{
 "name": "Estiquote UK Renovation Cost Model",
 "version": "2026-Q3",
 "reviewed": "2026-09-25",
 "nextReview": "2026-12",
 "currency": "GBP",
 "basis": "Planning ranges for a typical UK home outside London, excluding VAT, before regional adjustment. Displayed prices add VAT at the project's rate.",
 "contingency": 0.15,
 "escalationPerYear": 0.03,
 "finishes": {
  "budget": "Budget",
  "mid": "Mid-range",
  "premium": "Premium"
 },
 "regions": [
  {
   "id": "uk",
   "name": "UK average (outside London)",
   "factor": 1.0
  },
  {
   "id": "london",
   "name": "London",
   "factor": 1.35
  },
  {
   "id": "south-east",
   "name": "South East",
   "factor": 1.15
  },
  {
   "id": "east",
   "name": "East of England",
   "factor": 1.07
  },
  {
   "id": "south-west",
   "name": "South West",
   "factor": 1.04
  },
  {
   "id": "west-midlands",
   "name": "West Midlands",
   "factor": 0.97
  },
  {
   "id": "east-midlands",
   "name": "East Midlands",
   "factor": 0.95
  },
  {
   "id": "scotland",
   "name": "Scotland",
   "factor": 0.95
  },
  {
   "id": "north-west",
   "name": "North West",
   "factor": 0.93
  },
  {
   "id": "yorkshire",
   "name": "Yorkshire and the Humber",
   "factor": 0.92
  },
  {
   "id": "wales",
   "name": "Wales",
   "factor": 0.9
  },
  {
   "id": "north-east",
   "name": "North East",
   "factor": 0.88
  },
  {
   "id": "northern-ireland",
   "name": "Northern Ireland",
   "factor": 0.82
  }
 ],
 "postcodeAreas": {
  "E": "london",
  "EC": "london",
  "N": "london",
  "NW": "london",
  "SE": "london",
  "SW": "london",
  "W": "london",
  "WC": "london",
  "BR": "london",
  "CR": "london",
  "HA": "london",
  "IG": "london",
  "SM": "london",
  "UB": "london",
  "BN": "south-east",
  "CT": "south-east",
  "GU": "south-east",
  "ME": "south-east",
  "MK": "south-east",
  "OX": "south-east",
  "PO": "south-east",
  "RG": "south-east",
  "RH": "south-east",
  "SL": "south-east",
  "SO": "south-east",
  "TN": "south-east",
  "KT": "south-east",
  "TW": "south-east",
  "DA": "south-east",
  "HP": "south-east",
  "AL": "east",
  "CB": "east",
  "CM": "east",
  "CO": "east",
  "EN": "east",
  "IP": "east",
  "LU": "east",
  "NR": "east",
  "PE": "east",
  "RM": "east",
  "SG": "east",
  "SS": "east",
  "WD": "east",
  "BA": "south-west",
  "BH": "south-west",
  "BS": "south-west",
  "DT": "south-west",
  "EX": "south-west",
  "GL": "south-west",
  "PL": "south-west",
  "SN": "south-west",
  "SP": "south-west",
  "TA": "south-west",
  "TQ": "south-west",
  "TR": "south-west",
  "B": "west-midlands",
  "CV": "west-midlands",
  "DY": "west-midlands",
  "HR": "west-midlands",
  "ST": "west-midlands",
  "SY": "west-midlands",
  "TF": "west-midlands",
  "WR": "west-midlands",
  "WS": "west-midlands",
  "WV": "west-midlands",
  "DE": "east-midlands",
  "LE": "east-midlands",
  "LN": "east-midlands",
  "NG": "east-midlands",
  "NN": "east-midlands",
  "BD": "yorkshire",
  "DN": "yorkshire",
  "HD": "yorkshire",
  "HG": "yorkshire",
  "HU": "yorkshire",
  "HX": "yorkshire",
  "LS": "yorkshire",
  "S": "yorkshire",
  "WF": "yorkshire",
  "YO": "yorkshire",
  "BB": "north-west",
  "BL": "north-west",
  "CA": "north-west",
  "CH": "north-west",
  "CW": "north-west",
  "FY": "north-west",
  "L": "north-west",
  "LA": "north-west",
  "M": "north-west",
  "OL": "north-west",
  "PR": "north-west",
  "SK": "north-west",
  "WA": "north-west",
  "WN": "north-west",
  "DH": "north-east",
  "DL": "north-east",
  "NE": "north-east",
  "SR": "north-east",
  "TS": "north-east",
  "CF": "wales",
  "LD": "wales",
  "LL": "wales",
  "NP": "wales",
  "SA": "wales",
  "AB": "scotland",
  "DD": "scotland",
  "DG": "scotland",
  "EH": "scotland",
  "FK": "scotland",
  "G": "scotland",
  "HS": "scotland",
  "IV": "scotland",
  "KA": "scotland",
  "KW": "scotland",
  "KY": "scotland",
  "ML": "scotland",
  "PA": "scotland",
  "PH": "scotland",
  "TD": "scotland",
  "ZE": "scotland",
  "BT": "northern-ireland"
 },
 "postcodeDistricts": {
  "EN1": "london",
  "EN2": "london",
  "EN3": "london",
  "EN4": "london",
  "EN5": "london",
  "KT1": "london",
  "KT2": "london",
  "KT3": "london",
  "KT4": "london",
  "KT5": "london",
  "KT6": "london",
  "KT9": "london",
  "TW1": "london",
  "TW2": "london",
  "TW3": "london",
  "TW4": "london",
  "TW5": "london",
  "TW6": "london",
  "TW7": "london",
  "TW8": "london",
  "TW9": "london",
  "TW10": "london",
  "TW11": "london",
  "TW12": "london",
  "TW13": "london",
  "TW14": "london",
  "RM1": "london",
  "RM2": "london",
  "RM3": "london",
  "RM4": "london",
  "RM5": "london",
  "RM6": "london",
  "RM7": "london",
  "RM8": "london",
  "RM9": "london",
  "RM10": "london",
  "RM11": "london",
  "RM12": "london",
  "RM13": "london",
  "RM14": "london",
  "DA5": "london",
  "DA6": "london",
  "DA7": "london",
  "DA8": "london",
  "DA14": "london",
