• [ ] Verification: All three walls standing, plumb, on their chalk lines, bottom plates fixed. Adhesive squeezing out slightly along plate edges. Walls are not yet tied together at the corners. Photo of all three walls standing.

Task 3.5: Tie the walls together at the corners

• [ ] Step 1: At each corner where walls meet (front-left, front-right), screw the end stud of one wall through the face of the end stud of the perpendicular wall, using 100 × 4 mm bugle screws every 600 mm.
• [ ] Step 2: This locks the walls into a rigid box.
• [ ] Step 3: Re-check plumb on every wall. Adjust if needed.

Task 3.6: Add the second top plate

• [ ] Step 1: Cut a second top plate for each wall, same length, lapping at the corners (so the second top plate of the front wall extends over the top plates of the side walls, locking them together).
• [ ] Step 2: Screw down with 100 × 4 mm bugles every 400 mm.
• [ ] Verification: Walls feel rigid when you push on them. Diagonals across the room (corner of front-left to corner of back-right) are within 5 mm of each other.

Phase 3 verification: Three walls framed, plumb, square, tied together at corners with double top plate. Door opening framed correctly. Photo from each corner of the room interior.

Phase 4: Back Wall Battens & Ceiling Joists

Goal: Battens fixed to the existing shed back wall ready for insulation and lining; new ceiling joists installed at 2370 mm finished height.

Task 4.1: Install back-wall battens

Condensation risk: The shed's metal back wall will be the cold surface where moisture condenses. The vapour control layer (Phase 8) is the primary defence, but any VCL failure traps moisture with no drying path. To mitigate this, leave a small ventilated air gap at the top and bottom of the batten cavity so any moisture that does get through can dry by convection into the shed roof space.

• [ ] Step 1: Mark vertical lines on the shed back wall at 450 mm centres across the room width. Use a chalk line.
• [ ] Step 2: Cut 50 × 35 mm pine battens to length: each from 50 mm above finished floor level to ceiling joist height (leave a 50 mm gap at the bottom). You'll trim to actual ceiling joist height once installed.
• [ ] Step 3: Fix each batten to the shed back wall structure using self-drilling 14g × 25 mm Tek screws into the shed girts. Aim to hit at least 3 girts per batten (top, middle, bottom). Drive screws flush.
• [ ] Step 4: At each existing window opening, batten around the window frame, not over it. Battens go up to the window frame edge, then a horizontal batten under the sill and over the head.
• [ ] Step 5: Ventilated cavity: At the top of the back wall (above the ceiling line, behind the ceiling joists), leave the batten cavity open to the shed roof space — do NOT seal or block the top. At the bottom, the 50 mm gap between batten ends and the floor allows air entry. This creates a slow convection path: any moisture behind the VCL can dry upward into the shed roof space rather than being trapped.
• [ ] Verification: All battens plumb, secure (push hard — they shouldn't move), no batten covers a window. Top of cavity open to shed roof space, bottom gap visible. Photo.

Task 4.2: Frame the ceiling joists

The ceiling joists span the short axis (3780 mm, front wall to back wall) using 190 × 45 mm timber on edge. This gives a safe span with no mid-span support needed, and the 190 mm cavity depth properly accommodates R4.0 ceiling insulation without compression.

• [ ] Step 1: Cut 15 ceiling joists (190 × 45 on edge) to 3780 mm length — snug between the front wall top plate and the back wall ledger. Verify your actual measurement.
• [ ] Step 2: Install a horizontal ledger (90 × 45 mm) across the top of the back wall battens at ceiling height (2370 mm AFL). Fix to each batten with 75 mm bugle screws. This supports the back end of each ceiling joist.
• [ ] Step 3: Mark joist positions on the front wall top plate and the back wall ledger at 450 mm centres along the 6700 mm width → 15 joists.
• [ ] Step 4: For each joist:
• Use galvanised joist hangers (190 × 45) screwed to the inside face of the front wall's top plate, with the joist sitting in the hanger.
• At the back, the joist sits on or in the ledger. Use a joist hanger or skew-screw (4 × 100 mm bugles, 2 from each side) into the ledger.
• [ ] Step 5: Check each joist is level along its length and that all joists are at the same height. Adjust by shimming or re-cutting if any sit high.
• [ ] Verification: Walk under the joists. Ceiling height should be consistent at 2370 mm. Photo looking up.

