Job takeoff
Garden room or backyard office takeoff
Build a detached, insulated timber-framed garden room (a backyard office or studio): the base on ground screws, concrete piers or a slab, a framed and sheathed shell under a flat EPDM roof, clad walls, the door and windows, a lined and decorated room and the power supply from the house, with the base and the frame listed and never sized.
A takeoff is the trade word for the shopping list a job produces — every material, and how much of each, worked out by its own cited calculator.
- 15Measurements in
- 3130Trades out
Choose the build-up
Each layer changes the materials below; the dimensions stay the same.
Calculators behind the other choices:
Calculators behind the other choices:
Compare one layer at these dimensions, with the rest of the build-up held as you have it:
Give the job once
Every figure on the right follows these, in the units you choose.
Been given a quote for this job?
Paste it into the garden room quote check: each line is read against these same calculators — what it leaves out, what it adds, and what to ask.
Check the quoteEvery trade, from those dimensions
then change a dimension, and each line shows what moved.
| Trade | Quantity | |
|---|---|---|
Turf, topsoil and ground dug out over the footprintTrench Excavation & Backfill Volume CalculatorTurf and topsoil lifted over the whole footprint to the depth you gave, or the ground taken down to formation where a slab goes in. The working's excavation line is the ground as it lies; the headline adds a quarter for the way dug soil bulks up once loose, the same figure the spoil skip below is sized on.
Why this quantity?
Resting on
The loose-volume allowance: set by the Garden room or backyard office takeoff. Change any other figure on the Trench Excavation & Backfill Volume Calculator | 2.01 yd³ | |
Concrete for the piersCircular Pier / Cylinder Concrete CalculatorPiers under the floor's bearers no more than 1.8 m (about 6 ft) apart each way, with one at each end of every row, each poured in a 12 in (305 mm) round form 36 in (914 mm) deep, with the calculator's waste allowance. The layout, the diameter and the depth are the page's own figures, standing in for the designer's: the depth follows the ground and, where the ground freezes, the frost depth the local code sets. Each pier's hole is dug by hand or with an auger, and its spoil is about the concrete's volume.
Why this quantity?
Resting on
The waste factor: the calculator's working figure, a trade convention. Change any other figure on the Circular Pier / Cylinder Concrete Calculator | 1.1 yd³ | |
Weed membrane and stone laid in the dig (gravel or hardcore)Gravel Base Layer Tonnage CalculatorStone to the depth of the dig over the footprint, by weight at the calculator's opening density: compacted hardcore under a slab, or gravel over a weed membrane under a raised base, laid round the screws or piers so it sheds water and keeps weeds from growing up into the void. The membrane is listed as work.
Why this quantity?
Resting on
Change any other figure on the Gravel Base Layer Tonnage Calculator | 2.98 tons | |
Floor insulation boards, cut between the joistsFoam Board Insulation CalculatorRigid boards cut between the floor joists over the whole floor frame, held up on battens or clips, at the calculator's opening sheet and cutting allowance. How thick they are is set by the energy rules the room falls under, or by the owner where none apply; the page leaves that choice open.
Why this quantity?
Resting on
The cutting waste: the calculator's working figure, a trade convention. Change any other figure on the Foam Board Insulation Calculator | 5 sheets (4x8 ft) | |
Wall studs, the walls' frame (studwork)Framing Stud CalculatorStuds at the calculator's opening centres along the four walls taken as one run, with the page's four extra studs at the door set and at each window. The corner posts, two or three studs at each of the four corners, the head and sole plates and the lintels (headers) over the openings are not in the count, and no member is sized.
Why this quantity?
Resting on
| 48 studs | |
Sheathing on the walls, OSB or plywoodPlywood and OSB Sheet Calculator (Subfloor, Wall and Roof)Sheets over the outside of the frame, round all four walls to the height clad, with the calculator's cutting allowance; the door and windows are cut out of whole sheets and not taken off.
Why this quantity?
Resting on
The waste factor: the calculator's working figure, a trade convention. Change any other figure on the Plywood and OSB Sheet Calculator (Subfloor, Wall and Roof) | 13 sheets (4x8 ft) | |
Roof deck, OSB or plywoodPlywood and OSB Sheet Calculator (Subfloor, Wall and Roof)Sheets over the roof joists to the overhang on every side, measured on plan: a fall of a few degrees adds nothing a sheet count shows. The firring pieces that set the fall, where the joists are not already sloped, are listed as work.
Why this quantity?
Resting on
The waste factor: the calculator's working figure, a trade convention. Change any other figure on the Plywood and OSB Sheet Calculator (Subfloor, Wall and Roof) | 6 sheets (4x8 ft) | |
Rigid insulation boards, warm roofFoam Board Insulation CalculatorRigid boards over the whole deck, on the vapour control layer (listed as work), at the calculator's opening sheet and cutting allowance, fixed through to the deck as the membrane's maker details. Where the maker asks for a second deck over the boards, it is the roof deck row again.
Why this quantity?
Resting on
The cutting waste: the calculator's working figure, a trade convention. Change any other figure on the Foam Board Insulation Calculator | 6 sheets (4x8 ft) | |
EPDM membrane over the roofEPDM Single-Ply Roofing Roll CalculatorThe roof on plan with its overhangs, plus the strip turned down over the edge trims all round, at the calculator's opening roll of 46.5 m² (500 sq ft). A roof this size is covered from one sheet cut to size, so read the count as the area check and order the sheet by the roof's length and depth plus the turn-downs. The edge trims, the adhesive and the primer are listed as work.
Why this quantity?
Resting on
Change any other figure on the EPDM Single-Ply Roofing Roll Calculator | 1 roll | |
Gutter and downpipe (downspout) along the eavesGutter CalculatorOne run of gutter along the low edge of the roof, in the calculator's stock sections. The same working counts one downpipe (downspout) off it; where that pipe discharges, into a water butt, a drain or a soakaway (a dry well), is the owner's choice, and a drain or soakaway is listed as work.
