Fictional demo. Computed live by the estimating engine from a template's default answers, default labour rates and dated catalogue allowances. It is not a real business, customer or supplier price.
Live demo
Garden room / home office
8.2 m² internal · £45,964.80 inc. VAT
£45,964.80
Selling price inc. VAT
£38,304.00
Before VAT
8.2 m²
Internal floor area · £4,694/m²
4 wks
401 person-hours of labour
Cost to selling price
Materials£14,757.95Labour (at cost)£12,025.20Provisional allowances£1,800.00Plant hire£380.00Direct cost£28,963.15Overheads — 10% of direct cost£2,896.32Contingency — 5% of direct cost£1,448.16Profit — 15% markup on cost£4,996.14Rounding to nearest £1.00£0.23Net selling price£38,304.00VAT at 20%£7,660.80Total£45,964.80
Pricing coverage
Cost backed by a price100%— of which verified (your prices)0%— of which catalogue allowances (dated 2026-09-24)52.3%— of which provisional allowances6.2%Lines missing a price0Stale prices0Assumptions that could move the price2
Selling price before VAT divided by internal floor area. A reasonableness check only — it does not replace the line-by-line estimate. Template status: provisional
By work package (at cost)
| Package | Materials | Labour | Allowances | Total |
|---|---|---|---|---|
| Preliminaries & site setup | £90.00 | £480.00 | £0.00 | £570.00 |
| Excavation & foundations | £357.50 | £1,356.90 | £0.00 | £1,714.40 |
| Floors | £791.00 | £827.40 | £0.00 | £1,618.40 |
| External walls | £6,117.35 | £3,408.30 | £0.00 | £9,525.65 |
| Roof | £1,825.10 | £2,058.00 | £0.00 | £3,883.10 |
| Windows & external doors | £2,810.00 | £510.00 | £0.00 | £3,320.00 |
| Drainage | £410.00 | £720.00 | £0.00 | £1,130.00 |
| Plumbing & heating | £95.00 | £30.00 | £0.00 | £125.00 |
| Electrical | £200.00 | £510.00 | £650.00 | £1,360.00 |
| Insulation & internal linings | £211.00 | £831.45 | £0.00 | £1,042.45 |
| Internal finishes | £321.00 | £1,203.15 | £0.00 | £1,524.15 |
| Scaffold & access | £450.00 | £0.00 | £0.00 | £450.00 |
| Plant hire | £380.00 | £0.00 | £0.00 | £380.00 |
| Waste removal | £1,080.00 | £0.00 | £0.00 | £1,080.00 |
| Deliveries | £0.00 | £0.00 | £250.00 | £250.00 |
| Testing & certification | £0.00 | £90.00 | £0.00 | £90.00 |
| Fees & approvals | £0.00 | £0.00 | £900.00 | £900.00 |
Provisional allowances (3)
Items that need a design, a supplier quotation or your confirmation. Edit the figure, or confirm it, on the review page. Material allowances appear on the customer's quote as provisional sums.
- Power supply from the house builder to confirm£650.00Armoured cable in a trench from the house consumer unit, with its own RCD. Distance not measured.
- Material deliveries builder to confirm£250.00Delivery charges depend on the supplier and order size. Confirmed against supplier baskets when prices are verified.
- Building control fees regulatory£900.00Plan check and inspection fees vary by council and project value. Allowance only; confirm with your local authority or approved inspector.
Assumptions (9)
- Under 2.5m high at the eaves and within permitted development limits; building regulations apply if over 30 m² or with sleeping accommodation.
- Foundations: trench fill 600mm wide × 0.6m deep in GEN1 concrete under all new external walls.
- Ground floor: 100mm concrete slab on 150mm compacted hardcore with 100mm PIR insulation.
- could move the price External walls: manufacturer-designed timber frame with insulated studs, breather membrane and a masonry or clad outer skin. The frame price is an allowance until the manufacturer quotes.
- Flat roof: warm-deck construction with 120mm PIR, 47×195 C24 joists at 400 centres with firrings to fall, epdm rubber roof membrane with adhesives & trims.