Task 4.3: Add ceiling joist noggins and fan blocking

• [ ] Step 1: At mid-span (~1900 mm from each end), add a row of 190 × 45 noggins between every joist to stiffen and prevent rotation.
• [ ] Step 2: Mark and cut blocking for the ceiling fan: identify the centre of the room. The ceiling fan goes here. Add a 200 × 45 mm (or doubled 190 × 45) solid timber block between the two nearest ceiling joists at this point, screwed in tight. Mark this block with a marker pen so the sparky can find it later.
• [ ] Verification: Fan blocking is solid — push hard up against it; should feel rock solid.

Task 4.4: Confirm shed roof clearance and ceiling cavity ventilation

Summer heat: The air space between your new ceiling and the shed's metal roof will get extremely hot in summer. Without ventilation, this trapped air radiates heat down through the ceiling and degrades insulation performance.

• [ ] Step 1: Confirm there is adequate clearance between the top of the ceiling joists and the shed roof structure (minimum 100 mm, ideally 200+ mm). If the shed has ridge vents, wall vents, or gaps at the eaves, this space is already passively ventilated — note where.
• [ ] Step 2: If the shed roof space is sealed (no existing ventilation), consider adding whirlybird vents or passive vents to the shed itself. This is a separate decision — flag it now and revisit in Phase 15.
• [ ] Verification: Clearance measured. Existing ventilation paths identified or upgrade flagged for later.

Phase 4 verification: Back wall battened with ventilated cavity, ceiling joists installed at correct span and depth, fan blocking in place, roof space ventilation assessed. Photo of complete frame from inside the room.

Phase 5: Door & Window Opening Prep

Task 5.1: Confirm door opening

• [ ] Step 1: Measure the door rough opening: should be 870 wide × 2070 tall. Adjust if needed by repositioning the lintel or jack studs.
• [ ] Step 2: Check the rough opening is square (diagonals equal).

Task 5.2: Prepare window reveals

The existing shed windows need timber reveals (jamb extensions) to bring the window frame flush with the new interior wall surface (back wall battens + plasterboard total ~75 mm out from the shed wall).

• [ ] Step 1: For each window, measure window frame width and height.
• [ ] Step 2: Cut 90 × 19 mm pine to make a 4-sided reveal frame: top, bottom, left, right.
• [ ] Step 3: Don't fix the reveals yet — they go on after insulation but before plasterboard.

Phase 5 verification: Door opening square and dimensioned, reveal timber cut and ready.

Phase 6: Sparky Rough-In

Goal: Cable, back boxes, ceiling fittings, smoke alarm cable all in walls and ceiling, certified by sparky.

Task 6.1: Walk through with sparky

• [ ] Step 1: Schedule the sparky for a half-day visit. Walls and ceiling joists must be up; insulation and plasterboard must NOT be up yet.
• [ ] Step 2: Walk through the room with sparky and the spec Section 6 (electrical fittings table). Mark on the studs/joists with a marker pen where every fitting goes:
• GPOs (8 doubles)
• Light switches (3-gang at door)
• Ceiling downlights (4)
• Ceiling fan position (already blocked)
• Wall sconces (2 bedside)
• Smoke alarm
• Ethernet outlet
• [ ] Step 3: Sparky pulls cable from the existing shed sub-board (or the house, whichever is best), runs cable through the stud cavities, installs back boxes screwed to studs, ceiling-mount brackets for downlights, and the fan blocking confirmation.
• [ ] Step 4: Sparky leaves the cable tails out of each back box for fit-off later. Tape over the back box openings to prevent dust contamination during plasterboard work.

Task 6.2: Add additional blocking for fittings

• [ ] Step 1: While sparky is there, identify any wall items that need solid timber blocking behind the plasterboard:
• Curtain track / blind brackets above the windows → add 90 × 19 timber across the back of the wall at 2050 mm AFL above each window opening.
• Wall sconces → add 90 × 19 blocking horizontally between the studs at 1200 mm AFL, on each side of the bed.
• Wardrobe wall anchors (if you'll secure the wardrobe to the wall for tip safety) → add blocking at 1900 mm AFL where the wardrobe back will be.
• [ ] Step 2: Mark each blocking location with painters tape on the stud face so you can find it after plasterboard.

