House Construction Cost Planning: Portsmouth, United Kingdom

Portsmouth house cost planning using the World Bank ICP 2021 national construction price-level index of 155.3, plus a GeoNames-based local comparable-search shortlist.

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Last updated September 15, 2026 · National screening observation from the [World Bank ICP 2021 API](https://api.worldbank.org/v2/sources/90/country/GBR/classification/PX.WL/series/1501200/time/YR2021/data?format=json) and [ICP data documentation](https://www.worldbank.org/en/programs/icp/data); locality and population from the [GeoNames GB dump](https://download.geonames.org/export/dump/GB.zip) (CC BY 4.0 snapshot 2026-08-26, GeoNames ID 2639996). The PLI is not a city cost/m² rate, current escalation series or tender estimate.

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Direct answer

For early house construction cost planning in Portsmouth, the World Bank ICP reports a 2021 United Kingdom construction price-level index of 155.3, with the world equal to 100. This is a national comparison—not a Portsmouth GBP/m² rate or tender estimate—so replace it with current local evidence before budgeting or procurement. The observation covers construction across United Kingdom in 2021; it does not measure a Portsmouth market basket or current house tenders. GeoNames 2639996 records the locality at 50.7990, -1.0913, with snapshot population 208,100. That ranks Portsmouth 39 of 50 listed places, while Southampton is the nearest listed peer at about 25 km. Use these facts only to plan the comparable search. Obtain current local rates on a consistent area basis, then reconcile scope, taxes, fees, contingency and escalation. Retain the source, base date and reviewer when local evidence replaces the screening ratio.

Content and cited inputs reviewed by Scott Barrington, Harth founder and architectural technology specialist · Published 2026-08-26 · Updated 2026-09-15.

What does the 155.3 construction index mean?

The World Bank ICP 2021 construction PLI for United Kingdom is 155.3, compared with a world benchmark of 100. It is a national spatial price comparison assembled for the 2021 reference year. It does not say that house work in Portsmouth costs 1.553 times a current world rate.

Which Portsmouth inputs are known?

The reproducible locality point is 50.7990, -1.0913 (GeoNames 2639996). Its snapshot population is 208,100, ranked 39 of 50 listed places; GeoNames classifies it as a second-order administrative seat in administrative area ENG. These facts shape the local comparable search, not the price.

What must a project estimate add?

For a Portsmouth house project, reconcile dwelling size, structural system, envelope specification, kitchens and bathrooms. Use a consistent gross-floor-area basis and record the following before reliance.

Estimate field	Screening record	Project requirement
National context	ICP 2021 PLI 155.3	Retain only as dated cross-country context
Local GBP/m² rate	Not supplied	Current comparable with named source and base date
Area and scope	Gross floor area; scope unresolved	Measurement standard, specification and procurement route
Additions	Not supplied	Taxes, fees, site work, contingency and escalation
Review	Automated source and arithmetic QA	Qualified local cost review

Portsmouth comparable-location search screen

This shortlist is computed from the checked GeoNames snapshot. Distance and population help prioritize where to request comparables; neither is used as a cost multiplier.

Listed place	Great-circle km from Portsmouth	Snapshot population	Admin area
Southampton	25	269,781	ENG
Brighton	67	283,870	ENG
Reading	74	318,014	ENG
Sutton	87	187,600	ENG
Croydon	95	173,314	ENG
Swindon	97	201,669	ENG
Archway	108	215,667	ENG
Dudley	201	199,059	ENG

Price-level normalization worksheet

For a validated reference rate R from a country with construction PLI P, the transparent screening calculation is R × (155.3 ÷ P). At P = 100 the dimensionless ratio is 1.553; no world cost rate is asserted. Keep the reference rate's currency, base date, area basis and scope attached.

Input	Recorded value	Release condition
Target national PLI	155.3 (World = 100, 2021)	Screening context only
Reference construction PLI P	User-supplied from the same ICP classification/year	Must match reference rate country
Validated reference rate R	User-supplied	Named source, currency, date, area and scope
Local Portsmouth adjustment	Not asserted	Replace with current local comparable evidence
Result status	Screening normalization	Not a budget, quote or tender estimate

Sources and method

National screening observation from the World Bank ICP 2021 API and ICP data documentation; locality and population from the GeoNames GB dump (CC BY 4.0 snapshot 2026-08-26, GeoNames ID 2639996). The PLI is not a city cost/m² rate, current escalation series or tender estimate.

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Frequently asked questions

Does the 155.3 index give a house cost per m² for Portsmouth?

No. 155.3 is the World Bank ICP 2021 national construction price-level index for United Kingdom, with the world equal to 100. It is a cross-country screening statistic, not a Portsmouth GBP/m² rate, escalation index, quote or tender estimate.

How should a Portsmouth house estimate replace this screening benchmark?

Collect current Portsmouth comparables on a consistent gross-floor-area basis, reconcile dwelling size, structural system, envelope specification, kitchens and bathrooms, and state base date, currency, taxes, fees, site work, contingency and escalation. A qualified local cost professional should review the resulting project estimate.

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