Confined space survey of derelict buildings

Three buildings, no drawings, and nobody had been inside for decades

An engineering and architectural firm was tasked with generating a plan to redevelop a number of old buildings in Dublin city centre. A lot of these buildings were now derelict and had not actually been entered in many, many years. In fact, some of these buildings were completely isolated and shut off from entry for about 50 or 60 years — quite a long time.

The client needed to know two things: first, whether it was safe to go in to make an assessment of these buildings, and second, what the buildings looked like so they could start their pre-planning process. They realised they could not go straight in because the buildings were so old and from the outside they could see there were issues. So they asked Engineers With Drones to assist.

There were no drawings for buildings like these. They were built years and years ago, and everything from the road suggested significant internal deterioration. The challenge was to document the interiors comprehensively without putting anyone at risk.

A confined space drone built for the dark and the unknown

The drone deployed for this inspection was a confined space platform — a small, cage-protected drone with several critical features for working inside abandoned structures. It does not need a GPS signal, which is essential because GPS is unavailable inside enclosed buildings. It has onboard illumination because derelict buildings receive no natural light beyond what enters through broken windows. And it carries an excellent 4K camera for capturing very high-resolution imagery of every surface.

The protective cage surrounding the propellers allows the drone to make contact with walls, beams, and debris without crashing — essential in a narrow, cluttered, and completely unknown interior space. The pilot navigates entirely by visual reference from the live camera feed, flying the drone in through a window from outside and then systematically documenting every accessible area.

As Bob Foley, founder of Engineers With Drones, explains: "We got our confined space drone, which is a drone with onboard illumination, it does not need GPS signal, it has an excellent 4K camera for taking very high-resolution imagery, and it can fit through small windows. So from the outside we could fly the drone in through a window and then have a good look around inside the building and see what was going on."

What the inspection revealed across the three buildings

Once inside each building, the team systematically captured all aspects that might be important: beams that had been rotted out with water ingress over the years, floors that were starting to rot and collapse, roofs and ceilings that were starting to rot and collapse — documenting every defect that could be detrimental to anybody entering.

Building 1 — the old bakery

The first building was an old bakery. Inside, the drone captured the original industrial ovens from the 1960s — these beautiful old ovens for cooking bread back in the day, still sitting there decades after the last loaf came out. The drone flew in through an open window and had a good look around the whole building, documenting storage areas and then moving upstairs to where the people who ran the bakery had been living.

There was also an unusual flat roof covered in grass that needed to be captured, which the drone documented as part of the survey. The combination of decades-old living quarters above a working bakery gave the client a complete picture of the building's layout, condition, and heritage significance.

Building 2 — the storage and clerical building

The second building was an old storage and clerical building, attached to a much larger structure. It had three stories, and the drone went up and into each one in turn, having a good look around inside each level. Again, the team isolated and identified any defects with the building structure itself that could be detrimental to anybody entering.

This survey also served another purpose: it gave the client an idea of what was actually in the building and whether they could commence with demolition straight away, or whether there was something culturally sensitive or sensitive from a heritage perspective that they should pay a bit more attention to before starting work.

Building 3 — the old vat house

The third building was probably one of the most interesting — an old vat house. If you imagine a large community hall, but bigger, and inside there are giant barrels that look for all the world like whiskey barrels, but they are not whiskey barrels — they are giant wooden storage vats. All of them are suspended on an old riveted cast iron lattice work about a metre and a half off the ground, and the whole place is elevated above a large basement designed to contain any leaks or washing debris.

As Bob Foley recalls: "This building, when you went into it, there was a laboratory for testing the product from way, way back in the day. There was the old test samples still in their bottles, and there was even an old foreman's workstation and all the paperwork from way back in the day was still there. So it was an extremely interesting building from a heritage perspective."

The entire vat house was connected through underground tunnels that ran under the streets of Dublin to various other nearby facilities. The client was believed to be looking at turning this particular building into some sort of venue — an excellent candidate for it — but they needed to know the condition of the roof, the walls, and the vat structures first.

Inside this building, the drone flew up in and around all the old vats, inspecting the tops of them. The team documented where pigeons had been getting in over the years and how to isolate them, looked for leaks in the roofs, and identified a tree that was actually growing out of one of the roofs — its roots growing into the wall and then back out of the wall again. The drone flew around the whole interior, looked at the entire roof structure, all of the internal structures and walls, and captured everything in very high detail.

What the client received

All of the data captured across the three buildings was processed so that it was easy to understand. Everything was labelled correctly and a diagram was put in place so the client could understand where the drone started and ended in each building and what they were looking at. The client could then take either snippets of video or stills — whatever they wanted — and use those to plan how they were going to move to the next phase of the project.