The brief
BCHA needed a full picture of the roof condition of St Barnabas Church. The building has several roof zones, hidden parapet and box gutters, two towers and modern rooflights. It sits in a tight town-centre plot with neighbours on several sides, which makes scaffolding or a cherry picker costly and disruptive. Water was already coming in through one of the rooflights.
How we surveyed it
We flew the whole building, capturing high-resolution images from several heights and angles. That covered the nave, chancel and apse, both transepts, the porch, the towers and belfry openings, every parapet and coping, the gutters and outlets, and both rooflights. Nothing was touched, and no one had to work at height.
What the survey found
The roof was in poor to fair condition, with several problems that can’t be seen from the street:
- Blocked drainage: a box gutter choked with leaves, moss and plants several centimetres deep, plus a blocked valley gutter
- Gull nesting in a tower parapet gutter, likely blocking the outlet
- Slipped and missing slates on the nave, leaving open gaps at the eaves
- Failing masonry joints at the roof and parapet junctions, with plants growing out of the mortar
- Collapsed bird netting that had become a debris trap, holding water against the gutter
- Heavily soiled rooflights, with staining below the frame consistent with the reported leak
The outcome
The client received a defect schedule with 15 items, each graded Priority 1 (immediate), 2 (within 3 to 6 months) or 3 (planned maintenance). That gave them a clear order of work: clear the gutters, re-fix the slates, repair the rooflight and repoint the masonry, with lichen and long-term weathering planned for later. The gull nest was flagged with the wildlife law requirements, so clearance could be timed correctly.
The written report and defect schedule were produced by our survey partner, Skylens Surveys (PMCS Group), from the drone survey and imagery we captured.
Why it worked
On a historic building in a crowded town centre, a drone can see inside box and parapet gutters that are invisible from the ground. One drone survey avoided scaffolding entirely and gave the client photographic evidence for every defect.
Related: Roof & Building Inspections · Passmore Edwards Building, Camborne