Phase 6 verification: Sparky has signed off rough-in inspection, cables tagged at sub-board, all boxes labelled. Owner has documented (photographed) every back box position and blocking position with a tape measure visible in the photo for future reference.

Phase 7: Insulation

Goal: All insulation in place with no gaps, ready for vapour layer.

Task 7.1: Side and front wall batts

• [ ] Step 1: Buy R2.5 polyester wall batts (430 × 1160, sized for 450 ctr studs). Quantity: ~50 m² of wall area / batt size = ~50 batts.
• [ ] Step 2: PPE: long sleeves, gloves, mask, glasses.
• [ ] Step 3: Friction-fit batts into every stud cavity in front, left, right walls. Cut around back boxes with a Stanley knife — fit batt behind the cable, not in front of it. The cable should be embedded in the batt, not crushed against it.
• [ ] Step 4: Double-check no cavity is left empty. Look from the side — every bay should be uniformly white/grey.

Task 7.2: Back wall batts

• [ ] Step 1: Buy R2.0 batts sized for the 50 mm batten cavity (typical: high-density 50 mm × 600 mm × 1200 mm).
• [ ] Step 2: Friction-fit between the back wall battens. Cut around windows neatly.
• [ ] Step 3: Around the windows, ensure the batts fully fill the gap between the shed wall and the new wall lining plane — no voids.

Task 7.3: Ceiling batts

• [ ] Step 1: Buy R4.0 ceiling batts (430 × 1160, suit 450 ctr joists). Quantity: 25 m² of ceiling / batt area = ~25 batts. Buy 30 to allow for full coverage including over the room perimeter. The 190 mm deep ceiling joists accommodate R4.0 batts (~200 mm thick) without compression.
• [ ] Step 2: Lay batts into the ceiling joist cavities from below (work from a step ladder with the joists exposed). Each batt should friction-fit snugly into the 190 mm deep cavity between joists.
• [ ] Step 3: Important: Don't compress batts. R-value depends on loft. Batts should sit flush with the joist undersides, not bulging below or recessed above. If they don't fit fluffy, you bought the wrong size — return and exchange.
• [ ] Step 4: Batts must cover the entire ceiling area including over the wall top plates at the perimeter — no thermal weak spots.

Phase 7 verification: Every wall and ceiling cavity insulated, no gaps, no compression, no batts crushed by cables. Photo of each wall and the ceiling.

Phase 8: Vapour Control Layer (Critical)

Goal: A continuous, taped, sealed plastic membrane on the warm-in-winter (interior) side of all walls and ceiling, preventing interior moisture from reaching the cold metal shed back wall and the cool insulation core.

This is the single most important quality detail in the build. Take your time.

Task 8.1: Materials

• [ ] Step 1: Buy:
• 200 µm builder's plastic, 4 m wide × 25 m roll (~$60). One roll covers the whole room.
• Vapour-tight sealing tape: Tescon Vana / Pro Clima or similar — wide red building tape (~$60 for a roll). Don't use cheap clear packing tape — it fails within months.
• Acoustic sealant: Tremco or similar gun-grade sealant (~$15 per tube, buy 2).

Task 8.2: Install vapour layer on walls

• [ ] Step 1: Starting from one corner, staple the plastic to the interior face of the wall studs across the entire wall surface. Run plastic continuously from floor to ceiling, taping seams every 200 mm.
• [ ] Step 2: Where two sheets of plastic meet, overlap by 200 mm, then run vapour-tight tape along the full overlap.
• [ ] Step 3: At every back box, cut a small X in the plastic, push the back box through, then tape the cut closed against the back box rim with vapour-tight tape.
• [ ] Step 4: At the floor, tuck the plastic down into the bottom plate / subfloor join, and run a bead of acoustic sealant between the plastic edge and the floor.
• [ ] Step 5: At the ceiling, leave 100 mm of plastic going up onto the ceiling joists for later overlap with ceiling vapour layer.

Task 8.3: Install vapour layer on the back wall (most important)

• [ ] Step 1: Same process. Plastic over the back wall battens, sealed continuously.
• [ ] Step 2: Around the window frames: the plastic must seal directly to the window frame to prevent any air leaks. Use vapour-tight tape stuck to the window frame on one edge and the plastic on the other.
• [ ] Step 3: At the corners where back wall meets side walls, overlap by 200 mm with the side wall vapour layer and tape.

