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
Wraparound extension
33.6 m² internal · £93,910.80 inc. VAT
£93,910.80
Selling price inc. VAT
£78,259.00
Before VAT
33.6 m²
Internal floor area · £2,327/m²
7 wks
879 person-hours of labour
Cost to selling price
Materials£24,530.70Labour (at cost)£26,368.80Provisional allowances£7,350.00Plant hire£925.00Direct cost£59,174.50Overheads — 10% of direct cost£5,917.45Contingency — 5% of direct cost£2,958.73Profit — 15% markup on cost£10,207.60Rounding to nearest £1.00£0.72Net selling price£78,259.00VAT at 20%£15,651.80Total£93,910.80
Pricing coverage
Cost backed by a price100%— of which verified (your prices)0%— of which catalogue allowances (dated 2026-09-24)43%— of which provisional allowances12.4%Lines missing a price0Stale prices0Assumptions that could move the price1
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 | £210.00 | £480.00 | £0.00 | £690.00 |
| Excavation & foundations | £1,072.50 | £2,444.70 | £0.00 | £3,517.20 |
| Floors | £2,132.00 | £2,421.60 | £0.00 | £4,553.60 |
| Structural elements | £0.00 | £3,840.00 | £6,200.00 | £10,040.00 |
| External walls | £3,682.10 | £3,274.80 | £0.00 | £6,956.90 |
| Roof | £5,252.60 | £5,707.65 | £0.00 | £10,960.25 |
| Windows & external doors | £6,280.00 | £1,380.00 | £0.00 | £7,660.00 |
| Drainage | £546.00 | £1,200.00 | £0.00 | £1,746.00 |
| Plumbing & heating | £613.00 | £648.00 | £0.00 | £1,261.00 |
| Electrical | £294.00 | £714.00 | £0.00 | £1,008.00 |
| Insulation & internal linings | £357.50 | £1,818.30 | £0.00 | £2,175.80 |
| Internal finishes | £311.00 | £2,259.75 | £0.00 | £2,570.75 |
| Scaffold & access | £600.00 | £0.00 | £0.00 | £600.00 |
| Plant hire | £925.00 | £0.00 | £0.00 | £925.00 |
| Waste removal | £3,180.00 | £0.00 | £0.00 | £3,180.00 |
| Deliveries | £0.00 | £0.00 | £250.00 | £250.00 |
| Testing & certification | £0.00 | £180.00 | £0.00 | £180.00 |
| Fees & approvals | £0.00 | £0.00 | £900.00 | £900.00 |
Provisional allowances (4)
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.
- Steel beam and structural design for 1 × 4m opening structural design required£3,100.00A load-bearing opening into the existing house needs a structural engineer's design, a steel beam with padstones and building control sign-off. Allowance covers design and steel supply; the builder's work is priced below.
- Steel beam and structural design for 1 × 4m opening structural design required£3,100.00A load-bearing opening into the existing house needs a structural engineer's design, a steel beam with padstones and building control sign-off. Allowance covers design and steel supply; the builder's work is priced below.
- 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 (18)
- The rear and side parts share one internal junction; no wall is priced between them and the roof is treated as continuous.
- Foundations: trench fill 600mm wide × 1.0m 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 Openings over 2.7m wide may need an engineer-specified lintel or steel; a heavy-duty catalogue lintel has been allowed.
- External walls: facing brick outer skin, 100mm full-fill insulated cavity, 100mm block inner skin.
- 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.
- Drainage: rainwater and any foul water connected to the existing system within 6m, capacity assumed adequate. Building over or near an existing sewer needs the water company's agreement.
- The existing consumer unit has spare capacity for the new circuits; if not, a new unit is extra.
- Heating: 2 radiators added to the existing system; the existing boiler is assumed to have capacity.
- Foundations: trench fill 600mm wide × 1.0m deep in GEN1 concrete under all new external walls.
- Ground floor: 100mm concrete slab on 150mm compacted hardcore with 100mm PIR insulation.
- External walls: facing brick outer skin, 100mm full-fill insulated cavity, 100mm block inner skin.
- 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.
- Drainage: rainwater and any foul water connected to the existing system within 6m, capacity assumed adequate. Building over or near an existing sewer needs the water company's agreement.