Why this quantity?
Resting on
| 2 x 10 ft sections | |
Breather membrane (house wrap) on the wallsHouse Wrap CalculatorThe breather membrane wraps the sheathed frame on all four sides up to the top of the cladding, with the calculator's lap allowance. At the door set and at each window it is slit and folded back into the opening, so no opening comes off the area.
Why this quantity?
Resting on
The lap allowance: the calculator's working figure, a trade convention. | 1 roll | |
Flashing tape round the door set's openingWindow Opening Flashing Membrane CalculatorSelf-adhered tape sealing the door set's framed opening to the breather membrane: across the sill, up both sides and over the head, each piece carried beyond the corners by the calculator's own run-past, with its allowances.
Why this quantity?
Resting on
The waste allowance: the calculator's working figure, a trade convention. Change any other figure on the Window Opening Flashing Membrane Calculator | 31.9 ft | |
Flashing tape round each window openingWindow Opening Flashing Membrane CalculatorTape for the windows, sized from each one's framed opening: the sill piece first, then the sides and the head lapped over it, with the calculator's allowances.
Why this quantity?
Resting on
The waste allowance: the calculator's working figure, a trade convention. Change any other figure on the Window Opening Flashing Membrane Calculator | 41.8 ft | |
Furring (battens) fixed upright on the wallsRain-Screen Cladding Furring Strip CalculatorFurring strips run up the wall over the house wrap at the calculator's opening centres, over the studs, round all four walls, each the height clad, leaving a drained gap behind the siding.
Why this quantity?
Resting on
Change any other figure on the Rain-Screen Cladding Furring Strip Calculator | 288 ft | |
Siding (cladding): lap or plank, vinyl, wood or fibre cementSiding CalculatorHorizontal siding over the furring on all four walls up to the height clad, with the calculator's waste allowance: counted in squares of 100 sq ft (9.29 m²) with imperial showing, and in square metres with metric. It deducts its own standard sizes, 15 sq ft (1.4 m²) for each window and 21 sq ft (1.95 m²) for the one door, so a door set wider than a single door leaves a little extra.
Why this quantity?
Resting on
The waste factor: the calculator's working figure, a trade convention. | 3.49 squares | |
Trims outside: corners, heads and revealsExterior Flashing Layout Trim Sheet CalculatorTrims up the four corners to the height clad, over the head and down both jambs of the door set, and round all four sides of every window, counted in stock pieces: 3 m (9 ft 10 in) lengths with the upright boards, the page's 10 ft (3.05 m) pieces with siding. The insect mesh closers at the foot and head of the cavity are listed as work.
Why this quantity?
Resting on
Change any other figure on the Exterior Flashing Layout Trim Sheet Calculator | 8 sheets | |
Mastic (caulk) round the openingsFiber-Cement Siding Caulk Joint Volume CalculatorExterior mastic (caulk in North America) run as one bead where each frame meets the cladding, all four sides of the door set and of each window, worked as a volume from the calculator's opening joint, 6 mm (1/4 in) square. To turn it into cartridges, divide by what one holds, 310 ml (10.5 US fl oz) for a British cartridge or 10.1 US fl oz (299 ml) for an American tube, with a little over for what stays in the nozzle.
Why this quantity?
Resting on
Change any other figure on the Fiber-Cement Siding Caulk Joint Volume Calculator | 0.1591 gal | |
Exterior stain or paint on the clad wallsExterior Paint CalculatorTwo coats on the outside walls, with the door set and the windows left out. The page spreads each US gallon (3.79 L) over 300 sq ft (28 m²) a coat, a rate it fixes, and rounds up to the next half gallon; rough-sawn timber and end grain soak up more, and a stain's tin may promise less cover.
Why this quantity?
Resting on
| 2.5 gallons | |
Trench for the supply cable, dug and backfilledTrench Excavation & Backfill Volume CalculatorA trench along the cable's route from the house, a spade's width and as deep as the electrician sets. The dug volume is the working's excavation line, and that soil goes back over the cable with warning tape laid in it, so none of it is in the skips. The headline is the calculator's loose backfill with its opening allowance of 15% for compacting it: a check that the soil dug out will fill the trench again, not a quantity to buy. The cable is the electrician's and listed as work.
Why this quantity?
Resting on
The loose-volume allowance: the calculator's working figure, a trade convention. Change any other figure on the Trench Excavation & Backfill Volume Calculator | 4.11 yd³ | |
Insulation batts, wallsMineral Wool Insulation Batt CalculatorBatts filling the stud bays round the four walls inside, to the room's height less the door and windows, at the calculator's opening pack and allowance.
Why this quantity?
Resting on
The waste allowance: the calculator's working figure, a trade convention. Change any other figure on the Mineral Wool Insulation Batt Calculator | 6 packages | |
Vapour control layer on the wallsVapor Barrier CalculatorA polythene or foil-faced vapour control layer (vapor retarder) on the warm side of the wall batts, less the door and windows, lapped at the calculator's allowance and taped at every joint and round every box.
Why this quantity?
Resting on
The seam overlap allowance: the calculator's working figure, a trade convention. | 1 roll | |
Ceiling board (plasterboard or drywall)Ceiling Plasterboard (Gypsum Board) Sheet CalculatorBoard for the ceiling inside the walls, fixed to the underside of the roof joists, at the calculator's opening sheet and cutting allowance.
Why this quantity?
Resting on
The waste allowance: the calculator's working figure, a trade convention. Change any other figure on the Ceiling Plasterboard (Gypsum Board) Sheet Calculator | 4 sheets | |
Board on the walls inside (plasterboard or drywall)Ceiling Plasterboard (Gypsum Board) Sheet CalculatorBoard for the four walls inside, the room's height all round less the door set and the windows at their own sizes, at the calculator's opening sheet and cutting allowance; the row runs on the ceiling-sheet page because that page counts any area.