Task 8.4: Install vapour layer on the ceiling

• [ ] Step 1: Plastic stapled to the underside of the ceiling joists.
• [ ] Step 2: Overlap and tape with the wall vapour layers at every wall-ceiling junction.
• [ ] Step 3: Cut and seal around any ceiling penetrations (downlight cables, fan cable, smoke alarm).

Task 8.5: Inspection

• [ ] Step 1: Walk the room slowly. Look at every junction, every penetration, every overlap. Any gap, any unsealed cut, any flapping edge — fix it.
• [ ] Step 2: Pay special attention to: corners (3 surfaces meet), back box penetrations, window perimeters, where plastic meets the floor.
• [ ] Verification: The room should be visually wrapped in a continuous plastic envelope. Photo of every wall and the ceiling. This is your most important documentation in case you ever have a moisture problem.

Phase 9: Plasterboard Hanging

Goal: Walls and ceiling clad in 10 mm plasterboard, ready for setting.

Task 9.1: Materials

• [ ] Step 1: Calculate plasterboard quantity:
• Walls: ~50 m² + back wall ~25 m² = 75 m²
• Ceiling: 25 m²
• Total: 100 m²
• Each sheet 2400 × 1200 = 2.88 m² → 35 sheets minimum, buy 38 for waste.
• [ ] Step 2: Buy:
• 10 mm plasterboard sheets × 38 (~$420)
• 30 mm plasterboard screws × 3 boxes (1000 screws total) (~$45)
• Bullnose external corner beads × 4 (for door return) (~$15)
• Square stop beads (for window edges) × 8 (~$30)
• Joint tape (paper) × 1 roll 75 m (~$10)
• [ ] Step 3: Arrange delivery — these sheets are heavy and awkward.

Task 9.2: Hang the ceiling first

Always do the ceiling first so wall sheets can support its edges.

• [ ] Step 1: Two people minimum for the ceiling. Or rent a ply lifter.
• [ ] Step 2: Lift the first sheet to the ceiling, position with the long edge perpendicular to the joists, butt against one wall.
• [ ] Step 3: Drive plasterboard screws into every joist along each edge and through the field of the sheet. Spacing: 200 mm at edges, 300 mm in the field. Screws should be driven slightly proud of the surface — stop just before the paper tears.
• [ ] Step 4: Continue with adjacent sheets, butting tight, staggering joints so end joints don't line up across rows.
• [ ] Step 5: Cut the last row to width with a Stanley knife (score the paper, snap, cut the back paper).

Task 9.3: Hang the walls

• [ ] Step 1: Start with full sheets at the corners. Run sheets vertically (long edge floor to ceiling) where wall height permits — easier joints. If the wall is taller than 2400 mm you'll have a horizontal joint mid-wall; place this at a consistent height across all walls.
• [ ] Step 2: Screw to every stud at 200 mm edges, 300 mm field.
• [ ] Step 3: At the door opening, cut sheets to fit around the door rough opening. Don't cover the opening.
• [ ] Step 4: At the windows, stop — install the window reveals first (Task 9.4 below) before plasterboarding around the windows. Then cut sheets to fit around the reveals.

Task 9.4: Install window reveals

• [ ] Step 1: Fit the cut 90 × 19 reveal pieces around each window so they extend from the window frame out to the new wall plane (flush with the back wall vapour layer).
• [ ] Step 2: Screw or nail into the window frame and the back wall battens.
• [ ] Step 3: Continue plasterboarding around the window, butting plasterboard tight to the reveal edge.

Task 9.5: Install corner beads

• [ ] Step 1: At every external corner (door return, window reveal external corners), nail or screw a bullnose corner bead. These give the corners a finished, durable edge.
• [ ] Step 2: At window plasterboard edges that abut the timber reveal, install square stop beads for a clean edge.

Phase 9 verification: All ceiling and wall surfaces clad. No exposed insulation. All corners beaded. Photo of each wall and the ceiling.

Phase 10: Plasterboard Set & Sand

Goal: Smooth, paint-ready walls and ceiling.

