Roof inspection at a Dublin warehouse

A building that could not be closed for an inspection

The building, a large warehouse in Dublin, remained in full use throughout. The original roof structure and walls were structurally sound, but had begun to leak in places.

Engineers With Drones was asked to come in and look at whether the leaks could be isolated. Water was appearing inside the building in specific places, but the inside of a building tells you very little about which roof detail is letting the water in. Water travels, and by the time it shows up on a ceiling or on a floor it can be a long way from the defect that let it in. Answering the question properly means looking at the roof itself.

The building was occupied throughout, which ruled out the usual approaches to a roof survey. Scaffolding, a mobile elevating work platform or a ladder would all have meant cordoning off parts of a building that was in daily use, and working around the people in it.

Starting with the roof itself, from the air

To safely navigate a fully occupied site, we conducted strict airspace and ground risk assessments prior to flight. By operating from a safe standoff distance and deploying a compact drone with advanced optical zoom, we captured highly detailed surface imagery without bringing the aircraft near the workforce below.

Working that way, the team moved along the roof and recorded the defects that could be responsible for the leaks, capturing detailed imagery of each one as it was found.

Then from inside, to confirm the exact point of entry

Some of the corrosion and the ingress points were difficult to trace from outside the building. To close that gap, a small drone was flown inside the building itself. Where water had pooled, the drone was taken up close to the roof, at times to within about 15cm of the surface, to capture detailed imagery of the leak point itself.

That proximity turns a general finding into a specific one. Rather than reporting that a section of roof was suspect, the imagery could confirm that a particular fastener was the point of the leak.

Flying inside an occupied building was managed by working in small, isolated areas. A small area would be cordoned off, the drone flown and landed, and the cordon then moved on to the next location. The building stayed in use throughout, and no cherry pickers, mobile elevating work platforms or ladders were needed anywhere on the job.

What the inspection pinpointed

The inspection identified a number of issues that were considered to be causing the leaks. Each was captured in detail, and the imagery was then processed into a report for the client.

Aged translucent roof panels

Some of the translucent roof panels were now quite aged, and had been weathered by UV and by the weather. Water was leaking through some of those panels.

Missing capping at the roof apex

Some capping pieces were missing along the apex of the roof, leaving the top of the ridge exposed rather than covered.

Corrosion around the fixings

There was corrosion around the fasteners in the sheeting, and water was getting in around them in places.

At some fixings, the seal around the fastener had broken down completely, which left nothing to keep water out.

Water getting in at the joints and laps

Water was also finding its way in at the joints between sheets, which is what the internal flights were used to confirm.

An over-sheet lap left the fixings along the joint exposed, with the sheeting below it already staining.

What the client received

The captured imagery was processed in the office and put into a report, which was then presented to the client.

Leaks traced to specific, fixable defects

Rather than a general sense that the roof was leaking, the client was left with a defined set of defects: the aged translucent panels, the missing capping at the apex, and the corroded fixings in the sheeting, together with the joints where water was entering. Where the source could not be established from the roof, the internal flights confirmed it.

All of it was done without closing the building, without access equipment, and without asking anyone to leave.