Why this quantity?
Resting on
The waste allowance: the calculator's working figure, a trade convention. Change any other figure on the Ceiling Plasterboard (Gypsum Board) Sheet Calculator | 9 sheets | |
Joint compound (mud), walls and ceilingDrywall Joint Compound CalculatorJoint compound (mud) to bed the tape and to fill and finish over every board in the room, walls and ceiling as one area, at the calculator's coverage for three coats plus what is lost in the pan and to sanding: counted in whole boxes when imperial is showing, and as a weight of ready-mixed compound when metric is.
Why this quantity?
Resting on
The pan and sanding loss: the calculator's working figure, a trade convention. Change any other figure on the Drywall Joint Compound Calculator | 1 x 4.5 gal box | |
Joint tape, walls and ceilingDrywall Joint Tape CalculatorPaper tape for every joint between boards, at the rate the calculator works for its opening 8 ft (2.4 m) sheets, plus the internal angles: where the ceiling meets the walls all the way round, and the room's four corners from floor to ceiling. The outside corners at the door set and the windows' returns are finished with corner bead, which this row leaves out.
Why this quantity?
Resting on
The waste allowance: the calculator's working figure, a trade convention. Change any other figure on the Drywall Joint Tape Calculator | 228.27 ft | |
Paint on the walls insidePaint CalculatorPaint for the walls inside, two coats, with the door set and each window left out at their own sizes, at the calculator's opening spread rate. A thinned mist coat on fresh skim, or a primer on taped board, comes first and is listed as preparation.
Why this quantity?
Resting on
| 1.23 gal | |
Paint on the ceilingCeiling Paint CalculatorTwo coats over the ceiling at the calculator's opening spread rate.
Why this quantity?
Resting on
| 0.5621 gal | |
Laminate or vinyl plank floorLVP, Laminate & Engineered Floor CalculatorPacks for the floor inside the walls at the calculator's opening pack coverage and a simple lay, over the deck and any underlay the plank's maker asks for.
Why this quantity?
Resting on
The layout waste: the calculator's working figure, a trade convention. Change any other figure on the LVP, Laminate & Engineered Floor Calculator | 6 packs | |
Skirting (baseboard) round the room; architraves (casings) not countedBaseboard & Trim CalculatorSkirting round the room less the door set, in stock lengths with the calculator's cutting allowance. The page takes a single door's width off, so a wide door set leaves the row a little over. The architraves (casings) round the door set and the windows, and any window boards (stools), are fixed with it and are not counted.
Why this quantity?
Resting on
The cutting waste: the calculator's working figure, a trade convention. | 43.87 linear ft | |
Skip (dumpster) or muck away for the spoilSkip & Dumpster Size CalculatorThe turf and topsoil lifted from under the room, a quarter bigger once dug, sized as soil. Soil uses up a skip's weight allowance before its volume, so the loads to book are the working's count by weight. Where the base stands on piers, the soil from each hole, about as much as the concrete poured into it, adds to this unless it is spread on the beds.
Why this quantity?
Resting on
Change any other figure on the Skip & Dumpster Size Calculator | 2.01 yd³ | |
Skip or bags for the offcuts and packagingSkip & Dumpster Size CalculatorAn allowance rather than anything measured: as if a layer 125 mm (5 in) deep covered the footprint, to hold the offcuts of cladding and board, the pallets and the wrapping. It is light waste, kept out of the soil skip so each load goes to the right place.
Why this quantity?
Resting on
Change any other figure on the Skip & Dumpster Size Calculator | 1.97 yd³ | |
Turf, topsoil and ground dug out over the footprintTrench Excavation & Backfill Volume CalculatorTurf and topsoil lifted over the whole footprint to the depth you gave, or the ground taken down to formation where a slab goes in. The working's excavation line is the ground as it lies; the headline adds a quarter for the way dug soil bulks up once loose, the same figure the spoil skip below is sized on.
Why this quantity? | 1.5 m³ (loose) | |
Weed membrane and stone laid in the dig (gravel or hardcore)Gravel Base Layer Tonnage CalculatorStone to the depth of the dig over the footprint, by weight at the calculator's opening density: compacted hardcore under a slab, or gravel over a weed membrane under a raised base, laid round the screws or piers so it sheds water and keeps weeds from growing up into the void. The membrane is listed as work.
Why this quantity? | 2.64 metric tons | |
Floor insulation boards, cut between the joistsFoam Board Insulation CalculatorRigid boards cut between the floor joists over the whole floor frame, held up on battens or clips, at the calculator's opening sheet and cutting allowance. How thick they are is set by the energy rules the room falls under, or by the owner where none apply; the page leaves that choice open.
Why this quantity? | 5 sheets (2400x1200 mm) | |
Wall studs, the walls' frame (studwork)Framing Stud CalculatorStuds at the calculator's opening centres along the four walls taken as one run, with the page's four extra studs at the door set and at each window. The corner posts, two or three studs at each of the four corners, the head and sole plates and the lintels (headers) over the openings are not in the count, and no member is sized.
Why this quantity? | 48 studs | |
Sheathing on the walls, OSB or plywoodPlywood and OSB Sheet Calculator (Subfloor, Wall and Roof)Sheets over the outside of the frame, round all four walls to the height clad, with the calculator's cutting allowance; the door and windows are cut out of whole sheets and not taken off.
Why this quantity? | 13 sheets (2440x1220 mm) | |
Roof deck, OSB or plywoodPlywood and OSB Sheet Calculator (Subfloor, Wall and Roof)Sheets over the roof joists to the overhang on every side, measured on plan: a fall of a few degrees adds nothing a sheet count shows. The firring pieces that set the fall, where the joists are not already sloped, are listed as work.