Task 10.1: Materials

• [ ] Step 1: Buy:
• Joint compound (pre-mixed, 20 kg bucket) × 2 (~$60)
• 100 mm jointing knife (~$15)
• 200 mm jointing knife / hawk (~$25)
• Sanding pole + 120 grit screens (~$30)

Task 10.2: First coat — tape and bed

• [ ] Step 1: Apply a thin layer of joint compound over each joint with the 100 mm knife.
• [ ] Step 2: Press paper joint tape into the wet compound, smooth flat with the knife.
• [ ] Step 3: Apply a thin cover coat over the tape.
• [ ] Step 4: Fill all screw heads with a swipe of compound.
• [ ] Step 5: Cover all corner beads with a 200 mm wide layer of compound, feathered to the wall.
• [ ] Step 6: Let dry 24 hours.

Task 10.3: Second coat

• [ ] Step 1: Light sanding of any high spots from coat 1.
• [ ] Step 2: Apply second coat with the 200 mm knife, wider than the first coat, feathered at edges.
• [ ] Step 3: Re-cover screw heads.
• [ ] Step 4: Dry 24 hours.

Task 10.4: Third coat

• [ ] Step 1: Sand again, lightly.
• [ ] Step 2: Final thin skim coat with the 200 mm knife. Spread very thin, feather very wide.
• [ ] Step 3: Dry 24 hours.

Task 10.5: Final sand

• [ ] Step 1: Use the pole sander with 120 grit.
• [ ] Step 2: Sand every joint and screw spot until smooth and feathered into the surrounding plasterboard.
• [ ] Step 3: Run your hand across joints — should feel imperceptible.
• [ ] Step 4: Vacuum all dust off walls, ceiling, and floor.
• [ ] Verification: Hold a worklight at a low angle to the wall — any bumps, ridges, or tape lines visible? Spot fix with another thin coat and re-sand.

Phase 10 verification: Walls and ceiling smooth, dust-free, ready for paint. Photo.

Phase 11: Sparky Fit-Off

Task 11.1: Sparky returns

• [ ] Step 1: Schedule sparky's fit-off visit. ~Half day.
• [ ] Step 2: Sparky cuts plasterboard at every back box, fits switches/GPOs, installs downlights, ceiling fan, sconces, smoke alarm.
• [ ] Step 3: Sparky tests every circuit and certifies the work.
• [ ] Step 4: Get a copy of the certificate of compliance. Keep this with house papers — it's the proof the work was done by a licensed sparky if anything ever happens.

Phase 11 verification: Every fitting installed and working, smoke alarm tested, certificate received.

Phase 12: Painting

Task 12.1: Materials

• [ ] Step 1: Buy:
• Dulux Wash & Wear in Natural White (or similar warm off-white), low-sheen finish for walls, 10 L (~$130)
• Dulux Ceiling White, flat finish, 10 L (~$80)
• Dulux 1-Step Acrylic Sealer Undercoat × 4 L (~$50)
• Roller frame, microfibre roller covers × 4
• Cutting-in brush 50 mm × 2
• Drop sheets, painters tape

Task 12.2: Prep

• [ ] Step 1: Mask edges of any fittings, GPOs, switches with painters tape.
• [ ] Step 2: Lay drop sheets over the protected ply floor.
• [ ] Step 3: Wipe down all surfaces with a slightly damp cloth to remove residual dust.

Task 12.3: Undercoat

• [ ] Step 1: Apply 1 coat of acrylic sealer undercoat to all walls and ceiling. Cut in edges first with brush, then roll the field.
• [ ] Step 2: Dry 4 hours.

Task 12.4: Ceiling, 2 coats

• [ ] Step 1: Cut in ceiling perimeter with brush.
• [ ] Step 2: Roll ceiling in long parallel passes, keeping a wet edge.
• [ ] Step 3: Dry 4 hours, second coat.

Task 12.5: Walls, 2 coats

• [ ] Step 1: Same process. Cut in then roll.
• [ ] Step 2: Two coats minimum.
• [ ] Verification: Walk the room with a worklight at a low angle. Any roller marks, brush strokes, missed spots → touch up.

Phase 12 verification: Painted, dry. Photo.

