One of the most authoritative measures of the UK house building and commercial construction sectors warns of a struggle to cushion blows from international conflicts and a persistently weak domestic economy.

Glenigan’s April Construction Index shows work starting on-site declined by 17% in Q1 this year compared to Q4, remaining 18% below 2025 levels.

The Index focuses on the three months to the end of March 2026, covering all underlying projects, with a total value of £100m or less (unless otherwise indicated), with all figures seasonally adjusted. 

It’s a report which provides a detailed and comprehensive analysis of year-on-year construction data, giving built environment professionals a unique insight into sector performance over the last 12 months.

Residential construction starts dropped by 13% during the Index period and fell by 30% against 2025 figures. 

Non-residential project-starts dipped by 5% against 2025 levels, falling by 15% against the preceding three months.

Civils work starting on-site plummeted by 37% against Q4 and nosediving 34% against the previous year. 

Glenigan describes the serious challenges facing the UK construction sector as “relentless.”

And it adds that the industry remains in the tight grip of decline which, if not terminal, is having a deeply damaging effect, pushing its resilience to a breaking point.

It says: “The US-Israel/Iran War started at the end of February and shows no sign of coming to an end any time soon, resulting in considerable uncertainty that’s set to keep sector performance subdued.

“Whilst some of the negative effects are being felt in the here and now, the expected aftershock of the continued closure of the Strait of Hormuz, alongside the increasing threats posed to the Suez Canal and Red Sea, mean disruption is predicted to continue through Q2 and Q3 2026.

“Amid this maelstrom, new projects commencing in the coming months are expected to be impacted.

“This comes after work starting on site fell once again, particularly when seasonally adjusted, dropping by 17% compared to Q4 to finish almost a fifth (-18%) below 2025 levels.”

Glenigan is especially gloomy about residential construction.

The report continues about this sector: “International conflict, persisting confusion around planning policy and a weak economy continue to hinder development.

“Ice-cold investors and apprehensive potential buyers are keeping their hands firmly in their pockets for the time being.”

For Non-Residential, the index suggests that Offices remained a strong outlier, posting impressive project-start increases compared to both the previous quarter and last year.

However, these impressive figures were not nearly enough to outweigh overall disappointment in these verticals, with civils tanking against both periods covered by the Index.

Commenting on the April Index, Glenigan’s Allan Wilen says: “Superficially, looks can be deceiving. A seasonal rise during the first quarter is masking a renewed weakening in project starts.

“All three main verticals: housing, non-residential buildings and civil engineering are considerably lower than a year ago and on the previous quarter on a seasonally adjusted basis.”

He continues: “The sector is fighting on all fronts, home and abroad. Particularly, the Iran War will depress activity further near-term as private developers and house purchasers delay investment decisions due to fears of higher than anticipated interest rates, rising material costs, spiralling energy costs and stalled economic growth.

“It will have a knock-on effect on the non-residential verticals which, although many have ring-fenced funding, will no doubt be putting activity on hold to ensure they don’t waste budgets whilst rates spike.”

In particular, the index looks at the residential sector.

It states: “Residential experienced a particularly poor period, according to Glenigan’s figures. Project-starts declined by13% on the preceding three months and by almost a third (-30%) on 2025.

“Drilling a little deeper, private housing construction-starts declined by 9% against the preceding three months and by 34% against the previous year.

“Social Housing starts were similarly depressed, dropping by roughly a quarter (-24%) against the preceding three months and by 16% against the previous year.”