- The existing consumer unit has spare capacity for the new circuits; if not, a new unit is extra.
- Heating: 2 radiators added to the existing system; the existing boiler is assumed to have capacity.
- 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 — 64 lines (measured → with waste → purchased)
| Item | Measured | + waste | Buy | Unit price | Cost | Price status |
|---|---|---|---|---|---|---|
| Alloy tower scaffold hire per week access equipment · from access | 4 wk | 4 | 4 × week | £150.00 | £600.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Underground drainage bend 110mm drainage · from drainage | 6 nr | 6 | 6 × each | £6.00 | £36.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Underground drainage pipe 110mm × 3m drainage · from drainage | 12 m | 13.2 | 5 × length | £14.00 | £70.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Bottle gully 110mm drainage · from drainage | 2 nr | 2 | 2 × each | £22.00 | £44.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Inspection chamber 450mm kit with cover drainage · from drainage | 2 nr | 2 | 2 × kit | £120.00 | £240.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Pea gravel 10mm drainage · from drainage | 1.20 m3 | 1.32 | 3 × bulk bag | £52.00 | £156.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| LED downlight (fire-rated, dimmable) electrical · from electrics | 6 nr | 6 | 6 × each | £9.00 | £54.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Socket/switch point: faceplate, back box, cable share electrical · from electrics | 8 nr | 8 | 8 × each | £22.00 | £176.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Mains smoke/heat alarm interlinked electrical · from electrics | 2 nr | 2 | 2 × each | £32.00 | £64.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Ready-mix concrete GEN1 (foundations) excavation foundations · from foundations | 7.77 m3 | 8.16 | 33 × m³ (0.25 m³ steps) | £32.50 | £1,072.50 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Aluminium bi-fold doors 4m wide ×1 external openings · from doors | 4 m | 4 | 4 × m | £820.00 | £3,280.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Flat-roof glass rooflight 1000×1000 external openings · from flat-roof | 3 nr | 3 | 3 × each | £650.00 | £1,950.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| uPVC double-glazed window (A-rated) per m² — 1.2×1.2m ×2 external openings · from windows | 2.88 m2 | 2.88 | 3 × m² | £350.00 | £1,050.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Concrete block 100mm 7.3N external walls · from below-dpc, cavity-wall | 516.2 nr | 542.0 | 8 × pack of 72 | £130.00 | £1,040.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Building sand external walls · from below-dpc, cavity-wall | 1.83 m3 | 2.02 | 5 × bulk bag | £52.00 | £260.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Full-fill cavity insulation 100mm external walls · from cavity-wall | 35.0 m2 | 37.6 | 9 × pack | £30.00 | £270.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Insulated cavity closer 2.4m external walls · from cavity-wall | 15.4 m | 15.4 | 7 × length | £6.00 | £42.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Cement 25kg external walls · from below-dpc, cavity-wall | 16.7 bag | 18.4 | 19 × bag | £6.50 | £123.50 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| DPC 100mm × 30m external walls · from cavity-wall | 37 m | 42.5 | 2 × roll | £9.00 | £18.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Facing brick (standard 65mm) external walls · from cavity-wall | 2098.2 nr | 2203.1 | 5 × pack of 500 | £300.00 | £1,500.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Steel cavity lintel 1800mm over window external walls · from cavity-wall | 2 nr | 2 | 2 × each | £75.00 | £150.