St. Andrew's Church
PROJECT OVERVIEW
AltiGeo carried out a drone-based heritage survey of St Andrew’s Church, located on St Andrew’s Street near Grafton Street, Dublin. The former Church of Ireland parish church is a notable heritage structure within the city centre and has previously housed the main Dublin tourist office.
The purpose of the survey was to create a high-resolution photogrammetric record of the roof and upper architectural elements. This allowed the conservation architects and design team to safely inspect the roof, identify areas of damage, algae growth and deterioration, and assess zones where repair or further conservation works may be required.
Survey Objective
The aim was to provide a detailed digital record of the roof condition without the need for extensive physical access or scaffolding at the initial inspection stage.
Drone photogrammetry allowed the roof to be captured from multiple angles and reviewed remotely by the design team.
This allowed the architects to:
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Inspect roof slopes, valleys, ridges, gutters, parapets, stonework and junctions.
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Identify visible defects and areas of concern.
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Mark up areas requiring repair or further investigation.
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Refer back to 4K source imagery for selected roof areas.
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Share the output with stakeholders without heavy software or large downloads.
Methodology
The drone survey was undertaken between 5:00 am and 6:15 am to minimise disruption in the busy city-centre location and to allow safer flying conditions around Grafton Street.
A total of 2,070 drone images were captured of the roof and upper elevations, with metadata recorded for processing. Overlapping photographs were taken from multiple angles to ensure accurate capture of roof planes, vertical surfaces, edges, valleys, chimneys, gutters and architectural details.
Photogrammetric Roof Model
AltiGeo processed the imagery into a detailed photogrammetric 3D model of St Andrew’s Church and its roof. The model provided a highly visual and measurable record of the existing roof condition.
The online model allows users to navigate around the building, zoom into specific areas and click on roof elements to view the associated 4K drone imagery. This provides the conservation team with a reliable way to inspect specific areas and cross-check the model against the original survey photographs.
Damage Identification and Repair Areas
The photogrammetric model was used as a visual inspection platform to identify and record areas of damage or concern. Defects such as algae growth, staining, damaged roof finishes, weathered surfaces and potential repair zones were marked directly within the model.
Each observation was linked to a specific roof location and ITM Coordinates , helping the design team understand the extent and distribution of the damage and plan repair works more effectively.
Benefits for Heritage Conservation
The drone survey provided a safe, efficient and non-intrusive method of recording the roof of a sensitive heritage structure. It allowed the conservation architects to review the roof in detail without relying only on ground-level photography or physical access.
The key benefit was the creation of a permanent digital record of the roof condition at the time of inspection, supporting conservation assessment, design coordination, repair planning and future comparison surveys.
Deliverables
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High-resolution drone imagery of the roof
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Detailed photogrammetric 3D model
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Online viewable model for easy sharing with the design team
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Clickable 4K image references within the model
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Digital record to support conservation assessment and repair planning