- could move the price Rainwater to a new soakaway at least 5m from the building; a percolation test may be required by building control.
- The existing consumer unit has spare capacity for the new circuits; if not, a new unit is extra.
- No planning application fee, party wall surveyor or planning drawings are included. Permitted development or existing consent is assumed.
- Work to comply with the building regulations applying in England; design by others where a design is required.
Materials — 63 lines (measured → with waste → purchased)
| Item | Measured | + waste | Buy | Unit price | Cost | Price status |
|---|---|---|---|---|---|---|
| Alloy tower scaffold hire per week access equipment · from access | 3 wk | 3 | 3 × week | £150.00 | £450.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Underground drainage pipe 110mm × 3m drainage · from drainage | 6 m | 6.60 | 3 × length | £14.00 | £42.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Bottle gully 110mm drainage · from drainage | 1 nr | 1 | 1 × each | £22.00 | £22.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Pea gravel 10mm drainage · from drainage | 1 m3 | 1.10 | 3 × bulk bag | £52.00 | £156.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Soakaway crate 1 m³ with membrane drainage · from drainage | 2 nr | 2 | 2 × each | £95.00 | £190.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| LED downlight (fire-rated, dimmable) electrical · from electrics | 4 nr | 4 | 4 × each | £9.00 | £36.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Socket/switch point: faceplate, back box, cable share electrical · from electrics | 6 nr | 6 | 6 × each | £22.00 | £132.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Mains smoke/heat alarm interlinked electrical · from electrics | 1 nr | 1 | 1 × each | £32.00 | £32.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Ready-mix concrete GEN1 (foundations) excavation foundations · from foundations | 2.52 m3 | 2.65 | 11 × m³ (0.25 m³ steps) | £32.50 | £357.50 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Aluminium bi-fold doors 2.4m wide ×1 external openings · from doors | 2.40 m | 2.40 | 3 × m | £820.00 | £2,460.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| uPVC double-glazed window (A-rated) per m² — 0.9×0.9m ×1 external openings · from windows | 0.81 m2 | 0.81 | 1 × m² | £350.00 | £350.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Concrete block 100mm 7.3N external walls · from below-dpc, timber-frame | 403.5 nr | 423.7 | 6 × pack of 72 | £130.00 | £780.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Breathable roofing membrane 50m² external walls · from timber-frame | 55.5 m2 | 63.8 | 2 × roll | £55.00 | £110.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Building sand external walls · from below-dpc, timber-frame | 0.53 m3 | 0.58 | 2 × bulk bag | £52.00 | £104.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Cavity/stud insulation 100mm external walls · from timber-frame | 27.8 m2 | 29.8 | 7 × pack | £30.00 | £210.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Insulated cavity closer 2.4m external walls · from timber-frame | 9.30 m | 9.30 | 4 × length | £6.00 | £24.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Cladding battens 25×50 treated external walls · from timber-frame | 69.4 m | 76.3 | 77 × m | £0.75 | £57.75 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Composite cladding board external walls · from timber-frame | 27.8 m2 | 30.5 | 31 × m² | £62.00 | £1,922.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| DPC 100mm × 30m external walls · from timber-frame | 28 m | 32.2 | 2 × roll | £9.00 | £18.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Steel cavity lintel 1200mm over window external walls · from timber-frame | 1 nr | 1 | 1 × each | £45.00 | £45.