  "DA15": "london",
  "DA16": "london",
  "DA17": "london",
  "DA18": "london",
  "CR3": "south-east",
  "CR6": "south-east",
  "BR8": "south-east",
  "IG7": "east",
  "IG10": "east",
  "SM7": "south-east",
  "HP1": "east",
  "HP2": "east",
  "HP3": "east",
  "HP4": "east",
  "HP23": "east",
  "MK40": "east",
  "MK41": "east",
  "MK42": "east",
  "MK43": "east",
  "MK44": "east",
  "MK45": "east",
  "PE9": "east-midlands",
  "PE10": "east-midlands",
  "PE11": "east-midlands",
  "PE12": "east-midlands",
  "PE20": "east-midlands",
  "PE21": "east-midlands",
  "PE22": "east-midlands",
  "PE23": "east-midlands",
  "PE24": "east-midlands",
  "PE25": "east-midlands",
  "SP10": "south-east",
  "SP11": "south-east",
  "SY15": "wales",
  "SY16": "wales",
  "SY17": "wales",
  "SY18": "wales",
  "SY19": "wales",
  "SY20": "wales",
  "SY21": "wales",
  "SY22": "wales",
  "SY23": "wales",
  "SY24": "wales",
  "SY25": "wales",
  "CH5": "wales",
  "CH6": "wales",
  "CH7": "wales",
  "CH8": "wales",
  "SK13": "east-midlands",
  "SK17": "east-midlands",
  "SK22": "east-midlands",
  "SK23": "east-midlands",
  "S40": "east-midlands",
  "S41": "east-midlands",
  "S42": "east-midlands",
  "S43": "east-midlands",
  "S44": "east-midlands",
  "S45": "east-midlands",
  "S80": "east-midlands",
  "S81": "east-midlands",
  "TD15": "north-east"
 },
 "projects": [
  {
   "id": "extension",
   "name": "House extension",
   "short": "Extension",
   "page": "/costs/house-extension/",
   "vat": 0.2,
   "regionSensitivity": 1.0,
   "question": "What type of extension?",
   "variants": [
    {
     "id": "single-storey",
     "name": "Single-storey rear",
     "basis": "per_m2",
     "defaultSize": 25,
     "presets": [
      15,
      25,
      40
     ],
     "min": 6,
     "max": 150,
     "smallBelow": 15,
     "rates": {
      "budget": [
       1700,
       2100
      ],
      "mid": [
       2100,
       2600
      ],
      "premium": [
       2700,
       3300
      ]
     },
     "fees": "extension-small",
     "sources": [
      "checkatrade-extension",
      "fmb-single",
      "hr-extension",
      "buildit-extension",
      "mjq-extension"
     ]
    },
    {
     "id": "double-storey",
     "name": "Double-storey",
     "basis": "per_m2",
     "defaultSize": 40,
     "presets": [
      30,
      40,
      60
     ],
     "min": 12,
     "max": 200,
     "smallBelow": 20,
     "sizeNote": "total new floor area over both storeys",
     "rates": {
      "budget": [
       1500,
       1900
      ],
      "mid": [
       1900,
       2400
      ],
      "premium": [
       2500,
       3100
      ]
     },
     "fees": "extension-large",
     "sources": [
      "checkatrade-extension",
      "fmb-double",
      "hr-extension",
      "buildit-extension"
     ]
    },
    {
     "id": "wraparound",
     "name": "Wraparound or side return",
     "basis": "per_m2",
     "defaultSize": 30,
     "presets": [
      20,
      30,
      45
     ],
     "min": 8,
     "max": 120,
     "smallBelow": 15,
     "rates": {
      "budget": [
       1900,
       2300
      ],
      "mid": [
       2300,
       2900
      ],
      "premium": [
       3000,
       3700
      ]
     },
     "fees": "extension-small",
     "sources": [
      "checkatrade-side-return",
      "harper-wrap",
      "hr-extension",
      "buildit-extension"
     ]
    }
   ],
   "addOns": [
    {
     "id": "kitchen",
     "name": "Include a new kitchen in the extension",
     "ratesFrom": "kitchen/fitted",
     "regionSensitivity": 0.5
    }
   ],
   "sizeLabel": "Floor area",
   "unit": "m²",
   "headline": "single-storey"
  },
  {
   "id": "loft",
   "name": "Loft conversion",
   "short": "Loft",
   "page": "/costs/loft-conversion/",
   "vat": 0.2,
   "regionSensitivity": 1.0,
   "question": "What type of loft conversion?",
   "variants": [
    {
     "id": "rooflight",
     "name": "Rooflight (Velux)",
     "basis": "scaled_total",
     "baseSize": 30,
     "exponent": 0.6,
     "defaultSize": 30,
     "presets": [
      20,
      30,
      40
     ],
     "min": 12,
     "max": 60,
     "rates": {
      "budget": [
       22000,
       27000
      ],
      "mid": [
       27000,
       35000
      ],
      "premium": [
       35000,
       45000
      ]
     },
     "fees": "loft",
     "sources": [
      "checkatrade-loft",
      "hr-loft",
      "fmb-loft",
      "mjq-loft"
     ]
    },
    {
     "id": "dormer",
     "name": "Rear dormer",
     "basis": "scaled_total",
     "baseSize": 30,
     "exponent": 0.6,
     "defaultSize": 30,
     "presets": [
      20,
      30,
      40
     ],
     "min": 12,
     "max": 60,
     "rates": {
      "budget": [
       40000,
       47000
      ],
      "mid": [
       47000,
       58000
      ],
      "premium": [
       58000,
       75000
      ]
     },
     "fees": "loft",
     "sources": [
