Specialist surveys and structural investigation for prisons, defence sites and the secure public estate.

Some of the UK’s most important structures sit behind gates, fences and vetting. Infrastruct North delivers surveying, structural investigation and materials testing inside custodial and defence environments — where every tool is accounted for, every photograph is approved and every method is agreed before anyone sets foot on site.

Working securely is a discipline, not an add-on

Our teams plan secure-estate work around the establishment’s rules, not our convenience: security inductions and clearances, tool and equipment control, escorted working, approved photography arrangements and site-specific RAMS agreed with the client, the establishment and — where required — specialist advisers such as Radiation Protection Advisers for XRF work. Programmes build in hold points so that nothing intrusive happens without written approval.

Investigation that respects the asset

Secure estates are often historic estates. Much of our work in these environments involves understanding original fabric — Victorian ironwork, early steel frames, ageing masonry — before repair or strengthening. Our staged, minimum-intervention approach combines condition surveys, non-destructive screening (XRF/PMI, hardness, ultrasonic thickness), fixing investigations and targeted testing, so the design team gets the evidence it needs with the least possible impact on the fabric.

Recent work

At HMP Usk, we delivered a heritage-led investigation of the prison’s historic handrails, brackets and landings for Clegg Associates and Galliford Try — condition survey, metallurgical screening and a pull-out testing strategy to support strengthening design. At RAF Halton, we carried out targeted structural steel testing across two 1920s aircraft hangars, providing material and condition data for structural reassessment.

And at the Royal Military Academy Sandhurst, we combined topographic survey, PAS 128 utility mapping and ultrasonic thickness testing across the estate — including a 62-point corrosion survey of the steel sheet piles supporting one of the estate’s bridges, giving the asset team a reliable condition baseline for future monitoring.

Who we help

Justice-sector frameworks and their designers and contractors. Defence infrastructure organisations and their supply chain. Local authorities and public-estate asset owners. Heritage bodies and conservation-led design teams.

Planning work on a secure or historic estate? Contact an expert — we’ll come back within one working day.