Why this quantity? | 6 sheets (2440x1220 mm) | |
Rigid insulation boards, warm roofFoam Board Insulation CalculatorRigid boards over the whole deck, on the vapour control layer (listed as work), at the calculator's opening sheet and cutting allowance, fixed through to the deck as the membrane's maker details. Where the maker asks for a second deck over the boards, it is the roof deck row again.
Why this quantity? | 6 sheets (2400x1200 mm) | |
EPDM membrane over the roofEPDM Single-Ply Roofing Roll CalculatorThe roof on plan with its overhangs, plus the strip turned down over the edge trims all round, at the calculator's opening roll of 46.5 m² (500 sq ft). A roof this size is covered from one sheet cut to size, so read the count as the area check and order the sheet by the roof's length and depth plus the turn-downs. The edge trims, the adhesive and the primer are listed as work.
Why this quantity? | 1 roll | |
Gutter and downpipe (downspout) along the eavesGutter CalculatorOne run of gutter along the low edge of the roof, in the calculator's stock sections. The same working counts one downpipe (downspout) off it; where that pipe discharges, into a water butt, a drain or a soakaway (a dry well), is the owner's choice, and a drain or soakaway is listed as work.
Why this quantity? | 2 x 4 m sections | |
Breather membrane (house wrap) on the wallsHouse Wrap CalculatorThe breather membrane wraps the sheathed frame on all four sides up to the top of the cladding, with the calculator's lap allowance. At the door set and at each window it is slit and folded back into the opening, so no opening comes off the area.
Why this quantity? | 1 roll | |
Flashing tape round the door set's openingWindow Opening Flashing Membrane CalculatorSelf-adhered tape sealing the door set's framed opening to the breather membrane: across the sill, up both sides and over the head, each piece carried beyond the corners by the calculator's own run-past, with its allowances.
Why this quantity? | 9.68 m | |
Flashing tape round each window openingWindow Opening Flashing Membrane CalculatorTape for the windows, sized from each one's framed opening: the sill piece first, then the sides and the head lapped over it, with the calculator's allowances.
Why this quantity? | 12.32 m | |
Counter-battens, uprightRain-Screen Cladding Furring Strip CalculatorThe first layer: treated counter-battens fixed upright over the breather membrane at the calculator's opening centres, round all four walls and as long as the height clad, so water that gets behind the boards runs down and out at the foot.
Why this quantity? | 86.4 m | |
Battens across the wall, for the upright boardsRain-Screen Cladding Furring Strip CalculatorThe second layer: battens run level across the counter-battens, a row at every step of the calculator's opening spacing from the foot of the cladding to its top, each row going right round the room. The page counts them turned on its side, taking the height clad as its width and the room's perimeter as the run of every strip, so the strips it counts are the rows.
Why this quantity? | 98 m | |
Cladding boards and cover battens (board-and-batten siding)Board and Batten Siding CalculatorUpright boards round the whole room on a 175 mm (7 in) module, a 150 mm (6 in) board and then a 25 mm (1 in) gap, with a cover batten closing each gap and one at each end of the run, all cut to the height clad. The short boards above and below the openings are cut from the same run, so the door set and the windows are not deducted.
Why this quantity? | 80 boards | |
Trims outside: corners, heads and revealsExterior Flashing Layout Trim Sheet CalculatorTrims up the four corners to the height clad, over the head and down both jambs of the door set, and round all four sides of every window, counted in stock pieces: 3 m (9 ft 10 in) lengths with the upright boards, the page's 10 ft (3.05 m) pieces with siding. The insect mesh closers at the foot and head of the cavity are listed as work.
Why this quantity? | 8 sheets | |
Mastic (caulk) round the openingsFiber-Cement Siding Caulk Joint Volume CalculatorExterior mastic (caulk in North America) run as one bead where each frame meets the cladding, all four sides of the door set and of each window, worked as a volume from the calculator's opening joint, 6 mm (1/4 in) square. To turn it into cartridges, divide by what one holds, 310 ml (10.5 US fl oz) for a British cartridge or 10.1 US fl oz (299 ml) for an American tube, with a little over for what stays in the nozzle.
Why this quantity? | 0.5256 L | |
Exterior stain or paint on the clad wallsExterior Paint CalculatorTwo coats on the outside walls, with the door set and the windows left out. The page spreads each US gallon (3.79 L) over 300 sq ft (28 m²) a coat, a rate it fixes, and rounds up to the next half gallon; rough-sawn timber and end grain soak up more, and a stain's tin may promise less cover.
Why this quantity? | 9.46 L | |
Trench for the supply cable, dug and backfilledTrench Excavation & Backfill Volume CalculatorA trench along the cable's route from the house, a spade's width and as deep as the electrician sets. The dug volume is the working's excavation line, and that soil goes back over the cable with warning tape laid in it, so none of it is in the skips. The headline is the calculator's loose backfill with its opening allowance of 15% for compacting it: a check that the soil dug out will fill the trench again, not a quantity to buy. The cable is the electrician's and listed as work.
Why this quantity? | 3.1 m³ (loose) | |
Insulation batts, wallsMineral Wool Insulation Batt CalculatorBatts filling the stud bays round the four walls inside, to the room's height less the door and windows, at the calculator's opening pack and allowance.
Why this quantity? | 6 packages | |
Vapour control layer on the wallsVapor Barrier CalculatorA polythene or foil-faced vapour control layer (vapor retarder) on the warm side of the wall batts, less the door and windows, lapped at the calculator's allowance and taped at every joint and round every box.
Why this quantity? | 1 roll | |
Ceiling board (plasterboard or drywall)Ceiling Plasterboard (Gypsum Board) Sheet CalculatorBoard for the ceiling inside the walls, fixed to the underside of the roof joists, at the calculator's opening sheet and cutting allowance.
