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Build cost index: what extension materials and building work cost now

Official price indices for construction materials (UK) and building work (Great Britain), updated as each source publishes, with the materials an extension uses and a way to restate an old builder's quote in today's prices.

Construction materials, new housing

167.4

Index, 2015 = 100, July 2026 (provisional)

Month on month
+0.4%
Year on year
+4.9%
Since Jan 2015
+66.6%

DBT Table 1a, UK. Excludes electrical and mechanical materials.

Building work prices, housing repair and maintenance

125.2

Index, 2015 = 100, June 2026

Month on month
+0.2%
Year on year
+1.6%
Since Jan 2015
+25.6%

ONS construction output prices, Great Britain. Published quarterly, so its latest month (June 2026) trails the materials index. Recent months may be revised.

Materials and building work prices since 2015

Index, 2015 = 100. Materials (DBT, UK) to July 2026; output prices (ONS, Great Britain) to June 2026. DBT materials: May to July 2026 provisional.

  • Construction materials, new housing (DBT)
  • Construction materials, repair and maintenance (DBT)
  • Output prices, new housing (ONS)
  • Output prices, housing repair and maintenance (ONS)
Source: DBT Building materials and components statistics; ONS construction output price indices. OGL v3.0. Chart: buildwiz.uk
Show data
MonthConstruction materials, new housing (DBT)Construction materials, repair and maintenance (DBT)Output prices, new housing (ONS)Output prices, housing repair and maintenance (ONS)
Jan 2015100.5101.399.099.7
Feb 2015100.6100.999.699.8
Mar 2015100.6100.8101.099.8
Apr 2015100.6100.6100.099.9
May 2015100.9100.899.999.9
June 2015100.5100.5100.399.9
July 2015100.2100.2100.4100.0
Aug 201599.899.799.7100.0
Sept 201599.499.199.6100.1
Oct 201599.198.9100.1100.2
Nov 201599.298.9100.7100.3
Dec 201598.898.399.8100.4
Jan 201698.598.0101.4100.5
Feb 201699.198.1101.6100.6
Mar 201698.998.1102.2100.7
Apr 201699.498.6102.6100.8
May 201699.899.2102.3100.9
June 2016100.399.8102.4101.0
July 2016100.299.9103.2101.1
Aug 2016100.8100.6103.3101.3
Sept 2016101.4101.2103.5101.5
Oct 2016101.3101.1104.1101.8
Nov 2016102.1101.9104.8101.9
Dec 2016102.0101.9104.9102.0
Jan 2017102.8103.0105.7102.3
Feb 2017103.9104.2105.8102.5
Mar 2017104.3104.5106.1102.7
Apr 2017104.8104.9106.1102.9
May 2017105.2105.4106.2103.0
June 2017105.3105.4106.6103.1
July 2017105.4105.5107.3103.2
Aug 2017105.6105.8107.6103.3
Sept 2017106.4106.5108.6103.3
Oct 2017106.9107.0108.3103.4
Nov 2017107.1107.5108.8103.5
Dec 2017108.1108.2108.9103.5
Jan 2018107.7108.0110.0103.8
Feb 2018109.3109.4109.6103.9
Mar 2018109.3109.6110.5104.2
Apr 2018109.7110.2110.7104.5
May 2018110.1110.6111.1104.7
June 2018110.5111.5111.4104.8
July 2018111.0112.0111.2104.8
Aug 2018111.1112.3111.0104.9
Sept 2018111.6112.9111.0105.0
Oct 2018111.3112.9111.1105.0
Nov 2018111.7113.3112.3105.1
Dec 2018111.8113.3112.3105.2
Jan 2019111.7113.0112.6105.4
Feb 2019112.4113.5113.2105.5
Mar 2019113.4114.2113.4105.7
Apr 2019113.1114.3114.1105.8
May 2019112.8114.0114.8106.1
June 2019113.3114.2115.1106.2
July 2019113.3114.0115.4106.3
Aug 2019112.8113.7115.1106.4
Sept 2019112.5113.4115.1106.3
Oct 2019112.8113.4114.6106.4
Nov 2019112.0112.6114.6106.4
Dec 2019111.5111.8114.0106.4
Jan 2020110.9111.3114.6106.5
Feb 2020111.4111.7114.6106.7
Mar 2020111.7111.7114.5106.8
Apr 2020111.7111.7114.6106.6
May 2020112.5112.2114.7106.9
June 2020111.9111.8114.8106.9
July 2020112.2112.0115.2106.9
Aug 2020112.3112.3115.3107.2
Sept 2020112.9112.9115.6107.2
Oct 2020113.5113.4115.7107.2
Nov 2020114.5114.6115.8107.2
Dec 2020116.3116.0116.0107.3
Jan 2021116.8117.1116.6107.6
Feb 2021118.9119.3116.9107.8
Mar 2021120.1120.8117.8108.0
Apr 2021121.0122.3118.5108.2
May 2021123.0124.6119.7108.7
June 2021124.7126.5120.6109.3
July 2021127.1129.3122.2110.1
Aug 2021134.2137.4123.8110.9
Sept 2021137.3141.0123.8111.4
Oct 2021138.5142.5125.5112.1
Nov 2021140.0144.1126.9112.5
Dec 2021139.8143.6126.5112.9
Jan 2022139.6143.5129.5113.5
Feb 2022140.1143.4129.7114.0
Mar 2022140.6143.6130.5114.4
Apr 2022143.6147.6133.0115.5
May 2022149.1153.9134.4116.2
June 2022153.6157.4135.5116.7
July 2022155.0159.2136.4117.2
Aug 2022153.3157.5135.8117.5
Sept 2022151.0154.7137.1118.1
Oct 2022150.5154.0138.9118.4
Nov 2022151.6154.2139.7118.5
Dec 2022151.4153.1139.4118.8
Jan 2023150.6151.6142.3119.1
Feb 2023152.4153.1143.0119.1
Mar 2023153.0153.2144.2119.4
Apr 2023153.6154.2144.8119.6
May 2023154.7155.0145.3119.8
June 2023153.9153.5145.6120.2
July 2023153.8153.2145.9120.6
Aug 2023153.9153.3145.9120.6
Sept 2023153.0152.7146.1120.7
Oct 2023152.0152.3145.3120.7
Nov 2023151.2151.4145.3120.8
Dec 2023151.1150.9144.8120.9
Jan 2024151.1150.6145.7121.1
Feb 2024151.1150.9147.2121.1
Mar 2024152.8152.1147.5121.3
Apr 2024153.4153.1148.8121.3
May 2024155.0154.7150.3121.4
June 2024155.2154.9150.1121.6
July 2024154.3154.0150.0121.6
Aug 2024154.0153.8149.6121.7
Sept 2024153.7153.3150.3121.8
Oct 2024153.3152.6151.5121.8
Nov 2024153.5152.7150.6121.9
Dec 2024153.3152.7150.2121.9
Jan 2025153.9153.3151.3122.3
Feb 2025155.0154.7152.6122.5
Mar 2025156.7155.7153.1122.6
Apr 2025157.0156.0153.2122.8
May 2025158.0157.1153.7123.0
June 2025158.8157.8154.0123.2
July 2025159.6158.7154.2123.3
Aug 2025159.3158.7154.5123.5
Sept 2025159.8158.8155.2123.5
Oct 2025160.0159.3155.3123.6
Nov 2025159.5158.4155.5123.6
Dec 2025159.6158.8154.9123.6
Jan 2026159.8158.6155.0123.7
Feb 2026160.3159.0155.5124.0
Mar 2026161.5160.2155.6124.1
Apr 2026162.9162.6156.3124.5
May 2026164.1 (p)164.3 (p)158.2124.9
June 2026166.7 (p)166.8 (p)158.4125.2
July 2026167.4 (p)167.4 (p)––