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Steel cavity lintel 3600mm (heavy duty) over bifold external walls · from cavity-wall | 1 nr | 1 | 1 × each | £240.00 | £240.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Stainless wall ties 225mm external walls · from cavity-wall | 104.9 nr | 104.9 | 1 × box of 250 | £35.00 | £35.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Weep vent external walls · from cavity-wall | 9 nr | 9 | 9 × each | £0.40 | £3.60 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Damp-proof membrane 1200 gauge 4m × 25m floors · from slab | 33.6 m2 | 38.7 | 1 × roll | £45.00 | £45.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| MOT Type 1 sub-base 150mm compacted floors · from slab | 6.56 m3 | 7.21 | 15 × bulk bag | £48.00 | £720.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Reinforcement mesh A142 4.8m × 2.4m floors · from slab | 33.6 m2 | 38.7 | 4 × sheet | £32.00 | £128.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| PIR floor insulation 100mm floors · from slab | 33.6 m2 | 36.2 | 13 × sheet | £38.00 | £494.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Ready-mix concrete GEN3 100mm slab floors · from slab | 3.36 m3 | 3.53 | 15 × m³ (0.25 m³ steps) | £35.00 | £525.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Sand blinding 50mm floors · from slab | 1.68 m3 | 1.85 | 4 × bulk bag | £55.00 | £220.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Drywall adhesive 25kg (dot and dab) insulation linings · from linings | 35.0 m2 | 36.7 | 13 × bag | £8.00 | £104.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Drywall screws 38mm box of 1000 insulation linings · from ceiling | 1008.9 nr | 1008.9 | 2 × box | £12.00 | £24.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Plasterboard 12.5mm 2400×1200 insulation linings · from linings, ceiling | 68.6 m2 | 75.5 | 27 × sheet | £8.50 | £229.50 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Angle beads to reveals internal finishes · from skim | 15.4 m | 15.4 | 7 × length | £2.00 | £14.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Emulsion paint 10L (mist + two coats ≈ 60 m²) internal finishes · from decorating | 68.6 m2 | 68.6 | 2 × tub | £32.00 | £64.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Multi-finish plaster 25kg internal finishes · from skim | 68.6 m2 | 72.0 | 8 × bag | £9.50 | £76.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Satinwood 2.5L (≈ 20 m of skirting/architrave) internal finishes · from decorating | 30.6 m | 30.6 | 2 × tin | £28.00 | £56.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Scrim tape 90m internal finishes · from skim | 82.3 m | 82.3 | 1 × roll | £5.00 | £5.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| MDF skirting 145mm × 4.4m internal finishes · from skirting | 30.6 m | 33.7 | 8 × length | £12.00 | £96.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Acrow props & strongboys (set) per week plant · from knock-through | 2 wk | 2 | 2 × week | £60.00 | £120.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| 1t dumper hire per day plant · from foundations | 2 day | 2 | 2 × day | £70.00 | £140.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| 1.5t mini digger hire per day plant · from foundations | 2 day | 2 | 2 × day | £95.00 | £190.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Cement mixer hire per week plant · from prelims | 7 wk | 7 | 7 × week | £45.00 | £315.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Plant delivery/collection plant · from foundations | 2 nr | 2 | 2 × each | £80.00 | £160.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Push-fit fittings per radiator/appliance plumbing heating · from radiators | 4 nr | 4 | 4 × set | £18.00 | £72.