Why this quantity? | 4 sheets | |
Board on the walls inside (plasterboard or drywall)Ceiling Plasterboard (Gypsum Board) Sheet CalculatorBoard for the four walls inside, the room's height all round less the door set and the windows at their own sizes, at the calculator's opening sheet and cutting allowance; the row runs on the ceiling-sheet page because that page counts any area.
Why this quantity? | 10 sheets | |
Skim coat over the boards, walls and ceilingSkim Coat Plaster CalculatorA skim of finish plaster over every board in the room, walls and ceiling, with the door set and the windows left out, at the calculator's opening thickness and allowance, over scrim tape bedded on each joint. The drying time before the first coat of paint is listed as work.
Why this quantity? | 98.51 kg | |
Paint on the walls insidePaint CalculatorPaint for the walls inside, two coats, with the door set and each window left out at their own sizes, at the calculator's opening spread rate. A thinned mist coat on fresh skim, or a primer on taped board, comes first and is listed as preparation.
Why this quantity? | 4.78 L | |
Paint on the ceilingCeiling Paint CalculatorTwo coats over the ceiling at the calculator's opening spread rate.
Why this quantity? | 2.08 L | |
Laminate or vinyl plank floorLVP, Laminate & Engineered Floor CalculatorPacks for the floor inside the walls at the calculator's opening pack coverage and a simple lay, over the deck and any underlay the plank's maker asks for.
Why this quantity? | 6 packs | |
Skirting (baseboard) round the room; architraves (casings) not countedBaseboard & Trim CalculatorSkirting round the room less the door set, in stock lengths with the calculator's cutting allowance. The page takes a single door's width off, so a wide door set leaves the row a little over. The architraves (casings) round the door set and the windows, and any window boards (stools), are fixed with it and are not counted.
Why this quantity? | 13.35 m | |
Skip (dumpster) or muck away for the spoilSkip & Dumpster Size CalculatorThe turf and topsoil lifted from under the room, a quarter bigger once dug, sized as soil. Soil uses up a skip's weight allowance before its volume, so the loads to book are the working's count by weight. Where the base stands on piers, the soil from each hole, about as much as the concrete poured into it, adds to this unless it is spread on the beds.
Why this quantity? | 1.5 m³ | |
Skip or bags for the offcuts and packagingSkip & Dumpster Size CalculatorAn allowance rather than anything measured: as if a layer 125 mm (5 in) deep covered the footprint, to hold the offcuts of cladding and board, the pallets and the wrapping. It is light waste, kept out of the soil skip so each load goes to the right place.
Why this quantity? | 1.5 m³ |
Estimates, not a quote. Each row gives its base, the allowance on top, the adjusted figure and what to order; change an allowance on the row, or open its reasoning to see every figure it rests on. A trade's own page carries what it does not cover — open the one you are about to order against.
Labour and programme
Person-hours for the rows going in, from trade rules of thumb: a range for each piece of work, never a price.
- Turf, topsoil and ground dug out over the footprint5.5 h (3.1–12)
- Concrete for the piers2.0 h (1.0–4.2)
- Weed membrane and stone laid in the dig (gravel or hardcore)1.2 h (0.5–3.7)
- Floor insulation boards, cut between the joists2.2 h (1.2–6.0)
- Wall studs, the walls' frame (studwork)7.7 h (4.2–15)
- Sheathing on the walls, OSB or plywood4.5 h (2.6–9.1)
- Roof deck, OSB or plywood2.1 h (1.2–4.2)
- Rigid insulation boards, warm roof2.6 h (1.4–7.2)
- EPDM membrane over the roof3.2 h (1.6–6.3)
- Gutter and downpipe (downspout) along the eaves1.7 h (0.9–3.4)
- Breather membrane (house wrap) on the walls1.4 h (0.7–2.7)
- Flashing tape round the door set's opening4.0 h (1.0–8.0)
- Flashing tape round each window opening8.0 h (2.0–16)
- Furring (battens) fixed upright on the walls6.1 h (3.5–12)
- Siding (cladding): lap or plank, vinyl, wood or fibre cement18 h (9.7–36)
- Trims outside: corners, heads and reveals8.1 h (4.6–16)
- Mastic (caulk) round the openings1.8 h (0.9–3.7)
- Exterior stain or paint on the clad walls5.3 h (2.9–12)
- Trench for the supply cable, dug and backfilled12 h (6.8–27)
- Insulation batts, walls2.3 h (1.1–5.0)
- Vapour control layer on the walls1.4 h (0.7–2.7)
- Ceiling board (plasterboard or drywall)1.3 h (0.7–2.4)
- Board on the walls inside (plasterboard or drywall)2.9 h (1.6–5.4)
- Joint compound (mud), walls and ceiling5.3 h (3.0–11)
- Paint on the walls inside4.1 h (2.3–9.2)
- Paint on the ceiling1.9 h (1.0–4.2)
- Laminate or vinyl plank floor2.9 h (1.6–5.7)
- Skirting (baseboard) round the room; architraves (casings) not counted2.4 h (1.3–5.3)
- Skip or bags for the offcuts and packaging1.5 h (0.8–4.5)
About 124 person-hours in all, between 64 and 261.
Trade by trade
- Labourer1 labourer4 days
- Carpenter2 carpenters3 days
- Roofer2 roofershalf a day
- Glazier2 glaziers1 day
- Painter1 painter1½ days
- Drywaller1 drywaller + 1 labourerhalf a day
- Taper1 taper + 1 labourerhalf a day
- Floor layer1 floor layerhalf a day
About 10½ days, one trade after another at eight hours a day. Left out: drying and curing, deliveries, inspections, trades overlapping.
2 rows carry no hours of their own
- Joint tape, walls and ceiling: counted with Joint compound (mud), walls and ceiling
- Skip (dumpster) or muck away for the spoil: counted with Turf, topsoil and ground dug out over the footprint and Trench for the supply cable, dug and backfilled
Labour and programme
Person-hours for the rows going in, from trade rules of thumb: a range for each piece of work, never a price.
