Permanent Flat Roof Repairs in Dublin: Lava 20 & Torch-On Systems

Flat roofs on house extensions, dormers, and garages face the toughest test in Irish building maintenance: gravity. Unlike pitched slate roofs that shed rainwater instantly, a flat roof relies entirely on a subtle fall to guide rainfall toward drainage outlets.

When a roof pitch sags, or when traditional joint seams deteriorate under relentless Dublin rain, puddles form. This trapped standing water exposes older bitumen felt, fibreglass joints, and flashing seams to constant hydrostatic pressure, accelerating surface wear and finding even microscopic fissures.

Most flat roof leaks in Dublin stem from three common problems: blistered bitumen felt that splits after cycles of summer heat and winter frosts, cracked perimeter upstands where the flat roof joins exterior brickwork or parapets, and rotted chipboard decking that sags under the weight of trapped moisture.

At MP Roofing, we bring over 15 years of trade-tested waterproofing experience to every flat roof repair. Backed by €6.5 million in public liability insurance and Safe Pass certification, Mike and the crew inspect your roof on camera, show you the failing seams before starting, and deliver permanent repairs using modern liquid polyurethane systems and heavy-duty torch-on felt.

The Problem

The original flat roof covering on this Dublin home extension had reached the end of its serviceable life, suffering from failing seams and recurring water ingress around the perimeter upstands. Standing ponding water was beginning to compromise the roof deck, creating a persistent leak hazard around the skylight and threatening the interior ceiling plaster and insulation below.

The Solution

Mike and the team thoroughly prepped and leveled the underlying deck before applying a high-performance Lava 20 liquid polyurethane waterproofing system. Because this modern system is applied cold and cures into a single rubberized sheet, it completely eliminates failure-prone joint seams, torch-on fire hazards, and membrane laps. The crew seamlessly encapsulated the raised skylight curb, installed division trims to accommodate thermal movement, dressed the waterproof membrane high up the adjoining rendered house walls and parapet edges, and integrated clean corner drainage outlets to channel rainwater away smoothly.

The Result

A clean, ultra-durable, weather-impervious finish engineered to withstand persistent rainfall and UV exposure without cracking or peeling. Documented on camera from start to finish, this extension roof was handed over with high-definition completion footage and backed by MP Roofing’s written guarantee.

Is standing water on a flat roof always a sign of a leak?

Not necessarily, but ponding water significantly increases the risk of a leak developing. If water remains pooled on your flat roof for more than 48 hours after rain has stopped, the roof lacks the proper gravitational fall. Over time, standing water degrades mineral felt and tests joint seams. While an existing pool might not be actively leaking today, we can re-pitch the decking or apply seamless liquid coatings to prevent moisture from penetrating your timbers.

What are the main advantages of Lava 20 over traditional felt?

Lava 20 is a liquid polyurethane system that cures into an entirely seamless, flexible rubber sheet with zero joints or welds. Traditional felt roofs often fail where two sheets overlap; Lava 20 removes seams altogether. It also resists standing water without breaking down, requires no open flames or hot bitumen during application, and flexes naturally with the building as temperatures rise and fall.

Can a leaking flat roof be repaired without stripping everything away?

Yes. If the underlying timber joists and decking boards are dry and structurally sound, we can often carry out localized repairs. We can heat-weld SBS torch-on patches over split seams or apply a reinforced liquid polyurethane membrane over the existing mineral surface. However, if the timber decking has turned soft and rotten beneath the membrane, that section must be cut out and replaced to ensure long-term stability.

How quickly can you attend to an emergency flat roof leak?

We operate a dedicated same-day emergency dispatch service across Greater Dublin. If heavy rainfall is penetrating an extension ceiling or dripping near electrical downlights, our crew arrives the same day with cold-applied waterproof sealants and protective sheeting to isolate the ingress immediately before formulating a permanent repair.

What guarantee do you provide on flat roof repair work?

Every localized flat roof repair completed by MP Roofing—including torch-on patches, seam resealing, lead upstand repairs, and Lava 20 detailing—is covered by our written 5-year workmanship guarantee. Full flat roof replacements carry our comprehensive 20-year structural warranty.