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Plastic push-fit pipe 15mm 50m coil plumbing heating · from radiators | 32 m | 35.2 | 1 × coil | £45.00 | £45.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Double panel radiator 600×1000 with TRV & valves plumbing heating · from radiators | 4 nr | 4 | 4 × each | £124.00 | £496.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Site toilet hire per week preliminaries · from prelims | 7 wk | 7 | 7 × week | £30.00 | £210.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Flat roof joists C24 47×195 @ 400 centres roof · from flat-roof | 127.0 m | 139.8 | 140 × m | £4.60 | £644.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| uPVC downpipe 68mm × 2.5m with clips & shoe roof · from flat-roof | 3 nr | 3 | 3 × each | £18.00 | £54.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| EPDM rubber roof membrane with adhesives & trims roof · from flat-roof | 55.9 m2 | 64.3 | 65 × m² | £16.00 | £1,040.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| uPVC fascia board 175mm × 5m roof · from flat-roof | 23.3 m | 25.6 | 6 × length | £32.00 | £192.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Firring strips (tapered) per m roof · from flat-roof | 127.0 m | 139.8 | 140 × m | £2.00 | £280.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Lead/lead-free abutment flashing with cavity tray per m roof · from flat-roof | 18.5 m | 18.5 | 19 × m | £28.00 | £532.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| uPVC half-round gutter 112mm × 4m roof · from flat-roof | 23.3 m | 25.6 | 7 × length | £14.00 | £98.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Gutter bracket roof · from flat-roof | 23.3 nr | 23.3 | 24 × each | £1.30 | £31.20 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Gutter fittings (outlet, stop ends, unions) per run roof · from flat-roof | 4 nr | 4 | 4 × set | £25.00 | £100.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| OSB3 18mm 2440×1220 roof · from flat-roof | 101.6 m2 | 111.8 | 38 × sheet | £28.00 | £1,064.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Warm roof PIR insulation 120mm roof · from flat-roof | 50.8 m2 | 54.6 | 19 × sheet | £45.00 | £855.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| uPVC soffit board 300mm × 5m roof · from flat-roof | 23.3 m | 25.6 | 6 × length | £30.00 | £180.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Vapour control layer 50m² roof · from flat-roof | 50.8 m2 | 58.4 | 2 × roll | £42.00 | £84.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Wall plate 100×50 treated roof · from flat-roof | 37 m | 40.7 | 41 × m | £2.40 | £98.40 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| Muck-away of excavated spoil (grab lorry) waste · from foundations | 5 nr | 5 | 5 × load | £380.00 | £1,900.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
| 8-yard skip (mixed waste) waste · from knock-through, waste | 4 nr | 4 | 4 × each | £320.00 | £1,280.00 | Catalogue allowance BuildLegend catalogue · 2026-09-24 |
Labour — 56 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 | 12 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 | 4.20 m3 | 4 | 8 | 2× groundworker @ £30.00/hr blended | £240.00 |
| Blockwork below DPC Bricklayer · 0.70 h/m2 | 9 m2 | 6.3 | 9.45 | 1× bricklayer @ £30.00/hr + 0.5× labourer @ £30.00/hr blended | £283.50 |
| Hardcore, blind, DPM, insulation, mesh and pour slab Groundworker · 1.20 h/m2 · min 8h | 21.1 m2 | 25.31 | 50.62 | 2× groundworker @ £30.00/hr blended | £1,518.60 |
| Facing brickwork outer skin Bricklayer · 1.20 h/m2 · min 8h | 16.6 m2 | 19.92 | 29.88 | 1× bricklayer @ £30.00/hr + 0.5× labourer @ £30.00/hr blended | £896.40 |
| Blockwork inner skin Bricklayer · 0.70 h/m2 · min 8h | 16.6 m2 | 11.62 | 17.43 | 1× bricklayer @ £30.00/hr + 0.5× labourer @ £30.00/hr blended | £522.90 |