What the materials in an extension cost now

Each row is the nearest official price series for one part of an extension, as index points (2015 = 100) with the change on the month and the year before. The last column runs from October 2021, when the documented kitchen extension behind our build story started on site. The rows are unweighted and are not added together.

Build itemPrice series usedLatestMonth on monthYear on yearSince Oct 2021
Foundations concreteReady-mixed concrete (EW6M)156.7Aug 2026−1.5%−0.7%+38.5%
BlockworkConcrete products for construction (EW6K)All precast concrete products for construction, not blocks alone.196.1Aug 2026−0.1%+1.5%+45.4%
Facing bricksBricks, tiles and construction products in baked clay (EW6C)Includes clay roof tiles and other baked clay products, not bricks alone.190.4Aug 2026−0.3%+3.3%+60.7%
Cement and mortarCement (EW6I)140.7Aug 20260.0%−0.8%+25.0%
Steel beamsMetal structures and parts of structures (EW7B)All fabricated metal structures, not structural steel beams alone.164.0Aug 2026+0.7%+4.1%+19.1%
Roof and floor timberBuilders' carpentry and joinery (EVUJ)Builders' carpentry and joinery, including wooden doors and windows, not sawn structural timber.169.0Aug 2026+0.7%+4.1%+22.4%
InsulationInsulating materials (DBT Table 2, HMRX)DBT publishes only the latest 13 months of this series; ONS has no long-run series for it.207.2July 2026provisional+2.5%+4.8%+4.8%since July 2025
Plasterboard and plasterPlaster products for construction (EW6L)All plaster products for construction, not plasterboard alone.222.6Aug 2026+0.9%+7.1%+80.4%
Bifolds and windowsDoors and windows of metal (EW7C)Metal doors and windows only; uPVC and timber frames are not in this series.188.5Aug 2026−0.1%+4.1%+44.3%
ElectricsElectric wires and cables (EWKE)All electric wires and cables. The DBT materials composite excludes electrical materials.168.6Aug 2026−0.1%+12.0%+41.1%
ElectricsWiring devices (EWKF)Switches, sockets and other wiring devices. The DBT materials composite excludes electrical materials.131.9Aug 2026−0.5%−0.5%+5.7%
Floor and wall tilesCeramic tiles and flags (EW6B)173.5Aug 2026−0.3%+2.4%+67.6%
Kitchen unitsKitchen furniture (EWLX)166.9Aug 20260.0%+0.8%+39.8%
PlumbingBuilders' ware of plastic (EW4L)Plastic builders' ware, such as baths, washbasins, cisterns, tanks, and doors and windows. Plastic pipes and fittings, copper and boilers are not in it.163.1Aug 2026+0.5%+5.0%+30.3%
PlumbingPlastic plates, sheets, tubes and profiles (EW4J)Plastic pipes and fittings, but it also includes plastic sheet and profiles. Copper and boilers are not in it.173.3Aug 2026−0.2%+13.0%+28.2%
  • Where a series is broader than the item, the note under it says what else it covers. Electrics has two rows, cables and wiring devices, and plumbing has two plastic product series; neither is a single plumbing or electrics price.
  • Insulation comes from DBT Table 2, which publishes only the latest 13 months, so its last column starts from the earliest month available.
  • ONS producer price series are usually more recent than the DBT tables, and ONS revises the latest months, so the most recent figures may be revised. "not published" means the source has no figure for that month.