      "checkatrade-loft",
      "hr-loft",
      "fmb-loft",
      "mjq-loft"
     ]
    },
    {
     "id": "hip-to-gable",
     "name": "Hip-to-gable (with rear dormer)",
     "basis": "scaled_total",
     "baseSize": 30,
     "exponent": 0.6,
     "defaultSize": 30,
     "presets": [
      20,
      30,
      40
     ],
     "min": 12,
     "max": 60,
     "rates": {
      "budget": [
       48000,
       55000
      ],
      "mid": [
       55000,
       68000
      ],
      "premium": [
       68000,
       85000
      ]
     },
     "fees": "loft",
     "sources": [
      "checkatrade-loft",
      "hr-loft",
      "fmb-loft",
      "mjq-loft"
     ]
    },
    {
     "id": "mansard",
     "name": "Mansard",
     "basis": "scaled_total",
     "baseSize": 30,
     "exponent": 0.6,
     "defaultSize": 30,
     "presets": [
      20,
      30,
      40
     ],
     "min": 12,
     "max": 60,
     "rates": {
      "budget": [
       55000,
       65000
      ],
      "mid": [
       65000,
       85000
      ],
      "premium": [
       85000,
       120000
      ]
     },
     "fees": "loft",
     "sources": [
      "checkatrade-loft",
      "hr-loft",
      "fmb-loft",
      "mjq-loft"
     ]
    }
   ],
   "sizeLabel": "New floor area",
   "unit": "m²",
   "headline": "dormer"
  },
  {
   "id": "kitchen",
   "name": "New kitchen",
   "short": "Kitchen",
   "page": "/costs/kitchen/",
   "vat": 0.2,
   "regionSensitivity": 0.5,
   "question": "What size of kitchen?",
   "variants": [
    {
     "id": "fitted",
     "name": "Supply and fit",
     "basis": "sized_total",
     "sizes": [
      {
       "id": "small",
       "name": "Small (galley or up to 8 units)",
       "factor": 0.8
      },
      {
       "id": "medium",
       "name": "Medium (typical 3-bed house)",
       "factor": 1.0
      },
      {
       "id": "large",
       "name": "Large (kitchen-diner or island)",
       "factor": 1.3
      }
     ],
     "defaultSizeId": "medium",
     "rates": {
      "budget": [
       4170,
       6670
      ],
      "mid": [
       7500,
       13330
      ],
      "premium": [
       16670,
       33330
      ]
     },
     "sources": [
      "checkatrade-kitchen",
      "mjq-kitchen",
      "mybuilder-kitchen",
      "checkatrade-kitchen-fitting"
     ]
    }
   ],
   "headline": "fitted"
  },
  {
   "id": "bathroom",
   "name": "Bathroom",
   "short": "Bathroom",
   "page": "/costs/bathroom/",
   "vat": 0.2,
   "regionSensitivity": 0.6,
   "question": "What kind of bathroom work?",
   "variants": [
    {
     "id": "refit",
     "name": "Full bathroom refit, same layout",
     "basis": "total",
     "rates": {
      "budget": [
       3330,
       4580
      ],
      "mid": [
       5000,
       7500
      ],
      "premium": [
       9170,
       13330
      ]
     },
     "sources": [
      "checkatrade-bathroom",
      "mjq-bathroom"
     ]
    },
    {
     "id": "ensuite",
     "name": "New en-suite",
     "basis": "total",
     "rates": {
      "budget": [
       3750,
       5000
      ],
      "mid": [
       5000,
       7500
      ],
      "premium": [
       8330,
       12500
      ]
     },
     "sources": [
      "checkatrade-ensuite",
      "fmb-loft"
     ]
    },
    {
     "id": "wet-room",
     "name": "Wet room",
     "basis": "total",
     "rates": {
      "budget": [
       4170,
       5420
      ],
      "mid": [
       5420,
       7920
      ],
      "premium": [
       8330,
       11670
      ]
     },
     "sources": [
      "checkatrade-wetroom",
      "mjq-wetroom"
     ]
    },
    {
     "id": "downstairs-wc",
     "name": "Downstairs toilet",
     "basis": "total",
     "rates": {
      "budget": [
       1670,
       2330
      ],
      "mid": [
       2330,
       3330
      ],
      "premium": [
       3330,
       5000
      ]
     },
     "sources": [
      "checkatrade-wc",
      "mybuilder-wc"
     ]
    }
   ],
   "headline": "refit"
  },
  {
   "id": "garage",
   "name": "Garage conversion",
   "short": "Garage conversion",
   "page": "/costs/garage-conversion/",
   "vat": 0.2,
   "regionSensitivity": 1.0,
   "question": "What kind of garage?",
   "variants": [
    {
     "id": "integral",
     "name": "Integral or attached single garage",
     "basis": "total",
     "rates": {
      "budget": [
       9000,
       12000
      ],
      "mid": [
       12000,
       17000
      ],
      "premium": [
       17000,
       25000
      ]
     },
     "fees": "garage",
     "sources": [
      "checkatrade-garage",
      "fmb-garage",
      "mybuilder-garage"
     ]
    },
    {
     "id": "detached",
     "name": "Detached single garage",
     "basis": "total",
     "rates": {
      "budget": [
       15000,
       18000
      ],
      "mid": [
       18000,
       25000
      ],
      "premium": [
       25000,
       35000
