Industrial metal-roof waterproofing project in Verna, Goa
An operational manufacturing and storage facility in Verna Industrial Estate experienced recurring leakage through its profiled metal-sheet roof.
During the 2024 monsoon, rainwater entered above production equipment, two finished-goods storage areas and a section containing an electrical distribution panel. Temporary tarpaulins, plastic sheeting and catch buckets were no longer sufficient to manage the problem.
Inspection identified multiple failures in the roof fixings, sheet seams, gutter and ventilation flashing. These defects were corrected before a liquid-applied waterproofing treatment was applied across the prepared roof.
Project overview
Location: Verna Industrial Estate, South Goa
Property: Manufacturing and storage facility
Construction: Steel frame with profiled metal-sheet roof
Property age: Approximately 11 years
Project completed: October 2024
Roof area: Approximately 4,800 sq. ft.
Project duration: Eleven working days
Treatment: Gutter reinstatement, flashing and seam repairs, fixing-point treatment and liquid-applied roof waterproofing
Testing: Controlled water testing followed by post-rainfall inspection
Operational status: Production continued throughout the project
Warranty: Five-year workmanship warranty on the specified waterproofing and detail repairs
The problem
Active roof leakage was affecting the main production hall and adjoining finished-goods storage bay.
The facility had been managing the leakage using temporary measures during the monsoon. Tarpaulin was installed over the worst-affected roof areas, while buckets and plastic sheeting were placed inside the building.
The leakage created three operational concerns:
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Water was dripping close to production equipment.
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Finished-goods storage areas required temporary protection.
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One leakage zone was located near an electrical distribution panel.
The proximity of water to the electrical equipment was identified as a formal risk during the facility’s annual safety review.
Inspecting the industrial roof
The roof was inspected from inside the facility and externally using scaffold access.
Leakage was concentrated in four zones:
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Two separated sheet seams near the roof ridge.
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A gutter section along the eastern elevation.
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Flashing around a rooftop ventilation unit.
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Numerous exposed roof-fixing points across the production hall.
Deteriorated fixing seals
The washers and seals around more than 340 exposed roof fixings had deteriorated.
Once the seals around a fixing fail, rainwater can enter around the screw and follow the steel structure or underside of the sheet before dripping at a different position inside the building.
Open sheet seams
The original sealing material between metal-sheet overlaps had deteriorated at two ridge locations.
Wind-driven rain was entering these openings and travelling beneath the roof sheets.
Detached gutter section
A section of box gutter approximately four metres long had pulled away from its support and adjoining flashing after bracket failure.
The resulting gap directed water into the building during sustained rainfall.
Failed ventilation flashing
Flashing around a rooftop ventilation unit had cracked and lifted.
Water entering around the flashing was travelling down the ventilation duct and into the storage area.
Why the previous treatment failed
During the previous monsoons, a consumer-grade bituminous coating had been applied to visible fixing points and sheet overlaps.
The metal surface had not been cleaned and prepared adequately. Much of the coating had therefore detached from the roof.
The temporary repair also did not address the failed gutter brackets, open seams or damaged ventilation flashing.
A successful solution required these physical defects to be repaired before the wider waterproofing treatment was applied.
Industrial roof repair strategy
The project was divided into two phases.
Phase one: Repairing the defective details
The first phase addressed the individual defects that were directing water into the building:
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Reinstatement of the failed gutter section.
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Replacement of damaged ventilation flashing.
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Resealing of open sheet seams.
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Treatment of deteriorated roof-fixing points.
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Removal of loose previous repair material.
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Cleaning of roof and gutter surfaces.
Phase two: Applying the protective waterproofing system
After the defective details had been repaired, a compatible liquid-applied elastomeric waterproofing system was applied across the prepared roof.
The treatment created continuous protection over the roof surface, sheet laps, fixing points and repaired junctions.
Work completed
Roof and gutter cleaning
Organic material, silt and debris were removed from the roof and gutters.
Loose previous coating and localised surface corrosion were mechanically removed from the affected areas to provide a stable surface for the new treatment.
Gutter reinstatement
The failed box-gutter section was replaced and secured using new support brackets.
Its junction with the wall and adjoining roof details was resealed to prevent rainwater from passing behind the gutter
Ventilation flashing repair
The cracked flashing around the rooftop ventilation unit was removed.
New mechanically secured flashing was installed and sealed carefully at all edges and junctions.
Sheet-seam repair
The separated ridge seams were cleaned, prepared and resealed with a flexible weather-resistant joint sealant.
Fixing-point treatment
More than 340 exposed roof-fixing points were inspected and treated individually before the wider waterproofing system was applied.
Wider roof waterproofing
Following preparation and detail repairs, the specified liquid-applied waterproofing system was installed across the roof.
The required curing interval was observed between coats, and particular attention was given to:
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Fixing points.
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Sheet overlaps.
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Ridge lines.
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Flashing edges.
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Gutter junctions.
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Changes in roof level.
Completing the work without stopping production
The manufacturing facility operated a regular production shift from 8:00 am to 5:00 pm and could not close during the project.
Most work was therefore undertaken externally. Internal inspections were scheduled before or after the production shift wherever possible.
Heat-producing and higher-risk work was carried out during restricted periods so that it did not take place directly above occupied production areas.
The project was undertaken in October, during Goa’s retreating-monsoon period. Weather forecasts and surface conditions were monitored daily. Work was suspended when rainfall or surface moisture prevented safe preparation and application.
Testing and result
Controlled water testing was carried out on the reinstated gutter and repaired ventilation flashing.
Water was directed at each repaired junction for 30 minutes while the interior of the building was monitored. No ingress was observed.
A second inspection was conducted after the first rainfall following completion. No dripping, seepage or fresh damp marks appeared in any of the four previously affected zones.
The temporary tarpaulins, plastic sheeting and catch buckets were removed. The electrical-panel area was subsequently cleared for normal operations following the facility’s post-project safety review.
The facility continued operating without recurrence through the following dry season and 2025 pre-monsoon period.
A five-year workmanship warranty was provided for the specified roof waterproofing, seam treatment, gutter reinstatement and flashing repairs. The warranty requires routine gutter clearance and a visual roof inspection before each monsoon.
What this project demonstrates
Industrial metal-roof leakage often involves several failed details rather than one isolated hole.
In this project:
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Hundreds of fixing seals had deteriorated.
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Two roof-sheet seams had separated.
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A structural gutter support had failed.
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Ventilation flashing had cracked and lifted.
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Earlier surface coating had detached because the roof was not prepared properly.
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Production constraints required the work to be phased around an operational facility.
Repairing the gutter, flashing, seams and fixing points before applying the wider system was essential to resolving the leakage.
Project documentation
Roof inspection: Failed fixing seals, open seams and damaged flashing recorded before repair.
Detail repairs: Gutter, ventilation flashing and sheet junctions repaired before the wider treatment.
Waterproofing application: Protective waterproofing applied across the prepared metal-roof surface.
Need terrace waterproofing in Panjim?
If a factory, warehouse or commercial building has leaking sheet laps, failed gutters, deteriorated fasteners or water entering around rooftop equipment, the complete roof should be inspected before temporary coatings are applied.
Goa Waterproofing Service provides roof waterproofing and leak-repair services in Verna and across South Goa.