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Steel cavity lintel 3000mm over bifold external walls · from timber-frame | 1 nr | 1 | 1 × each | £150.00 | £150.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Timber frame wall panel kit (designed, supplied) external walls · from timber-frame | 27.8 m2 | 27.8 | 28 × m² | £95.00 | £2,660.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Stainless wall ties 225mm external walls · from timber-frame | 111 nr | 111 | 1 × box of 250 | £35.00 | £35.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Weep vent external walls · from timber-frame | 4 nr | 4 | 4 × each | £0.40 | £1.60 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Cement 25kg floors · from below-dpc, screed, timber-frame | 9.09 bag | 9.78 | 10 × bag | £6.50 | £65.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Damp-proof membrane 1200 gauge 4m × 25m floors · from slab | 8.16 m2 | 9.38 | 1 × roll | £45.00 | £45.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| MOT Type 1 sub-base 150mm compacted floors · from slab | 1.59 m3 | 1.75 | 4 × bulk bag | £48.00 | £192.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Reinforcement mesh A142 4.8m × 2.4m floors · from slab | 8.16 m2 | 9.38 | 1 × sheet | £32.00 | £32.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| PIR floor insulation 100mm floors · from slab | 8.16 m2 | 8.77 | 4 × sheet | £38.00 | £152.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Ready-mix concrete GEN3 100mm slab floors · from slab | 0.82 m3 | 0.86 | 4 × m³ (0.25 m³ steps) | £35.00 | £140.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Sharp sand floors · from slab, screed | 0.99 m3 | 1.06 | 3 × bulk bag | £55.00 | £165.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Drywall adhesive 25kg (dot and dab) insulation linings · from linings | 27.8 m2 | 29.1 | 10 × bag | £8.00 | £80.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Drywall screws 38mm box of 1000 insulation linings · from ceiling | 244.8 nr | 244.8 | 1 × box | £12.00 | £12.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Plasterboard 12.5mm 2400×1200 insulation linings · from linings, ceiling | 35.9 m2 | 39.5 | 14 × sheet | £8.50 | £119.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Angle beads to reveals internal finishes · from skim | 9.30 m | 9.30 | 4 × length | £2.00 | £8.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Emulsion paint 10L (mist + two coats ≈ 60 m²) internal finishes · from decorating | 35.9 m2 | 35.9 | 1 × tub | £32.00 | £32.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Laminate flooring 8mm (pack 2.2 m²) internal finishes · from flooring | 8.16 m2 | 8.81 | 5 × pack | £30.00 | £150.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Multi-finish plaster 25kg internal finishes · from skim | 35.9 m2 | 37.7 | 4 × bag | £9.50 | £38.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Satinwood 2.5L (≈ 20 m of skirting/architrave) internal finishes · from decorating | 9.20 m | 9.20 | 1 × tin | £28.00 | £28.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Scrim tape 90m internal finishes · from skim | 43.1 m | 43.1 | 1 × roll | £5.00 | £5.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| MDF skirting 145mm × 4.4m internal finishes · from skirting | 9.20 m | 10.1 | 3 × length | £12.00 | £36.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Laminate underlay 3mm (roll 15 m²) internal finishes · from flooring | 8.16 m2 | 8.81 | 1 × roll | £24.00 | £24.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| 1t dumper hire per day plant · from foundations | 1 day | 1 | 1 × day | £70.00 | £70.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| 1.5t mini digger hire per day plant · from foundations | 1 day | 1 | 1 × day | £95.00 | £95.