      ]
     },
     "fees": "garage",
     "sources": [
      "checkatrade-garage"
     ]
    }
   ],
   "headline": "integral"
  },
  {
   "id": "renovation",
   "name": "Whole-house renovation",
   "short": "Renovation",
   "page": "/costs/house-renovation/",
   "vat": 0.2,
   "regionSensitivity": 1.0,
   "question": "What scope?",
   "variants": [
    {
     "id": "full",
     "name": "Full renovation (rewire, heating, kitchen, bathroom, plaster)",
     "basis": "per_m2",
     "defaultSize": 90,
     "presets": [
      60,
      90,
      130
     ],
     "min": 30,
     "max": 400,
     "rates": {
      "budget": [
       550,
       800
      ],
      "mid": [
       800,
       1200
      ],
      "premium": [
       1200,
       2000
      ]
     },
     "sources": [
      "checkatrade-renovation",
      "mybuilder-renovation"
     ]
    }
   ],
   "sizeLabel": "Internal floor area",
   "unit": "m²",
   "headline": "full"
  },
  {
   "id": "new-build",
   "name": "New build house",
   "short": "New build",
   "page": "/costs/new-build/",
   "vat": 0.0,
   "regionSensitivity": 1.0,
   "question": "Build route",
   "variants": [
    {
     "id": "contractor",
     "name": "Built by a main contractor",
     "basis": "per_m2",
     "defaultSize": 140,
     "presets": [
      100,
      140,
      200
     ],
     "min": 50,
     "max": 600,
     "rates": {
      "budget": [
       1800,
       2300
      ],
      "mid": [
       2300,
       2900
      ],
      "premium": [
       3000,
       4000
      ]
     },
     "sources": [
      "buildit-house",
      "hr-house",
      "checkatrade-house"
     ]
    }
   ],
   "sizeLabel": "Gross internal floor area",
   "unit": "m²",
   "headline": "contractor"
  },
  {
   "id": "rewire",
   "name": "House rewire",
   "short": "Rewire",
   "page": "/costs/rewiring/",
   "vat": 0.2,
   "regionSensitivity": 0.8,
   "question": "Property size",
   "finishNames": {
    "budget": "Basic",
    "mid": "Standard",
    "premium": "Extra circuits"
   },
   "variants": [
    {
     "id": "flat-1",
     "name": "1-bed flat",
     "basis": "total",
     "rates": {
      "budget": [
       2500,
       2750
      ],
      "mid": [
       2750,
       3500
      ],
      "premium": [
       3500,
       4000
      ]
     },
     "sources": [
      "checkatrade-rewire",
      "mybuilder-rewire",
      "mjq-rewire"
     ]
    },
    {
     "id": "house-2",
     "name": "2-bed house",
     "basis": "total",
     "rates": {
      "budget": [
       3170,
       3540
      ],
      "mid": [
       3540,
       4380
      ],
      "premium": [
       4380,
       4830
      ]
     },
     "sources": [
      "mybuilder-rewire",
      "mjq-rewire"
     ]
    },
    {
     "id": "house-3",
     "name": "3-bed house",
     "basis": "total",
     "rates": {
      "budget": [
       3750,
       4500
      ],
      "mid": [
       4500,
       5960
      ],
      "premium": [
       5960,
       6670
      ]
     },
     "sources": [
      "checkatrade-rewire",
      "mybuilder-rewire",
      "mjq-rewire"
     ]
    },
    {
     "id": "house-4",
     "name": "4-bed house",
     "basis": "total",
     "rates": {
      "budget": [
       5000,
       5880
      ],
      "mid": [
       5880,
       7330
      ],
      "premium": [
       7330,
       7920
      ]
     },
     "sources": [
      "checkatrade-rewire",
      "mjq-rewire"
     ]
    }
   ],
   "headline": "house-3"
  },
  {
   "id": "roof",
   "name": "New roof",
   "short": "Roof",
   "page": "/costs/new-roof/",
   "vat": 0.2,
   "regionSensitivity": 0.9,
   "question": "What roof?",
   "finishNames": {
    "budget": "Concrete tiles",
    "mid": "Clay tiles",
    "premium": "Natural slate"
   },
   "variants": [
    {
     "id": "terrace",
     "name": "Pitched roof, terraced house",
     "basis": "total",
     "rates": {
      "budget": [
       4580,
       6250
      ],
      "mid": [
       6250,
       8330
      ],
      "premium": [
       8330,
       11670
      ]
     },
     "sources": [
      "checkatrade-roof",
      "hr-roof"
     ]
    },
    {
     "id": "semi",
     "name": "Pitched roof, semi-detached house",
     "basis": "total",
     "rates": {
      "budget": [
       6670,
       8750
      ],
      "mid": [
       8750,
       11670
      ],
      "premium": [
       11670,
       15830
      ]
     },
     "sources": [
      "checkatrade-roof",
      "hr-roof"
     ]
    },
    {
     "id": "detached",
     "name": "Pitched roof, detached house",
     "basis": "total",
     "rates": {
      "budget": [
       9170,
       12500
      ],
      "mid": [
       12500,
       17500
      ],
      "premium": [
       17500,
       23330
      ]
     },
     "sources": [
      "checkatrade-roof",
      "hr-roof"
     ]
    },
    {
     "id": "flat",
     "name": "Flat roof",