| Wall ties, cavity insulation and closers Bricklayer · 0.10 h/m2 | 16.6 m2 | 1.66 | 1.66 | 1× bricklayer @ £30.00/hr blended | £49.80 |
| Bed lintels Bricklayer · 1.00 h/nr | 1 nr | 1 | 2 | 1× bricklayer @ £30.00/hr + 1× labourer @ £30.00/hr blended | £60.00 |
| Flat roof joists, firrings and deck Carpenter / joiner · 0.90 h/m2 · min 8h | 30.4 m2 | 27.32 | 54.64 | 2× carpenter / joiner @ £30.00/hr blended | £1,639.20 |
| Vapour control layer, insulation and upper deck Carpenter / joiner · 0.30 h/m2 | 30.4 m2 | 9.11 | 18.22 | 2× carpenter / joiner @ £30.00/hr blended | £546.60 |
| Lay epdm rubber roof membrane with adhesives & trims Roofer · 0.50 h/m2 · min 6h | 30.4 m2 | 15.18 | 30.36 | 2× roofer @ £30.00/hr blended | £910.80 |
| Fascia, soffit, guttering and downpipes Carpenter / joiner · 0.50 h/m · min 4h | 12.4 m | 6.2 | 9.3 | 1× carpenter / joiner @ £30.00/hr + 0.5× labourer @ £30.00/hr blended | £279.00 |
| Fit rooflights and flashings Roofer · 4.00 h/nr | 3 nr | 12 | 24 | 1× roofer @ £30.00/hr + 1× carpenter / joiner @ £30.00/hr blended | £720.00 |
| 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 |
| Excavate, lay and backfill drainage run to the existing system Groundworker · 1.00 h/m · min 6h | 6 m | 6 | 12 | 2× groundworker @ £30.00/hr blended | £360.00 |
| Install inspection chamber and connect to existing drain Groundworker · 4.00 h/nr | 1 nr | 4 | 8 | 2× groundworker @ £30.00/hr blended | £240.00 |
| Builder's work: needle, prop, remove wall, set steel, make good General builder · 32.00 h/nr | 1 nr | 32 | 64 | 2× general builder @ £30.00/hr blended | £1,920.00 |
| Electrical first fix: cables, back boxes, circuits Electrician · 1.10 h/nr · min 4h | 9 nr | 9.9 | 9.9 | 1× electrician @ £30.00/hr blended | £297.00 |
| Electrical second fix: faceplates, fittings, connection Electrician · 0.60 h/nr · min 3h | 9 nr | 5.4 | 5.4 | 1× electrician @ £30.00/hr blended | £162.00 |
| Test, certify and notify (Part P / equivalent) Electrician · 3.00 h/nr | 1 nr | 3 | 3 | 1× electrician @ £30.00/hr blended | £90.00 |
| Heating first fix: run pipework from existing system Plumber / heating engineer · 0.30 h/m · min 4h | 16 m | 4.8 | 4.8 | 1× plumber / heating engineer @ £30.00/hr blended | £144.00 |
| Hang radiators, connect, balance and test Plumber / heating engineer · 3.00 h/nr | 2 nr | 6 | 6 | 1× plumber / heating engineer @ £30.00/hr blended | £180.00 |
| Dot and dab plasterboard to walls Plasterer · 0.45 h/m2 · min 4h | 16.6 m2 | 7.47 | 11.21 | 1× plasterer @ £30.00/hr + 0.5× labourer @ £30.00/hr blended | £336.15 |
| Board ceiling Plasterer · 0.55 h/m2 · min 4h | 21.1 m2 | 11.6 | 23.2 | 1× plasterer @ £30.00/hr + 1× labourer @ £30.00/hr blended | £696.00 |
| Skim walls and ceilings Plasterer · 0.35 h/m2 · min 4h | 37.7 m2 | 13.19 | 19.79 | 1× plasterer @ £30.00/hr + 0.5× labourer @ £30.00/hr blended | £593.55 |
| Fix skirting Carpenter / joiner · 0.30 h/m · min 2h | 14.8 m | 4.44 | 4.44 | 1× carpenter / joiner @ £30.00/hr blended | £133.20 |
| Mist coat and two coats emulsion to walls and ceilings Decorator · 0.35 h/m2 · min 4h | 37.7 m2 | 13.19 | 13.19 | 1× decorator @ £30.00/hr blended | £395.70 |
| Prime and two coats to woodwork Decorator · 0.20 h/m | 14.8 m | 2.96 | 2.96 | 1× decorator @ £30.00/hr blended | £88.80 |
| Excavate trenches and reduced level (machine) Groundworker · 0.60 h/m3 · min 8h · +4h setup | 8.85 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 | 3.57 m3 | 4 | 8 | 2× groundworker @ £30.00/hr blended | £240.00 |
| Blockwork below DPC Bricklayer · 0.70 h/m2 | 7.65 m2 | 5.36 | 8.04 | 1× bricklayer @ £30.00/hr + 0.5× labourer @ £30.00/hr blended | £241.20 |