- Turf, topsoil and ground dug out over the footprint5.4 h (3.0–12)
- Weed membrane and stone laid in the dig (gravel or hardcore)1.2 h (0.5–3.6)
- Floor insulation boards, cut between the joists2.2 h (1.2–6.0)
- Wall studs, the walls' frame (studwork)7.7 h (4.2–15)
- Sheathing on the walls, OSB or plywood4.5 h (2.6–9.1)
- Roof deck, OSB or plywood2.1 h (1.2–4.2)
- Rigid insulation boards, warm roof2.6 h (1.4–7.1)
- EPDM membrane over the roof3.1 h (1.6–6.3)
- Gutter and downpipe (downspout) along the eaves1.7 h (0.9–3.4)
- Breather membrane (house wrap) on the walls1.3 h (0.7–2.7)
- Flashing tape round the door set's opening4.0 h (1.0–8.0)
- Flashing tape round each window opening8.0 h (2.0–16)
- Counter-battens, upright6.0 h (3.5–12)
- Battens across the wall, for the upright boards6.9 h (3.9–14)
- Trims outside: corners, heads and reveals7.9 h (4.5–16)
- Mastic (caulk) round the openings1.8 h (0.9–3.6)
- Exterior stain or paint on the clad walls5.2 h (2.9–12)
- Trench for the supply cable, dug and backfilled12 h (6.7–27)
- Insulation batts, walls2.4 h (1.2–5.3)
- Vapour control layer on the walls1.4 h (0.7–2.9)
- Ceiling board (plasterboard or drywall)1.3 h (0.7–2.4)
- Board on the walls inside (plasterboard or drywall)3.2 h (1.8–6.0)
- Skim coat over the boards, walls and ceiling5.8 h (3.4–12)
- Paint on the walls inside4.3 h (2.4–9.6)
- Paint on the ceiling1.9 h (1.0–4.2)
- Laminate or vinyl plank floor2.9 h (1.6–5.7)
- Skirting (baseboard) round the room; architraves (casings) not counted2.4 h (1.3–5.3)
- Skip or bags for the offcuts and packaging1.5 h (0.8–4.5)
About 111 person-hours in the rows that carry them, between 58 and 235.
Trade by trade
- Labourer1 labourer3½ days
- Carpenter2 carpenters2½ days
- Roofer2 roofershalf a day
- Glazier2 glaziers1 day
- Painter1 painter1½ days
- Drywaller1 drywaller + 1 labourerhalf a day
- Plasterer1 plastererhalf a day
- Floor layer1 floor layerhalf a day
About 10 days, one trade after another at eight hours a day. Left out: drying and curing, deliveries, inspections, trades overlapping.
2 rows carry no hours of their own
- Cladding boards and cover battens (board-and-batten siding): its rate is per m²; this row gives boards
- Skip (dumpster) or muck away for the spoil: counted with Turf, topsoil and ground dug out over the footprint and Trench for the supply cable, dug and backfilled
Setups you have saved
The build-up, the dimensions and any allowance you changed — kept on this device, and reusable on any job. Your prices are not copied in: they stay in your price book, so a setup never holds a stale one.
How far does a budget go?
At your own prices, with this build-up unchanged.
About this job
A garden room is a small building standing on its own at the end of a garden, and it has to do everything a house wall does with no house to lean on: shed rain driven at all four sides, stay warm enough to work in through a winter, and bring power a long way from the house. Nothing is shared with the house, so every layer from the ground to the roof membrane is part of the job, and the base is decided before anything else is ordered.
The base follows the units shown. With metric showing it opens on ground screws (screw piles, or helical piles in North America): steel screws the supplier designs, drives to a depth and a torque and levels to take the frame, so this page lists them and measures nothing of them. With imperial showing it opens on concrete piers poured in round cardboard forms (tubes), no more than 1.8 m (about 6 ft) apart each way with one at each end of every row. A slab on a stone bed is the third choice in either. Under each, the turf and topsoil come off the footprint and stone goes back into the dig, over a weed membrane under a raised base so that nothing grows beneath the floor and the air gap under it stays open to the outside.
The walls are timber studs sheathed in OSB or plywood and wrapped in a breather membrane (house wrap), then battened out (furred out) so the cladding has a drained, ventilated gap behind it. The units pick the cladding as well: upright boards with cover battens, on battens across the wall and upright counter-battens, in metric, and horizontal siding on upright furring strips in imperial. The roof is flat or falls gently to its back edge, decked and covered in one sheet of EPDM, as a warm roof with rigid boards over the deck or a cold roof with batts between the joists and air moving over them.
Inside, the floor is insulated between its joists and the walls between their studs, with a vapour control layer on the warm side before the board goes up. The finish follows the units: board skimmed in plaster in metric, taped and finished drywall in imperial. Power comes from the house through a buried cable (steel-wire armoured in the UK, direct-burial cable or wire in conduit in North America) in a trench this page measures; the cable, its protection at each end and its earthing are the electrician's work, listed here and signed off by nobody on this site.
How each line reads
- Base
- What the calculator gives for these dimensions, before anything is added.
- Allowance
- Cutting waste, a lap or spare stock — named, with where it comes from, and changeable on the row.
- Adjusted
- The base with its allowance on top.
- Order
- What to buy: the adjusted figure in whole boards, bags, rolls or lengths.
The order this happens in
Quantities do not tell you the sequence, and on this job the sequence is where the money goes wrong.
- Settle the room's size and where it stands against permitted development or a planning application, and building control or a permit; have the screws, piers or slab chosen by their supplier or the designer; and trace any drain, pipe or cable under the footprint and along the cable's route to the house.
