NDTScan surveys historic fabric and buried features without disturbing them: ground penetrating radar for what lies beneath a floor, a wall or a field, ultrasonic and cover surveys of historic concrete, thermal and moisture surveys of fabric, and LiDAR records of the whole. The findings are reported for the conservation architect, the archaeologist or the engineer, with the limits of each method stated.
What NDTScan surveys
- Beneath floors and ground. Buried walls, foundations, vaults, culverts, graves and earlier floor levels indicated by ground penetrating radar without a single trowel, so a trial trench goes in the right place or is not needed at all.
- Within walls and vaults. Hidden openings, blocked flues, voids, timbers, ties and earlier construction behind render and plaster, where the signal reaches them.
- Historic concrete. Early twentieth-century reinforced concrete, lightweight and aerated systems including RAAC, assessed for reinforcement, cover, carbonation and corrosion risk through NDTScan's integrity surveys.
- Fabric condition. Moisture and thermal surveys of walls and roofs for damp paths, missing insulation and failed flashings, with handheld instruments that touch nothing.
- Records. LiDAR and photogrammetry of buildings, monuments and sites for a measurable 3D record, and drone imagery of roofs and towers where a flight is permitted.
Working on protected sites
Every instrument NDTScan uses on historic fabric is handheld or wheeled, battery powered, and reads from the surface; nothing is fixed to the fabric and no marking is made without the custodian's agreement. Surveys are planned around listed building and scheduled monument consents, visitor hours and the conservation team's own method statement, and the survey design is agreed with the archaeologist or conservation architect before anyone arrives. Where a reading would need a core or an opening, that is put to the custodian as a question, not done.
What a survey can and cannot tell you
Radar indicates that something is there, at a depth, with a shape; it does not say what it is made of or how old it is, and in wet clay or rubble fill its reach is short. Ultrasonics and cover meters read concrete and reinforcement, not masonry. Thermal shows a temperature difference, not its cause. NDTScan reports what each method indicated, with the confidence of each reading, and leaves the interpretation of what it means for the history of the building to the people qualified to make it.
What the custodian receives
Scaled plans of every surveyed area with the indicated features and anomalies drawn in and their depths tabulated, photographs, the method and settings used, and the confidence attached to each finding with what it must not be relied on for. Data is supplied in formats that can be archived with the site record and reused by future studies, with the survey grid recorded so it can be repeated. The interpreted report follows within an agreed number of working days.
Who instructs NDTScan
Conservation architects and engineers, archaeological units, heritage bodies and trusts, cathedral and church fabric committees, estate owners and the contractors working on protected buildings. NDTScan attends from Oxford anywhere in the UK, usually within one to two working days and same day where the diary allows.
Is NDT suitable for fragile or protected heritage sites?
Yes. The instruments read from the surface, nothing is fixed or drilled, and the survey is planned around the consents and the conservation team's method statement.
Can you inspect historic masonry and concrete for hidden damage?
Historic concrete is assessed for reinforcement, cover, carbonation, corrosion risk and internal condition. In masonry, radar indicates voids, openings and embedded features; it does not assess the mortar or the stone, which is the conservation specialist's work.
Do you work with archaeologists, heritage consultants or conservation architects?
Always. The survey design is agreed with them before the visit and the report is written for them.
Can your scans be archived or reused in future heritage studies?
Yes. Data, grids and plans are supplied in archivable formats with the method recorded, so a future survey can repeat the grid and compare.
Questions we are asked
Can you detect buried structures or voids without excavation?
Radar indicates buried walls, foundations, vaults, voids and earlier floors where the signal reaches them, with their depth, so excavation can be targeted or avoided. In wet clay and loose rubble the reach is short, and the report says where that applied.