Flat roofs · Castleknock, Dublin 15
Flat Roof Leak Repair in Castleknock, Dublin 15
Flat roof leak repair in Castleknock, Dublin 15. We prepared the existing fibreglass roof and applied a continuous Mariseal 250 liquid waterproofing membrane, with careful detailing around the rooflight, perimeter edges and wall junctions to renew the roof’s weather protection.
What needed attention
The client had begun experiencing water ingress through a flat-roof extension that was just over five years old. The existing roof was a fibreglass system with a large glazed rooflight, perimeter upstands and several junctions where the waterproofing needed careful attention. Rather than assume a single visible defect was the only source, the roof required a broader waterproofing treatment across the affected flat-roof area.
How we approached it
We prepared the existing fibreglass roof surface and treated the vulnerable roof details before applying Mariseal 250, a premium liquid-applied polyurethane waterproofing membrane. The membrane was applied continuously across the flat roof and carefully carried around the rooflight, perimeter edges, upstands and wall junctions. This approach creates a seamless waterproof layer over the existing fibreglass surface and reduces reliance on isolated patch repairs at individual joints or suspected leak points.
The finished work
The completed roof has a continuous grey Mariseal 250 waterproofing finish across the main roof area and detailed junctions. The rooflight perimeter, wall junctions and roof edges were incorporated into the waterproofing treatment, providing a renewed seamless weatherproof layer over the existing fibreglass roof. The finished work is designed to protect the extension from further water ingress while retaining the existing roof structure.
The job, in photographs
From first look to finishing details
Your roof, our next conversation
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Tell us what needs attention. We’ll explain the next step and arrange a roof assessment.