Phase 13: Vinyl Plank Flooring & Skirtings

Task 13.1: Materials

• [ ] Step 1: Buy:
• LVP planks in light oak finish, total 28 m² (10% waste over 25.3 m²) — ~$1100
• 2 mm vinyl underlay if click-lock (skip if glue-down)
• Vinyl plank adhesive if glue-down (~$80)
• 90 × 12 mm pine skirting × 22 m total perimeter (~$80)
• Pine quad or scotia × 22 m if needed for subfloor expansion gap (~$30)
• Skirting nails or paintable adhesive

Task 13.2: Install vinyl plank

• [ ] Step 1: Remove the cardboard floor protection. Sweep and vacuum the ply subfloor thoroughly.
• [ ] Step 2: Acclimatise the LVP in the room for 48 hours before laying (boxes laid flat, opened).
• [ ] Step 3: Decide direction: planks running parallel to the long axis (6700 mm direction) makes the room feel longer.
• [ ] Step 4: Start at one wall. Leave a 5 mm expansion gap at the wall edge (use spacer blocks).
• [ ] Step 5: Lay planks row by row, click-locking edges (or trowelling adhesive and pressing planks for glue-down).
• [ ] Step 6: Cut end planks to fit using a sharp Stanley knife and a straightedge (score and snap).
• [ ] Step 7: Cut around door opening with care.
• [ ] Verification: Floor is flat, tight, no gaps between planks, expansion gap consistent at all walls.

Task 13.3: Install skirtings

• [ ] Step 1: Cut 90 × 12 pine skirting to length for each wall, mitring or coping internal corners.
• [ ] Step 2: Pre-paint the skirting before installing (same wall paint colour).
• [ ] Step 3: Fix to the wall with a bead of paintable construction adhesive on the back and 2 nails per length into the bottom plate.
• [ ] Step 4: Fill nail holes, touch up paint.
• [ ] Verification: Skirting tight to floor and wall, mitres clean, paint touched up.

Phase 13 verification: Flooring and skirting complete. Photo.

Phase 14: Door Hanging & Trim

Task 14.1: Hang the door

• [ ] Step 1: Buy a pre-hung internal door, 820 × 2040, hinged right. ~$280.
• [ ] Step 2: Test fit in the rough opening.
• [ ] Step 3: Shim the jamb with timber wedges so the jamb is plumb both ways and the gap around the door is consistent (3 mm typical).
• [ ] Step 4: Screw the jamb to the king studs through the shim points with 75 mm bugles.
• [ ] Step 5: Test the door swing: opens freely, latches properly, doesn't bind.

Task 14.2: Install door handle

• [ ] Step 1: Buy a matte black or matte brass internal door handle/latch set (~$40).
• [ ] Step 2: Drill the handle and latch holes per the handle template.
• [ ] Step 3: Install handle, latch, strike plate.

Task 14.3: Architrave

• [ ] Step 1: Buy 70 × 12 pine architrave, ~7 m for both sides of the door.
• [ ] Step 2: Mitre cut at top corners.
• [ ] Step 3: Pre-paint, then nail to the door jamb / wall edge.

Phase 14 verification: Door installed, swings cleanly, latches, looks finished.

Phase 15: Window Blinds, Vent, Air Sealing

Task 15.1: Roller blinds

• [ ] Step 1: Measure the existing window openings (now with reveals installed).
• [ ] Step 2: Order or buy blockout roller blinds × 2, light cream or natural linen-look. ~$200 total.
• [ ] Step 3: Mount per blind instructions (usually 4 screws into the curtain track blocking installed in Phase 6).

Task 15.2: Ventilation (critical for a bedroom)

A sealed, insulated room used for sleeping needs adequate fresh air supply. A single 100 mm passive vent to the shed interior is not sufficient on its own — it provides no fresh air when the shed is closed up.

• [ ] Step 1: Confirm the back-wall windows open to the exterior (outside the shed, not just into the shed). If yes, these are your primary fresh air source — cross-ventilation when both are open. If the windows open only into the shed interior, you need a mechanical solution (Step 4 below).
• [ ] Step 2: Cut a circular hole in the front wall plasterboard at high level (~2200 mm AFL), 150 mm diameter (upgrade from 100 mm for better airflow).
• [ ] Step 3: Install a closeable wall vent (Bunnings, ~$30). Vent goes through to the rest of the shed. This provides cross-ventilation on summer nights when the shed is open, and air circulation for the room at other times.
• [ ] Step 4: If the back-wall windows do NOT open to outside, or if you want ventilation when windows are closed (winter, rain): install a 150 mm inline extract fan (~$120) ducted from the room through the front wall into the shed, with a timer or humidity switch. This gives mechanical ventilation for sleeping. Alternatively, duct through the shed wall to outside if access is practical.
• [ ] Step 5: Test ventilation: close the door, open one window and the wall vent. You should feel air moving through the room. If no perceptible airflow, the passive setup isn't working — go to the mechanical option in Step 4.

