The Roof Isn’t Leaking Yet — But the Damage Has Already Started
Flat roofs in Ireland are constantly exposed to harsh weather conditions, including heavy rainfall, standing water, and fluctuating temperatures. One of the most common problems found on felt roofing systems is ponding water combined with leaks around joints, seams, and weak points in the membrane.
What makes these issues particularly dangerous is that roof leaks are often not immediately visible. On large commercial or residential roofs, water can enter through a tiny crack, split seam, or failed joint and become trapped beneath the waterproofing layer. In many cases, the roof may not even show visible signs of leaking inside the building at first. However, the trapped moisture slowly begins to deteriorate the roofing membrane and weaken the substrate underneath over time.
Locating the exact source of the leak can be extremely difficult because water rarely travels straight down. Moisture can move horizontally beneath the roof covering and appear in completely different areas from where it originally entered. Even after identifying and repairing one leak, trapped water may continue travelling underneath the roof system, causing hidden damage in other sections. This often leads to recurring leaks, structural deterioration, insulation damage, and repeated repair costs.
These problems are not limited to old roofs or refurbishment projects. Even newly constructed buildings can suffer from water ingress if the roofing system is not properly protected from the beginning. Poor detailing, weak seams, and water retention areas can eventually create the same long-term issues.
For this reason, using the Lava 20 waterproofing system during new construction as well as refurbishment projects provides a major long-term advantage. Lava 20 creates a fully bonded, seamless waterproof membrane that helps eliminate weak joints and prevents water from penetrating beneath the surface. By stopping moisture ingress before it begins, property owners can avoid expensive repair works, internal damage, and premature roof failure — ultimately saving significant money over the lifespan of the roof.
Potential Repair Costs on a 100 sqm Roof
If trapped water and hidden leaks develop on a typical 100 sqm flat roof in Ireland, the repair costs can quickly become substantial depending on the severity of the damage:
• Leak detection and inspection: €500 – €2,000
• Localised repairs to felt and joints: €2,000 – €5,000
• Replacement of damaged insulation/substrate areas: €5,000 – €12,000
• Full roof strip and replacement (if water damage spreads extensively): €12,000 – €25,000+
• Supply and fit: 100 per sqm (€10,000+)
• Materials (Lava 20): 30 per sqm (€3,000+)
• Additional interior repairs (ceilings, plaster, electrics, mould treatment): €2,000 – €10,000+
In many cases, what initially appears to be a small leak can eventually result in tens of thousands of euros in repair costs if the underlying moisture problem is not fully resolved.
Investing in a high-performance waterproofing system like Lava 20 from the beginning can significantly reduce these risks and provide long-term protection, durability, and peace of mind.