- Peg the footprint out square by its diagonals, strip the turf and topsoil, and set the base: the screws driven and levelled, the piers dug and poured in their tubes, or the slab's stone bed compacted, its membrane laid and the concrete cast in its formwork.
- Lay the weed membrane and the stone under a raised base, then build the floor frame on a strip of damp-proof course over each bearing, insulate between the joists and deck it.
- Frame and sheathe the walls, lift the roof joists on and set the fall, deck the roof and, for a warm roof, lay the vapour control layer and the boards; fix the edge trims, bond the EPDM and dress it down over them, then put the gutter up along the low edge and take its downpipe to a water butt, a drain or a soakaway.
- Wrap the walls, fit and tape the door and windows, batten out, hang the cladding with its trims and the insect mesh closers at its foot and head, seal round every frame, and stain or paint the boards unless they are left to weather.
- Dig the cable trench from the house, lay the cable or its duct with warning tape over it and backfill, and run the first-fix cables inside the room.
- Insulate between the studs and, on a cold roof, between the joists with the eaves vents clear; fix the vapour control layer, board the ceiling and the walls, and skim or tape them, letting a skim dry before any paint.
- Paint the walls and ceiling, lay the floor, fix the skirting and the architraves, connect the lights and sockets, have the circuits tested, and take away the spoil and the offcuts.
What this takeoff does not cover
- What the base and the frame must be to carry the room: the ground screws' number, length and rating, the piers' size, depth and spacing, the slab's thickness, and the size of the bearers, floor joists, studs and roof joists. Each appears as work, or as a count at the page's spacing, never with a size; the ground screws are their supplier's design.
- Planning: whether a room this tall, this near a boundary and covering this much of the plot stays within England's permitted development or needs an application, and whether the building regulations' exemption for a small detached outbuilding applies, which the local authority answers. In the US and Canada, the setback, height and lot-coverage rules for an accessory structure, and whether it needs a permit, are the local zoning and building department's.
- Whether the house's main board (service panel) has the capacity for the room's circuit, the cable's size and protection, and the earthing arrangement at the room: the electrician's decisions. The supply is listed as work and only its trench is measured.
- A water supply, a toilet, a sink or a shower in the room, and any foul drainage from it.
- Whether a soakaway (a dry well) will drain in the ground and how big it must be, where the downpipe runs to one; the drain run to it is listed as work, not measured.
- Decking, a veranda, steps up to the door, and a path from the house.
- Choosing the door set and the windows: a French, bifold or sliding door set, timber, uPVC (vinyl) or aluminium frames, their glazing and their locks. The page takes their openings as entered and counts the tape, the mastic and the trims that fit them.
- Heating, cooling or mechanical ventilation for the room.
- Architraves (casings) round the door set and the windows, and any window boards (stools): fixed with the skirting as its work, and not counted.
- The roof's fall: firring pieces (tapered strips) on the joists, or joists set to a slope, are listed as work, and the roof rows are measured on plan.
- A roof covered in anything but a single EPDM sheet: torch-on felt, GRP, or a pitched roof in tiles or shingles has rows of its own on the flat roof replacement and pitched roof pages.
Quote check
Been given a quote for this job?
Paste it into the garden room quote check. Every line of it is read against these same calculators and your measurements. Quantities only, never prices.
What it leaves out
Every line this takeoff has that nothing on the quote reads as.
What it adds
Labour, removal, hire, fees — each named for what it is.
What to ask
One list of questions, ready to copy. Never a verdict.
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Frequently asked questions
- What does the garden room takeoff give for a typical job?
- Opened at Length, along the front 4 m · Depth, front to back 3 m · Height clad outside 2.4 m · Room height, floor to ceiling 2.2 m · Wall thickness, sheathing to lining 0.12 m · Roof overhang, each edge 0.15 m · Door opening width 1.5 m · Door opening height 2 m · Windows 2 · Window opening width, each 0.9 m · Window opening height, each 1 m · Supply cable route, house to room 15 m · Cable trench depth 0.6 m · Dig over the footprint 0.1 m · Membrane turned over each roof edge 0.1 m, it orders: Turf, topsoil and ground dug out over the footprint, 1.5 m³ (loose); Weed membrane and stone laid in the dig (gravel or hardcore), 2.64 metric tons; Floor insulation boards, cut between the joists, 5 sheets (2400x1200 mm); Wall studs, the walls' frame (studwork), 48 studs; Sheathing on the walls, OSB or plywood, 13 sheets (2440x1220 mm); Roof deck, OSB or plywood, 6 sheets (2440x1220 mm); Rigid insulation boards, warm roof, 6 sheets (2400x1200 mm); EPDM membrane over the roof, 1 roll; Gutter and downpipe (downspout) along the eaves, 2 x 4 m sections; Breather membrane (house wrap) on the walls, 1 roll; Flashing tape round the door set's opening, 9.68 m; Flashing tape round each window opening, 12.3 m; Counter-battens, upright, 86.4 m; Battens across the wall, for the upright boards, 98 m; Cladding boards and cover battens (board-and-batten siding), 80 boards; Trims outside: corners, heads and reveals, 8 sheets; Mastic (caulk) round the openings, 0.53 L; Exterior stain or paint on the clad walls, 9.46 L; Trench for the supply cable, dug and backfilled, 3.1 m³ (loose); Insulation batts, walls, 6 packages; Vapour control layer