Update an old quote to today's prices

Enter a builder's quote and the month it was given. We scale it by the change in ONS output prices for housing work, which reflect what builders charge for finished work, labour and materials together, up to the latest published month (June 2026). Use it to sense-check an old quote, not to price a job.

Month of the quote
Kind of work

Repair and maintenance covers work on existing homes, including improvements and extensions; new housing covers new-build homes.

How to read this

  • These are producer and output price indices, not shop prices. Materials series track what manufacturers charge; output prices track what builders charge for finished work. Merchant prices, trade discounts and delivery vary around them.
  • The DBT materials composite excludes electrical and mechanical materials, so cable, wiring devices and plumbing appear only in the basket.
  • Output prices cover Great Britain and ONS publishes them quarterly, so they lag the materials index. Each figure on this page shows its own latest month: July 2026 for DBT materials and June 2026 for output prices.
  • The basket is unweighted. Each row is a named official series, several of them broader product classes standing in for the item (proxies), and we do not combine them into a single extension figure.
  • DBT marks its latest months provisional, ONS revises recent producer price months, and ONS can revise output prices for up to a year back, so the latest figures may be revised. We check for new releases every week.
  • Why materials rose faster than output prices: since Jan 2015, materials for repair and maintenance work rose 65.3% (to July 2026) while housing repair and maintenance work rose 25.6% (to June 2026). Output prices cover the whole price of the work, including labour, plant, overheads and profit, and materials are only part of it, so a jump in materials moves the price of finished work by less.

Questions

How much have building costs gone up?

UK construction materials prices for new housing rose 66.6% since Jan 2015, to July 2026 (DBT). What builders charge for housing repair and maintenance work in Great Britain rose 25.6% since Jan 2015, to June 2026 (ONS output prices). In the year to July 2026 materials rose 4.9%; in the year to June 2026 repair and maintenance work rose 1.6%.

Are building material prices still rising?

In the year to July 2026, the DBT materials index for new housing rose 4.9%. On the month before, it rose 0.4%. The latest months are provisional and may be revised. Individual materials move differently, so check the basket table for concrete, bricks, timber, insulation and the rest.

How do I adjust an old builder's quote for inflation?

Multiply the quote by the latest index value and divide by the index value for the month of the quote. The adjuster on this page does this with ONS output prices for housing work, which cover labour and materials. For example, £10,000 quoted in Oct 2021 is about £11,169 in June 2026 prices (a factor of 1.1169). Treat the answer as a guide: local demand, the builder's workload and any change to the specification move a real quote more than a national index.

What is the construction materials price index?

The Department for Business and Trade publishes monthly construction material price indices for the UK, as weighted averages of ONS producer price indices, with 2015 = 100. They track what manufacturers charge, not shop prices at a builders' merchant, and the Table 1a composites leave out electrical and mechanical materials such as cable and boilers.

Planning to project manage an extension?

Our build guides set out every stage in order, with the costs and checks at each one.

Browse the build guides

Sources and reuse

Source: Department for Business and Trade, Building materials and components statistics (Table 1a, compiled from ONS producer price indices and BCIS).

Source: Office for National Statistics, producer price indices and construction output price indices.

Contains public sector information licensed under the Open Government Licence v3.0.

Download every series (CSV) · Free to reuse under the Open Government Licence: credit the sources above, and please link to this page.

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