     "basis": "per_m2",
     "defaultSize": 20,
     "presets": [
      10,
      20,
      40
     ],
     "min": 4,
     "max": 200,
     "minimumExVat": 1250,
     "finishNames": {
      "budget": "Felt",
      "mid": "EPDM rubber",
      "premium": "GRP fibreglass"
     },
     "rates": {
      "budget": [
       54,
       83
      ],
      "mid": [
       75,
       108
      ],
      "premium": [
       88,
       125
      ]
     },
     "sources": [
      "checkatrade-flatroof",
      "mybuilder-flatroof"
     ]
    }
   ],
   "headline": "semi"
  },
  {
   "id": "knock-through",
   "name": "Knock-through with steel beam",
   "short": "Knock-through",
   "page": "/costs/knock-through-wall/",
   "vat": 0.2,
   "regionSensitivity": 1.0,
   "question": "Width of the opening",
   "noFinish": true,
   "variants": [
    {
     "id": "narrow",
     "name": "Up to 2 m",
     "basis": "total",
     "range": [
      1500,
      2500
     ],
     "sources": [
      "checkatrade-wall",
      "checkatrade-rsj",
      "mjq-wall"
     ]
    },
    {
     "id": "medium",
     "name": "3 to 4 m",
     "basis": "total",
     "range": [
      2500,
      4500
     ],
     "sources": [
      "checkatrade-wall",
      "checkatrade-rsj",
      "mjq-wall"
     ]
    },
    {
     "id": "wide",
     "name": "Wider than 4 m or complex",
     "basis": "total",
     "range": [
      4500,
      7000
     ],
     "sources": [
      "checkatrade-wall",
      "mjq-wall"
     ]
    }
   ],
   "headline": "medium"
  },
  {
   "id": "boiler",
   "name": "New boiler",
   "short": "Boiler",
   "page": "/costs/new-boiler/",
   "vat": 0.2,
   "regionSensitivity": 0.5,
   "question": "What kind of job?",
   "variants": [
    {
     "id": "combi-swap",
     "name": "Combi boiler, like-for-like swap",
     "basis": "total",
     "rates": {
      "budget": [
       1670,
       2080
      ],
      "mid": [
       2080,
       2670
      ],
      "premium": [
       2670,
       3330
      ]
     },
     "sources": [
      "checkatrade-boiler",
      "mybuilder-boiler"
     ]
    },
    {
     "id": "combi-conversion",
     "name": "Convert a system or regular boiler to a combi",
     "basis": "total",
     "noFinish": true,
     "range": [
      2500,
      3750
     ],
     "sources": [
      "checkatrade-boiler"
     ]
    }
   ],
   "headline": "combi-swap"
  },
  {
   "id": "heat-pump",
   "name": "Air source heat pump",
   "short": "Heat pump",
   "page": "/costs/heat-pump/",
   "vat": 0.0,
   "regionSensitivity": 0.3,
   "question": "Home size",
   "noFinish": true,
   "grant": {
    "name": "Boiler Upgrade Scheme grant (England and Wales)",
    "amount": 7500
   },
   "variants": [
    {
     "id": "home-2",
     "name": "2-bed home",
     "basis": "total",
     "range": [
      10000,
      12000
     ],
     "sources": [
      "mjq-heatpump",
      "nesta-bus",
      "gov-bus"
     ]
    },
    {
     "id": "home-3",
     "name": "3-bed home",
     "basis": "total",
     "range": [
      12000,
      15000
     ],
     "sources": [
      "mjq-heatpump",
      "nesta-bus",
      "gov-bus"
     ]
    },
    {
     "id": "home-4",
     "name": "4-bed home or larger",
     "basis": "total",
     "range": [
      15000,
      18000
     ],
     "sources": [
      "mjq-heatpump",
      "nesta-bus",
      "gov-bus"
     ]
    }
   ],
   "headline": "home-3"
  },
  {
   "id": "windows",
   "name": "Replacement windows",
   "short": "Windows",
   "page": "/costs/windows/",
   "vat": 0.2,
   "regionSensitivity": 0.5,
   "question": "Home size",
   "variants": [
    {
     "id": "house-2",
     "name": "2-bed house (about 7 windows)",
     "basis": "total",
     "rates": {
      "budget": [
       2330,
       3210
      ],
      "mid": [
       3210,
       4380
      ],
      "premium": [
       4380,
       5830
      ]
     },
     "sources": [
      "checkatrade-windows",
      "mybuilder-windows"
     ],
     "assumption": "Scaled at 0.7 x the 3-bed figure by window count (Estiquote assumption)."
    },
    {
     "id": "house-3",
     "name": "3-bed semi (about 10 windows)",
     "basis": "total",
     "rates": {
      "budget": [
       3330,
       4580
      ],
      "mid": [
       4580,
       6250
      ],
      "premium": [
       6250,
       8330
      ]
     },
     "sources": [
      "checkatrade-windows",
      "mybuilder-windows"
     ]
    },
    {
     "id": "house-4",
     "name": "4-bed house (about 13 windows)",
     "basis": "total",
     "rates": {
      "budget": [
       4330,
       5950
      ],
      "mid": [
       5950,
       8120
      ],
      "premium": [
       8120,
       10830
      ]
     },
     "sources": [
      "checkatrade-windows",
      "mybuilder-windows"
     ],
     "assumption": "Scaled at 1.3 x the 3-bed figure by window count (Estiquote assumption)."