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Cement mixer hire per week plant · from prelims | 3 wk | 3 | 3 × week | £45.00 | £135.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Plant delivery/collection plant · from foundations | 1 nr | 1 | 1 × each | £80.00 | £80.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Electric panel heater 1.5kW plumbing heating · from panel-heaters | 1 nr | 1 | 1 × each | £95.00 | £95.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Site toilet hire per week preliminaries · from prelims | 3 wk | 3 | 3 × week | £30.00 | £90.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Flat roof joists C24 47×195 @ 400 centres roof · from flat-roof | 41.4 m | 45.5 | 46 × m | £4.60 | £211.60 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| uPVC downpipe 68mm × 2.5m with clips & shoe roof · from flat-roof | 2 nr | 2 | 2 × each | £18.00 | £36.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| EPDM rubber roof membrane with adhesives & trims roof · from flat-roof | 18.2 m2 | 20.9 | 21 × m² | £16.00 | £336.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| uPVC fascia board 175mm × 5m roof · from flat-roof | 16.4 m | 18.0 | 4 × length | £32.00 | £128.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Firring strips (tapered) per m roof · from flat-roof | 41.4 m | 45.5 | 46 × m | £2.00 | £92.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| uPVC half-round gutter 112mm × 4m roof · from flat-roof | 16.4 m | 18.0 | 5 × length | £14.00 | £70.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Gutter bracket roof · from flat-roof | 16.4 nr | 16.4 | 17 × each | £1.30 | £22.10 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Gutter fittings (outlet, stop ends, unions) per run roof · from flat-roof | 2 nr | 2 | 2 × set | £25.00 | £50.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| OSB3 18mm 2440×1220 roof · from flat-roof | 33.1 m2 | 36.4 | 13 × sheet | £28.00 | £364.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Warm roof PIR insulation 120mm roof · from flat-roof | 16.6 m2 | 17.8 | 7 × sheet | £45.00 | £315.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| uPVC soffit board 300mm × 5m roof · from flat-roof | 16.4 m | 18.0 | 4 × length | £30.00 | £120.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Vapour control layer 50m² roof · from flat-roof | 16.6 m2 | 19.0 | 1 × roll | £42.00 | £42.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Wall plate 100×50 treated roof · from flat-roof | 14 m | 15.4 | 16 × m | £2.40 | £38.40 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Muck-away of excavated spoil (grab lorry) waste · from foundations | 2 nr | 2 | 2 × load | £380.00 | £760.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Skips for construction waste waste · from waste | 1 nr | 1 | 1 × each | £320.00 | £320.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
Labour — 29 activities
| Activity | Qty | Crew hrs | Person hrs | Rate basis | Cost |
|---|---|---|---|---|---|
| Excavate trenches and reduced level (machine) Groundworker · 0.60 h/m3 · min 8h · +4h setup | 8.04 m3 | 12 | 24 | 1× groundworker @ £30.00/hr + 1× labourer @ £30.00/hr blended | £720.00 |
| Place and level foundation concrete Groundworker · 0.80 h/m3 · min 4h | 2.52 m3 | 4 | 8 | 2× groundworker @ £30.00/hr blended | £240.00 |
| Blockwork below DPC Bricklayer · 0.70 h/m2 | 12.6 m2 | 8.82 | 13.23 | 1× bricklayer @ £30.00/hr + 0.5× labourer @ £30.00/hr blended | £396.90 |
| Hardcore, blind, DPM, insulation, mesh and pour slab Groundworker · 1.20 h/m2 · min 8h | 8.16 m2 | 9.79 | 19.58 | 2× groundworker @ £30.00/hr blended | £587.40 |
| Lay 65mm sand/cement screed Plasterer · 0.40 h/m2 · min 4h | 8.16 m2 | 4 | 8 | 1× plasterer @ £30.00/hr + 1× labourer @ £30.00/hr blended | £240.00 |
| Erect timber frame panels Carpenter / joiner · 0.60 h/m2 · min 8h | 27.8 m2 | 16.65 | 33.3 | 2× carpenter / joiner @ £30.00/hr blended | £999.00 |