on the walls, 1 roll; Ceiling board (plasterboard or drywall), 4 sheets; Board on the walls inside (plasterboard or drywall), 10 sheets; Skim coat over the boards, walls and ceiling, 98.5 kg; Paint on the walls inside, 4.78 L; Paint on the ceiling, 2.08 L; Laminate or vinyl plank floor, 6 packs; Skirting (baseboard) round the room; architraves (casings) not counted, 13.4 m; Skip (dumpster) or muck away for the spoil, 1.5 m³; Skip or bags for the offcuts and packaging, 1.5 m³. Opened at Length, along the front 13 ft · Depth, front to back 10 ft · Height clad outside 8 ft · Room height, floor to ceiling 7 ft · Wall thickness, sheathing to lining 4.75 in · Roof overhang, each edge 6 in · Door opening width 5 ft · Door opening height 6.5 ft · Windows 2 · Window opening width, each 3 ft · Window opening height, each 3.5 ft · Supply cable route, house to room 49 ft · Cable trench depth 2 ft · Dig over the footprint 4 in · Membrane turned over each roof edge 4 in: Turf, topsoil and ground dug out over the footprint, 2.01 yd³; Concrete for the piers, 1.1 yd³; Weed membrane and stone laid in the dig (gravel or hardcore), 2.98 tons; Floor insulation boards, cut between the joists, 5 sheets (4x8 ft); Wall studs, the walls' frame (studwork), 48 studs; Sheathing on the walls, OSB or plywood, 13 sheets (4x8 ft); Roof deck, OSB or plywood, 6 sheets (4x8 ft); Rigid insulation boards, warm roof, 6 sheets (4x8 ft); EPDM membrane over the roof, 1 roll; Gutter and downpipe (downspout) along the eaves, 2 x 10 ft sections; Breather membrane (house wrap) on the walls, 1 roll; Flashing tape round the door set's opening, 31.9 ft; Flashing tape round each window opening, 41.8 ft; Furring (battens) fixed upright on the walls, 288 ft; Siding (cladding): lap or plank, vinyl, wood or fibre cement, 3.49 squares; Trims outside: corners, heads and reveals, 8 sheets; Mastic (caulk) round the openings, 0.16 gal; Exterior stain or paint on the clad walls, 2.5 gallons; Trench for the supply cable, dug and backfilled, 4.11 yd³; Insulation batts, walls, 6 packages; Vapour control layer on the walls, 1 roll; Ceiling board (plasterboard or drywall), 4 sheets; Board on the walls inside (plasterboard or drywall), 9 sheets; Joint compound (mud), walls and ceiling, 1 x 4.5 gal box; Joint tape, walls and ceiling, 228 ft; Paint on the walls inside, 1.23 gal; Paint on the ceiling, 0.56 gal; Laminate or vinyl plank floor, 6 packs; Skirting (baseboard) round the room; architraves (casings) not counted, 43.9 linear ft; Skip (dumpster) or muck away for the spoil, 2.01 yd³; Skip or bags for the offcuts and packaging, 1.97 yd³. Every figure follows the dimensions you give it.
- Which calculators does the garden room takeoff run?
- 25 calculators, for 31 lines: Trench Excavation & Backfill Volume Calculator, Circular Pier / Cylinder Concrete Calculator, Gravel Base Layer Tonnage Calculator, Foam Board Insulation Calculator, Framing Stud Calculator, Plywood and OSB Sheet Calculator (Subfloor, Wall and Roof), EPDM Single-Ply Roofing Roll Calculator, Gutter Calculator, House Wrap Calculator, Window Opening Flashing Membrane Calculator, Rain-Screen Cladding Furring Strip Calculator, Siding Calculator, Exterior Flashing Layout Trim Sheet Calculator, Fiber-Cement Siding Caulk Joint Volume Calculator, Exterior Paint Calculator, Mineral Wool Insulation Batt Calculator, Vapor Barrier Calculator, Ceiling Plasterboard (Gypsum Board) Sheet Calculator, Drywall Joint Compound Calculator, Drywall Joint Tape Calculator, Paint Calculator, Ceiling Paint Calculator, LVP, Laminate & Engineered Floor Calculator, Baseboard & Trim Calculator, Skip & Dumpster Size Calculator. Each has a page of its own with its formula and its sources; the takeoff runs them all on one set of dimensions.23 calculators, for 30 lines: Trench Excavation & Backfill Volume Calculator, Gravel Base Layer Tonnage Calculator, Foam Board Insulation Calculator, Framing Stud Calculator, Plywood and OSB Sheet Calculator (Subfloor, Wall and Roof), EPDM Single-Ply Roofing Roll Calculator, Gutter Calculator, House Wrap Calculator, Window Opening Flashing Membrane Calculator, Rain-Screen Cladding Furring Strip Calculator, Board and Batten Siding Calculator, Exterior Flashing Layout Trim Sheet Calculator, Fiber-Cement Siding Caulk Joint Volume Calculator, Exterior Paint Calculator, Mineral Wool Insulation Batt Calculator, Vapor Barrier Calculator, Ceiling Plasterboard (Gypsum Board) Sheet Calculator, Skim Coat Plaster Calculator, Paint Calculator, Ceiling Paint Calculator, LVP, Laminate & Engineered Floor Calculator, Baseboard & Trim Calculator, Skip & Dumpster Size Calculator. Each has a page of its own with its formula and its sources; the takeoff runs them all on one set of dimensions.
- What does the garden room takeoff leave out?
- 11 things, each named on this page: What the base and the frame must be to carry the room; Planning; Whether the house's main board (service panel) has the capacity for the room's circuit, the cable's size and protection, and the earthing arrangement at the room; A water supply, a toilet, a sink or a shower in the room, and any foul drainage from it; Whether a soakaway (a dry well) will drain in the ground and how big it must be, where the downpipe runs to one; the drain run to it is listed as work, not measured; Decking, a veranda, steps up to the door, and a path from the house; Choosing the door set and the windows; Heating, cooling or mechanical ventilation for the room; Architraves (casings) round the door set and the windows, and any window boards (stools): fixed with the skirting as its work, and not counted; The roof's fall; A roof covered in anything but a single EPDM sheet.
- Can I check a quote for this job against the takeoff?
- Yes. The garden room quote check reads a quote's lines against these same calculators and your measurements, and reports what it leaves out, what it adds and what to ask. It reads quantities, never prices.