| Hardcore, blind, DPM, insulation, mesh and pour slab Groundworker · 1.20 h/m2 · min 8h | 12.5 m2 | 15.05 | 30.1 | 2× groundworker @ £30.00/hr blended | £903.00 |
| Facing brickwork outer skin Bricklayer · 1.20 h/m2 · min 8h | 18.4 m2 | 22.04 | 33.06 | 1× bricklayer @ £30.00/hr + 0.5× labourer @ £30.00/hr blended | £991.80 |
| Blockwork inner skin Bricklayer · 0.70 h/m2 · min 8h | 18.4 m2 | 12.86 | 19.29 | 1× bricklayer @ £30.00/hr + 0.5× labourer @ £30.00/hr blended | £578.70 |
| Wall ties, cavity insulation and closers Bricklayer · 0.10 h/m2 | 18.4 m2 | 1.84 | 1.84 | 1× bricklayer @ £30.00/hr blended | £55.20 |
| 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 | 20.5 m2 | 18.41 | 36.82 | 2× carpenter / joiner @ £30.00/hr blended | £1,104.60 |
| Vapour control layer, insulation and upper deck Carpenter / joiner · 0.30 h/m2 | 20.5 m2 | 6.14 | 12.28 | 2× carpenter / joiner @ £30.00/hr blended | £368.40 |
| Lay epdm rubber roof membrane with adhesives & trims Roofer · 0.50 h/m2 · min 6h | 20.5 m2 | 10.23 | 20.46 | 2× roofer @ £30.00/hr blended | £613.80 |
| Fascia, soffit, guttering and downpipes Carpenter / joiner · 0.50 h/m · min 4h | 10.9 m | 5.45 | 8.18 | 1× carpenter / joiner @ £30.00/hr + 0.5× labourer @ £30.00/hr blended | £245.25 |
| Fit windows, seal and make good Carpenter / joiner · 2.50 h/nr | 2 nr | 5 | 10 | 2× carpenter / joiner @ £30.00/hr blended | £300.00 |
| Excavate, lay and backfill drainage run to the existing system Groundworker · 1.00 h/m · min 6h | 6 m | 6 | 12 | 2× groundworker @ £30.00/hr blended | £360.00 |
| Install inspection chamber and connect to existing drain Groundworker · 4.00 h/nr | 1 nr | 4 | 8 | 2× groundworker @ £30.00/hr blended | £240.00 |
| Builder's work: needle, prop, remove wall, set steel, make good General builder · 32.00 h/nr | 1 nr | 32 | 64 | 2× general builder @ £30.00/hr blended | £1,920.00 |
| Electrical first fix: cables, back boxes, circuits Electrician · 1.10 h/nr · min 4h | 5 nr | 5.5 | 5.5 | 1× electrician @ £30.00/hr blended | £165.00 |
| Electrical second fix: faceplates, fittings, connection Electrician · 0.60 h/nr · min 3h | 5 nr | 3 | 3 | 1× electrician @ £30.00/hr blended | £90.00 |
| Test, certify and notify (Part P / equivalent) Electrician · 3.00 h/nr | 1 nr | 3 | 3 | 1× electrician @ £30.00/hr blended | £90.00 |
| Heating first fix: run pipework from existing system Plumber / heating engineer · 0.30 h/m · min 4h | 16 m | 4.8 | 4.8 | 1× plumber / heating engineer @ £30.00/hr blended | £144.00 |
| Hang radiators, connect, balance and test Plumber / heating engineer · 3.00 h/nr | 2 nr | 6 | 6 | 1× plumber / heating engineer @ £30.00/hr blended | £180.00 |
| Dot and dab plasterboard to walls Plasterer · 0.45 h/m2 · min 4h | 18.4 m2 | 8.27 | 12.41 | 1× plasterer @ £30.00/hr + 0.5× labourer @ £30.00/hr blended | £372.15 |
| Board ceiling Plasterer · 0.55 h/m2 · min 4h | 12.5 m2 | 6.9 | 13.8 | 1× plasterer @ £30.00/hr + 1× labourer @ £30.00/hr blended | £414.00 |
| Skim walls and ceilings Plasterer · 0.35 h/m2 · min 4h | 30.9 m2 | 10.82 | 16.23 | 1× plasterer @ £30.00/hr + 0.5× labourer @ £30.00/hr blended | £486.90 |
| Fix skirting Carpenter / joiner · 0.30 h/m · min 2h | 15.8 m | 4.74 | 4.74 | 1× carpenter / joiner @ £30.00/hr blended | £142.20 |
| Mist coat and two coats emulsion to walls and ceilings Decorator · 0.35 h/m2 · min 4h | 30.9 m2 | 10.82 | 10.82 | 1× decorator @ £30.00/hr blended | £324.60 |
| Prime and two coats to woodwork Decorator · 0.20 h/m | 15.8 m | 3.16 | 3.16 | 1× decorator @ £30.00/hr blended | £94.80 |
| 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 |
|---|---|---|---|---|---|---|
| Rear extension | 21.09 | 10.00 | 16.60 | 30.36 | 12.40 | 10.00 |
| Side return | 12.54 | 8.50 | 18.37 | 20.46 | 10.90 | 8.50 |