| Blockwork outer skin Bricklayer · 0.70 h/m2 · min 8h | 27.8 m2 | 19.42 | 29.13 | 1× bricklayer @ £30.00/hr + 0.5× labourer @ £30.00/hr blended | £873.90 |
| Battens, membrane and cladding Carpenter / joiner · 0.80 h/m2 · min 8h | 27.8 m2 | 22.2 | 44.4 | 2× carpenter / joiner @ £30.00/hr blended | £1,332.00 |
| Wall ties, cavity insulation and closers Bricklayer · 0.10 h/m2 | 27.8 m2 | 2.78 | 2.78 | 1× bricklayer @ £30.00/hr blended | £83.40 |
| Bed lintels Bricklayer · 1.00 h/nr | 2 nr | 2 | 4 | 1× bricklayer @ £30.00/hr + 1× labourer @ £30.00/hr blended | £120.00 |
| Flat roof joists, firrings and deck Carpenter / joiner · 0.90 h/m2 · min 8h | 16.6 m2 | 14.9 | 29.8 | 2× carpenter / joiner @ £30.00/hr blended | £894.00 |
| Vapour control layer, insulation and upper deck Carpenter / joiner · 0.30 h/m2 | 16.6 m2 | 4.97 | 9.94 | 2× carpenter / joiner @ £30.00/hr blended | £298.20 |
| Lay epdm rubber roof membrane with adhesives & trims Roofer · 0.50 h/m2 · min 6h | 16.6 m2 | 8.28 | 16.56 | 2× roofer @ £30.00/hr blended | £496.80 |
| Fascia, soffit, guttering and downpipes Carpenter / joiner · 0.50 h/m · min 4h | 16.4 m | 8.2 | 12.3 | 1× carpenter / joiner @ £30.00/hr + 0.5× labourer @ £30.00/hr blended | £369.00 |
| Fit bi-fold doors and threshold Carpenter / joiner · 6.00 h/nr | 1 nr | 6 | 12 | 2× carpenter / joiner @ £30.00/hr blended | £360.00 |
| Fit windows, seal and make good Carpenter / joiner · 2.50 h/nr | 1 nr | 2.5 | 5 | 2× carpenter / joiner @ £30.00/hr blended | £150.00 |
| Excavate and install soakaway with rainwater run Groundworker · 12.00 h/nr | 1 nr | 12 | 24 | 2× groundworker @ £30.00/hr blended | £720.00 |
| Electrical first fix: cables, back boxes, circuits Electrician · 1.10 h/nr · min 4h | 10 nr | 11 | 11 | 1× electrician @ £30.00/hr blended | £330.00 |
| Electrical second fix: faceplates, fittings, connection Electrician · 0.60 h/nr · min 3h | 10 nr | 6 | 6 | 1× electrician @ £30.00/hr blended | £180.00 |
| Test, certify and notify (Part P / equivalent) Electrician · 3.00 h/nr | 1 nr | 3 | 3 | 1× electrician @ £30.00/hr blended | £90.00 |
| Fix and wire panel heaters Electrician · 1.00 h/nr | 1 nr | 1 | 1 | 1× electrician @ £30.00/hr blended | £30.00 |
| Dot and dab plasterboard to walls Plasterer · 0.45 h/m2 · min 4h | 27.8 m2 | 12.49 | 18.74 | 1× plasterer @ £30.00/hr + 0.5× labourer @ £30.00/hr blended | £562.05 |
| Board ceiling Plasterer · 0.55 h/m2 · min 4h | 8.16 m2 | 4.49 | 8.98 | 1× plasterer @ £30.00/hr + 1× labourer @ £30.00/hr blended | £269.40 |
| Skim walls and ceilings Plasterer · 0.35 h/m2 · min 4h | 35.9 m2 | 12.57 | 18.86 | 1× plasterer @ £30.00/hr + 0.5× labourer @ £30.00/hr blended | £565.65 |
| Fix skirting Carpenter / joiner · 0.30 h/m · min 2h | 9.20 m | 2.76 | 2.76 | 1× carpenter / joiner @ £30.00/hr blended | £82.80 |
| Mist coat and two coats emulsion to walls and ceilings Decorator · 0.35 h/m2 · min 4h | 35.9 m2 | 12.57 | 12.57 | 1× decorator @ £30.00/hr blended | £377.10 |
| Prime and two coats to woodwork Decorator · 0.20 h/m | 9.20 m | 1.84 | 1.84 | 1× decorator @ £30.00/hr blended | £55.20 |
| Lay laminate flooring and underlay Carpenter / joiner · 0.50 h/m2 · min 3h | 8.16 m2 | 4.08 | 4.08 | 1× carpenter / joiner @ £30.00/hr blended | £122.40 |
| Site set-up, protection, welfare and daily clean General builder · 8.00 h/nr | 1 nr | 8 | 16 | 1× general builder @ £30.00/hr + 1× labourer @ £30.00/hr blended | £480.00 |
BuildLegend platform default v1 — provisional, derived from published UK estimating norms; validate against your own site records.
Measured geometry
| Module | Floor m² | New wall m | Net wall m² | Roof slope m² | Eaves m | Foundation m |
|---|---|---|---|---|---|---|
| Garden room | 8.16 | 14.00 | 27.75 | 16.56 | 16.40 | 14.00 |