Timing
How Long a Fibreglass Roof Takes
Most house flat roofs take 1 to 3 days, depending on size and weather. The laminate cures in about 4 to 6 hours at 15°C or above before the topcoat, and nothing goes down in the rain.
What happens on each day, and what pushes it out.
Free, no obligation. One local company prices it, not five.
A typical GRP job
| When | What happens |
|---|---|
| Day 1 | Old felt stripped, deck checked, rotten boards or the whole deck replaced with OSB3, trims fixed |
| Day 1 or 2 | Resin and glass mat laid in one go on a dry day; corners and upstands laminated |
| After the cure | Light sanding, then the topcoat; anti-slip aggregate if it's to be walked on |
| Last | Outlets and flashings finished, skip gone |
Why it can take longer
- Rain or damp: GRP fails if it's laid wet. Expect a wait in a wet spell.
- Cold: the cure slows below about 15°C.
- A rotten deck or joists, found when the old roof comes off.
- Insulation: a warm roof adds a layer and a day.
Before the roofer comes
- Clear the room below if the deck may have to come up.
- Ask how the roof will be kept dry overnight between stages.
- Book for late spring to early autumn if you can choose: more dry, mild days.
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
Can a GRP roof be done in a day?
A small one, such as a porch or bay top, often can in good weather. Most garages and extensions take 1 to 3 days.
Can it be done in winter?
Yes, on dry, mild days, with hardener adjusted for the cold. Expect waits.
When can I walk on it?
Once the topcoat has cured. Ask the roofer; cold weather lengthens it.
Get a free price for a GRP roof
One local flat roofing company, a look at the roof, a written price. Free, no obligation.