    }
   ],
   "headline": "house-3"
  }
 ],
 "fees": {
  "items": {
   "survey": {
    "name": "Measured survey",
    "range": [
     500,
     1500
    ],
    "vat": 0.2,
    "sources": [
     "harper-survey"
    ]
   },
   "design-small": {
    "name": "Design drawings (planning and building regulations)",
    "range": [
     3000,
     5000
    ],
    "vat": 0.2,
    "sources": [
     "checkatrade-architect",
     "buildit-extension"
    ]
   },
   "design-large": {
    "name": "Design drawings (planning and building regulations)",
    "range": [
     4000,
     7000
    ],
    "vat": 0.2,
    "sources": [
     "checkatrade-architect"
    ]
   },
   "design-garage": {
    "name": "Building regulations drawings",
    "range": [
     1000,
     2500
    ],
    "vat": 0.2,
    "sources": [
     "checkatrade-architect"
    ]
   },
   "engineer": {
    "name": "Structural engineer",
    "range": [
     750,
     2500
    ],
    "vat": 0.2,
    "sources": [
     "checkatrade-engineer",
     "hr-extension"
    ]
   },
   "bc-ext-small": {
    "name": "Building control (council, full plans)",
    "range": [
     613,
     840
    ],
    "vat": 0.2,
    "sources": [
     "estiquote-bc"
    ],
    "note": "Middle half of 91 councils in England and Wales for a 10 to 40 m² extension"
   },
   "bc-ext-large": {
    "name": "Building control (council, full plans)",
    "range": [
     717,
     1035
    ],
    "vat": 0.2,
    "sources": [
     "estiquote-bc"
    ],
    "note": "Middle half of 90 councils in England and Wales for extensions over 40 m²"
   },
   "bc-loft": {
    "name": "Building control (council, full plans)",
    "range": [
     622,
     861
    ],
    "vat": 0.2,
    "sources": [
     "estiquote-bc"
    ],
    "note": "Middle half of 90 councils in England and Wales for a loft conversion"
   },
   "bc-garage": {
    "name": "Building control (council, full plans)",
    "range": [
     382,
     546
    ],
    "vat": 0.2,
    "sources": [
     "estiquote-bc"
    ],
    "note": "Middle half of 77 councils in England and Wales for a garage conversion"
   },
   "planning": {
    "name": "Householder planning application (England)",
    "range": [
     548,
     548
    ],
    "vat": 0.0,
    "optional": true,
    "sources": [
     "planning-portal-fees"
    ],
    "note": "Only if your project needs planning permission"
   },
   "ldc": {
    "name": "Lawful development certificate (England)",
    "range": [
     274,
     274
    ],
    "vat": 0.0,
    "optional": true,
    "sources": [
     "planning-portal-fees"
    ],
    "note": "Optional proof that permitted development applies"
   },
   "party-wall": {
    "name": "Party wall surveyor (per neighbour)",
    "range": [
     900,
     1500
    ],
    "vat": 0.2,
    "optional": true,
    "sources": [
     "checkatrade-partywall"
    ],
    "note": "Only if you build on or near a shared wall"
   }
  },
  "sets": {
   "extension-small": [
    "survey",
    "design-small",
    "engineer",
    "bc-ext-small",
    "planning",
    "party-wall"
   ],
   "extension-large": [
    "survey",
    "design-large",
    "engineer",
    "bc-ext-large",
    "planning",
    "party-wall"
   ],
   "loft": [
    "design-small",
    "engineer",
    "bc-loft",
    "ldc",
    "party-wall"
   ],
   "garage": [
    "design-garage",
    "bc-garage"
   ]
  }
 },
 "sources": {
  "checkatrade-extension": {
   "name": "Checkatrade: House extension cost guide (June 2026)",
   "url": "https://www.checkatrade.com/blog/cost-guides/house-extension-cost/"
  },
  "fmb-single": {
   "name": "Federation of Master Builders: Single-storey extension costs (March 2026)",
   "url": "https://www.fmb.org.uk/resource/single-storey-extension-costs-a-practical-guide-for-homeowners.html"
  },
  "fmb-double": {
   "name": "Federation of Master Builders: Two-storey extension costs (January 2026)",
   "url": "https://www.fmb.org.uk/resource/two-storey-extension-costs.html"
  },
  "hr-extension": {
   "name": "Homebuilding & Renovating: How much does an extension cost (February 2026)",
   "url": "https://www.homebuilding.co.uk/advice/how-much-does-an-extension-cost"
  },
  "buildit-extension": {
   "name": "Build It: Extension cost guide 2026 (August 2026)",
   "url": "https://www.self-build.co.uk/extension-cost-guide/"
  },
  "mjq-extension": {
   "name": "MyJobQuote: House extension cost guide (August 2026)",
   "url": "https://www.myjobquote.co.uk/costs/house-extension"
  },
  "checkatrade-side-return": {
   "name": "Checkatrade: Side return extension cost (September 2026)",
   "url": "https://www.checkatrade.com/blog/cost-guides/side-return-extension-cost/"
  },
  "harper-wrap": {
   "name": "Harper Latter Architects: Wraparound extension cost guide (April 2026)",
   "url": "https://www.harperlatterarchitects.co.uk/post/wraparound-extension-cost"
  },
  "checkatrade-kitchen-ext": {
   "name": "Checkatrade: Kitchen extension cost (April 2026)",
   "url": "https://www.checkatrade.com/blog/cost-guides/kitchen-extension-cost/"
  },
  "fmb-kitchen-ext": {
