Lifespan
How Long a Fibreglass Roof Lasts
25 to 35 years, when it's laid on a sound deck in dry weather and the outlet is kept clear. GRP materials often carry a 20 to 25-year guarantee.
What makes a GRP roof fail early, and how to keep it going.
Free, no obligation. One local company prices it, not five.
Why some GRP roofs crack early
- Laid in damp weather, or on a damp deck: the laminate doesn't bond.
- A deck that moves: unsupported board edges crack the GRP above them.
- Trims only nailed, not bonded and laminated in.
- Water that sits: no fall, or a blocked outlet.
- A thin laminate: too little resin or a light mat where the roof is walked on.
Keeping a GRP roof going
- Clear leaves from the outlet and gutter every autumn.
- Look for hairline cracks at the trims and the wall each spring.
- Don't drag ladders or furniture across it.
- A tired topcoat can be recoated before the laminate under it wears.
What the guarantee should say
Ask for two guarantees in writing: the roofer's workmanship guarantee (10 years is common for a good one) and the material guarantee on the GRP system (often 20 to 25 years). Ask who gives each, how long it lasts, whether it covers the work or only the materials, and whether it needs the roofer to be trained on that system.
| Membrane | Life | What decides it |
|---|---|---|
| GRP fibreglass | 25 to 35 years | Cracks where the deck moves |
| EPDM rubber | 20 to 50+ years | The trims and corners |
| Torch-on felt | 10 to 25 years | Layers and the cap sheet |
GRP jobs we cover
New GRP roofsStrip the old roof and lay GRP. €75 to €140 a m².More on new grp roofs →
GRP over an existing roofOnly over a dry, sound deck. €1,800 to €5,000.More on grp over an existing roof →
Garage roofsThe commonest roof to go over to GRP. €1,800 to €5,200.More on garage roofs →
Extension roofsWith insulation over a heated room. €3,800 to €6,500 for 30 to 40 m².More on extension roofs →
Dormers and balconiesSmall roofs with lots of edges, and roofs you stand on.More on dormers and balconies →
GRP roof repairCracks, trims, outlets. €250 to €900.More on grp roof repair →Fibreglass roofing in every county
- Carlow1.4% flat main roofs
- Cavan0.8% flat main roofs
- Clare1.2% flat main roofs
- Cork2.5% flat main roofs
- Donegal1.0% flat main roofs
- Dublin3.0% flat main roofs
- Galway1.2% flat main roofs
- Kerry1.8% flat main roofs
- Kildare1.0% flat main roofs
- Kilkenny1.4% flat main roofs
- Laois1.2% flat main roofs
- Leitrim1.2% flat main roofs
- Limerick1.6% flat main roofs
- Longford0.9% flat main roofs
- Louth2.3% flat main roofs
- Mayo2.3% flat main roofs
- Meath1.3% flat main roofs
- Monaghan0.9% flat main roofs
- Offaly1.3% flat main roofs
- Roscommon1.2% flat main roofs
- Sligo1.4% flat main roofs
- Tipperary1.6% flat main roofs
- Waterford2.2% flat main roofs
- Westmeath1.5% flat main roofs
- Wexford2.7% flat main roofs
- Wicklow2.7% flat main roofs
Free quote
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Questions people ask
Does GRP last longer than felt?
Yes: 25 to 35 years against 10 to 25 for felt.
Why did my fibreglass roof crack?
Usually the deck moved, the trims weren't bonded, or it was laid in damp weather. A crack at a trim is often a repair; cracking across the roof usually means a new roof.
Does a GRP roof need maintenance?
Very little: keep the outlet clear and look for cracks at the edges once a year.
Get a free price for a GRP roof
One local flat roofing company, a look at the roof, a written price. Free, no obligation.