Task 15.3: Air sealing kit

• [ ] Step 1: Door bottom: stick-on brush seal across the bottom of the door interior face (~$15).
• [ ] Step 2: Door perimeter: foam tape around the door jamb where it meets the door (~$10).
• [ ] Step 3: Window frames: re-caulk any gaps around the window frame to wall reveal junction with paintable acrylic (~$15).
• [ ] Verification: Stand in the room, close the door, look for daylight around the door perimeter. None should be visible.

Phase 15 verification: Window treatments installed, ventilation tested (cross-ventilation confirmed or mechanical extract fan installed), air sealing complete.

Phase 16: Furnishing & Final Touches

Task 16.1: Move furniture in

• [ ] Step 1: Take delivery of furniture (purchased separately per Section 7 of spec):
• Queen bed frame + mattress + base
• Bedside tables × 2
• Wardrobe (IKEA PAX 150 or similar) — assemble on site
• Desk + office chair
• Reading armchair + side table
• Floor rug
• Bedding, throws, cushions, art, plants
• [ ] Step 2: Position per Layout A (spec Section 7):
• Queen bed centered on back wall
• Nightstands either side under windows
• Wardrobe on left wall against back corner
• Desk on right wall against back corner, chair facing wall
• Armchair front-left corner with side table
• Rug centered, in front of bed
• [ ] Step 3: Anchor the wardrobe to the wall (use the blocking installed in Phase 6).

Task 16.2: Plug in heating and lighting

• [ ] Step 1: Plug in the 2000 W oil column heater on the dedicated GPO.
• [ ] Step 2: Test all light fittings, fan, outlets one final time.
• [ ] Step 3: Test the smoke alarm.

Task 16.3: Final cleanup

• [ ] Step 1: Vacuum, dust, wipe down surfaces.
• [ ] Step 2: Make the bed.
• [ ] Step 3: Hang the art, position the plants.

Task 16.4: Take "after" photos

• [ ] Step 1: Photo from each corner.
• [ ] Step 2: Photo from the doorway looking in.
• [ ] Step 3: Photo of the desk setup, the bed setup, the lounge corner.
• [ ] Step 4: Save in the project folder alongside the "before" photos. You'll want them later.

Final Verification

• [ ] Everything in spec Section 7 (furniture) is in place
• [ ] Every electrical fitting in spec Section 6 is installed and working
• [ ] Door swings cleanly, latches, locks
• [ ] Both windows open, close, and lock
• [ ] Wall vent opens and closes
• [ ] Smoke alarm tested
• [ ] No visible gaps in finish work
• [ ] No daylight visible around door
• [ ] Heater works
• [ ] Ceiling fan works on all speeds
• [ ] Ventilation confirmed: cross-ventilation works with windows + vent, or mechanical extract fan installed
• [ ] Both windows confirmed as viable emergency egress (clear opening ≥ 850 × 600 mm, sill ≤ 1500 mm AFL)
• [ ] Sparky's certificate of compliance is filed with house documents

Project complete. Move in. Sleep. Work. Hang out. Send photos.

Notes for the Builder

On pace: Don't try to rush this. The framing phase (3) can be done in a long weekend. Insulation + vapour layer (7-8) is a long weekend. Plasterboard (9-10) is the bottleneck — the setting compound needs 24 hours between coats, so it spans a week minimum. Plan accordingly.

On asking for help: Plasterboard hanging is much easier with two people. Ceiling sheets are basically impossible solo. Recruit a friend or hire a labourer for a day for the hanging phase only.

On variance from plan: If reality differs from spec — measurements wrong, materials unavailable, door doesn't fit — stop, photograph, and ask before improvising. Improvising in framing is fine; improvising in vapour control is dangerous.

On the "off the books" choice: Two things you must do regardless of compliance status: (1) licensed sparky for all wiring (legal requirement, insurance protection), (2) functioning smoke alarm. Everything else is your call.