   "name": "Federation of Master Builders: Kitchen extension cost 2026 (February 2026)",
   "url": "https://www.fmb.org.uk/resource/kitchen-extension-cost-2026-how-much-should-you-budget.html"
  },
  "checkatrade-loft": {
   "name": "Checkatrade: Loft conversion cost (March 2026)",
   "url": "https://www.checkatrade.com/blog/cost-guides/loft-conversion-cost/"
  },
  "hr-loft": {
   "name": "Homebuilding & Renovating: Loft conversion costs (July 2026)",
   "url": "https://www.homebuilding.co.uk/advice/loft-conversion-costs"
  },
  "fmb-loft": {
   "name": "Federation of Master Builders: Loft conversion cost breakdown (September 2025)",
   "url": "https://www.fmb.org.uk/resource/loft-conversion-cost-a-breakdown-of-costs.html"
  },
  "mjq-loft": {
   "name": "MyJobQuote: Loft conversion cost (September 2026)",
   "url": "https://www.myjobquote.co.uk/costs/loft-conversion"
  },
  "checkatrade-kitchen": {
   "name": "Checkatrade: New kitchen cost (March 2026)",
   "url": "https://www.checkatrade.com/blog/cost-guides/new-kitchen-cost/"
  },
  "mjq-kitchen": {
   "name": "MyJobQuote: Kitchen fitting cost guide (August 2026)",
   "url": "https://www.myjobquote.co.uk/costs/remodel-a-kitchen"
  },
  "mybuilder-kitchen": {
   "name": "MyBuilder: New kitchen cost guide (August 2026)",
   "url": "https://www.mybuilder.com/kitchen-fitting/price-guides/new-kitchen-cost"
  },
  "checkatrade-kitchen-fitting": {
   "name": "Checkatrade: Kitchen fitting cost (June 2026)",
   "url": "https://www.checkatrade.com/blog/cost-guides/kitchen-fitting-cost/"
  },
  "checkatrade-bathroom": {
   "name": "Checkatrade: New bathroom cost (March 2026)",
   "url": "https://www.checkatrade.com/blog/cost-guides/new-bathroom-cost/"
  },
  "mjq-bathroom": {
   "name": "MyJobQuote: New bathroom cost guide (July 2026)",
   "url": "https://www.myjobquote.co.uk/costs/full-bathroom-cost"
  },
  "checkatrade-ensuite": {
   "name": "Checkatrade: Cost to add an en-suite (June 2026)",
   "url": "https://www.checkatrade.com/blog/cost-guides/ensuite-bathroom-installation-cost/"
  },
  "checkatrade-wetroom": {
   "name": "Checkatrade: Wet room installation cost (June 2026)",
   "url": "https://www.checkatrade.com/blog/cost-guides/wet-room-installation-cost/"
  },
  "mjq-wetroom": {
   "name": "MyJobQuote: Wet room cost (September 2026)",
   "url": "https://www.myjobquote.co.uk/costs/wet-room-cost"
  },
  "checkatrade-wc": {
   "name": "Checkatrade: Installing a downstairs toilet cost (May 2026)",
   "url": "https://www.checkatrade.com/blog/cost-guides/installing-downstairs-toilet-cost/"
  },
  "mybuilder-wc": {
   "name": "MyBuilder: Downstairs toilet cost (August 2026)",
   "url": "https://www.mybuilder.com/bathroom-fitting/price-guides/downstairs-toilet-cost"
  },
  "checkatrade-garage": {
   "name": "Checkatrade: Garage conversion cost (May 2026)",
   "url": "https://www.checkatrade.com/blog/cost-guides/garage-conversion-cost/"
  },
  "fmb-garage": {
   "name": "Federation of Master Builders: Garage conversion costs (February 2026)",
   "url": "https://www.fmb.org.uk/resource/garage-conversion-costs-uk.html"
  },
  "mybuilder-garage": {
   "name": "MyBuilder: Garage conversion cost (August 2026)",
   "url": "https://www.mybuilder.com/conversions/price-guides/garage-conversion-cost"
  },
  "checkatrade-renovation": {
   "name": "Checkatrade: House renovation cost (April 2026)",
   "url": "https://www.checkatrade.com/blog/cost-guides/cost-renovating-house/"
  },
  "mybuilder-renovation": {
   "name": "MyBuilder: House renovation cost guide (August 2026)",
   "url": "https://www.mybuilder.com/restoration-refurbishment/price-guides/house-renovation-cost"
  },
  "buildit-house": {
   "name": "Build It: What does it cost to build a house (September 2026)",
   "url": "https://www.self-build.co.uk/what-does-it-cost-to-build-a-house/"
  },
  "hr-house": {
   "name": "Homebuilding & Renovating: How much does it cost to build a house (February 2026)",
   "url": "https://www.homebuilding.co.uk/advice/how-much-does-it-cost-to-build-a-house"
  },
  "checkatrade-house": {
   "name": "Checkatrade: Cost to build a house (April 2026)",
   "url": "https://www.checkatrade.com/blog/cost-guides/cost-build-house/"
  },
  "checkatrade-rewire": {
   "name": "Checkatrade: House rewiring cost (January 2026)",
   "url": "https://www.checkatrade.com/blog/cost-guides/rewire-house-cost/"
  },
  "mybuilder-rewire": {
   "name": "MyBuilder: Cost to rewire a house (August 2026)",
   "url": "https://www.mybuilder.com/electrical/price-guides/cost-to-rewire-a-house"
  },
  "mjq-rewire": {
   "name": "MyJobQuote: Rewiring a house cost (September 2026)",
   "url": "https://www.myjobquote.co.uk/costs/rewiring-a-house"
  },
  "checkatrade-roof": {
   "name": "Checkatrade: Roof replacement cost (June 2026)",
   "url": "https://www.checkatrade.com/blog/cost-guides/roof-replacement-cost/"
  },
  "hr-roof": {
   "name": "Homebuilding & Renovating: How much does a new roof cost (September 2025)",
   "url": "https://www.homebuilding.co.uk/advice/how-much-does-a-new-roof-cost"
  },
  "checkatrade-flatroof": {
   "name": "Checkatrade: Flat roof replacement costs (February 2026)",
   "url": "https://www.checkatrade.com/blog/cost-guides/flat-roof-replacement-costs/"
  },
  "mybuilder-flatroof": {
   "name": "MyBuilder: Flat roof replacement cost (August 2026)",
   "url": "https://www.mybuilder.com/roofing/price-guides/flat-roof-cost"
  },
  "checkatrade-wall": {
   "name": "Checkatrade: Load-bearing wall removal cost (March 2026)",
   "url": "https://www.checkatrade.com/blog/cost-guides/cost-remove-load-bearing-wall/"
  },
  "checkatrade-rsj": {
   "name": "Checkatrade: RSJ cost (August 2026)",
   "url": "https://www.checkatrade.com/blog/cost-guides/rsj-cost/"
  },
  "mjq-wall": {
   "name": "MyJobQuote: Load-bearing wall removal cost (July 2026)",
   "url": "https://www.myjobquote.co.uk/costs/removing-a-load-bearing-wall"
  },
  "checkatrade-boiler": {
   "name": "Checkatrade: New boiler cost (March 2026)",
   "url": "https://www.checkatrade.com/blog/cost-guides/new-boiler-cost/"
  },
  "mybuilder-boiler": {
   "name": "MyBuilder: Boiler replacement cost (August 2026)",
   "url": "https://www.mybuilder.com/central-heating/price-guides/boiler-replacement-cost"
  },
  "nesta-bus": {
   "name": "Nesta: Four years of the Boiler Upgrade Scheme (April 2026)",
   "url": "https://www.nesta.org.uk/blog/four-years-boiler-upgrade-scheme-four-charts/"
  },
  "gov-bus": {
   "name": "GOV.UK: Boiler Upgrade Scheme, what you can get",
   "url": "https://www.gov.uk/apply-boiler-upgrade-scheme/what-you-can-get"
  },
  "mjq-heatpump": {
   "name": "MyJobQuote: Air source heat pump installation cost (September 2026)",
   "url": "https://www.myjobquote.co.uk/costs/air-source-heating-pump"
  },
  "checkatrade-windows": {
   "name": "Checkatrade: New windows cost guide (June 2026)",
   "url": "https://www.checkatrade.com/blog/cost-guides/new-windows-cost-guide-and-calculator/"
  },
  "mybuilder-windows": {
   "name": "MyBuilder: Double glazing cost (August 2026)",
   "url": "https://www.mybuilder.com/windows-door-fitting/price-guides/double-glazing-cost"
  },
  "planning-portal-fees": {
   "name": "Planning Portal: Application fees in England from 1 April 2026",
   "url": "https://ecab.planningportal.co.uk/uploads/english_application_fees.pdf"
  },
  "checkatrade-architect": {
   "name": "Checkatrade: Architect fees",
   "url": "https://www.checkatrade.com/blog/cost-guides/architect-fees/"
  },
  "checkatrade-engineer": {
   "name": "Checkatrade: Structural engineer costs (June 2026)",
   "url": "https://www.checkatrade.com/blog/cost-guides/structural-engineer-costs/"
  },
  "checkatrade-partywall": {
   "name": "Checkatrade: Party wall surveyor cost (June 2026)",
   "url": "https://www.checkatrade.com/blog/cost-guides/party-wall-surveyor-cost/"
  },
  "harper-survey": {
   "name": "Harper Latter Architects: Measured building survey cost (August 2026)",
   "url": "https://www.harperlatterarchitects.co.uk/post/measured-building-survey-cost"
  },
  "estiquote-bc": {
   "name": "Estiquote: Building control fees at 92 councils (September 2026)",
   "url": "https://estiquote.co.uk/costs/building-control-fees/"
  },
  "gov-vat-708": {
   "name": "GOV.UK: Buildings and construction (VAT Notice 708)",
   "url": "https://www.gov.uk/guidance/buildings-and-construction-vat-notice-708"
  },
  "gov-vat-rates": {
   "name": "GOV.UK: Rates of VAT on different goods and services",
   "url": "https://www.gov.uk/guidance/rates-of-vat-on-different-goods-and-services"
  },
  "gov-vat-7086": {
   "name": "GOV.UK: VAT on energy-saving materials and heating equipment (Notice 708/6)",
   "url": "https://www.gov.uk/guidance/vat-on-energy-saving-materials-and-heating-equipment-notice-7086"
  },
  "bcis-forecast": {
   "name": "BCIS five-year forecast, via Specification Online (June 2026)",
   "url": "https://specificationonline.co.uk/articles/2026-06-30/bcis/updated-five-year-construction-industry-forecast-revealed-by-bcis"
  },
  "nitrades": {
   "name": "NI Trades: Northern Ireland home improvement cost index 2026",
   "url": "https://nitrades.co.uk/research/ni-home-improvement-cost-index-2026"
  }
 },
 "assumptions": [
  "Figures are planning ranges built from published 2026 UK cost guides and industry indices, not quotes.",
  "Extension, loft, garage, renovation and knock-through figures are treated as excluding VAT; kitchen, bathroom, rewire, roof, boiler and window figures are treated as prices paid, which include VAT.",
  "Regional factors are Estiquote's synthesis of published regional comparisons (FMB, Checkatrade, Build It, Homebuilding & Renovating, MyJobQuote, NI Trades); no complete public set exists.",
  "Material-heavy projects (kitchens, bathrooms, boilers, windows) apply only part of the regional factor, because fitted products cost much the same across the UK.",
  "Extensions smaller than the stated threshold carry a small-size uplift, because fixed costs do not shrink with floor area.",
  "Loft conversion totals are for about 30 m² of new floor area and scale less than proportionally with size.",
  "Contingency of 15% is a planning allowance, not a cost."
 ]
}