Flat Roof Replacement Cost in Ireland (2026): GRP vs EPDM vs Felt

A flat roof over an extension, garage or porch is one of the first things to fail on an Irish house. Constant rain, standing water and temperature swings are hard on any waterproof membrane, and once it fails, water gets into the deck and the ceiling below.

If you are weighing up a replacement, the two questions are always the same: how much will it cost, and which material should I choose? This guide answers both, with realistic 2026 price ranges for Ireland.

How Much Does a Flat Roof Replacement Cost in Ireland in 2026?

Published Irish price guides for 2026 put a typical flat roof replacement at around €3,500 to €9,500. The biggest factor is simply the size of the roof, followed by the material and how easy it is to work on.

Roof Size	Typical Cost (Ireland)
Small garage or porch (15–20 m²)	€1,800 – €3,500
Typical extension (25–40 m²)	€3,000 – €6,000
Large extension (40–60 m²)	€4,500 – €8,500
Larger or commercial roof (60–100 m²)	€7,000 – €14,000

These are indicative market ranges, not a CraftShield quote. Every roof is different, and prices vary between Dublin, Meath, Laois and Kildare.

GRP vs EPDM vs Felt: Cost and Lifespan Compared

Most Irish flat roofs are now finished in one of three materials. Published 2026 guides give these approximate installed prices and lifespans:

Material	Approx. Cost per m² (installed)	Typical Lifespan
Torch-on felt	€55 – €110	15 – 25 years
GRP fibreglass	€75 – €150	25 – 35 years
EPDM rubber	€70 – €140	25 – 40 years

Ranges are wide because guides differ and prices are higher in some areas. Use them as a guide for comparing materials, not as a fixed price.

GRP Fibreglass Roofing

GRP (glass reinforced plastic) is laid as a liquid resin over glass matting and sets into a single, rigid, seamless surface. There are no joins for water to find.

• Best for: Roofs with awkward shapes, upstands and details, balconies and any roof people will walk on.
• Strengths: Seamless, tough, hard-wearing and very good at taking foot traffic.
• Watch out for: It needs a sound, well-prepared deck, because the rigid surface can crack if the structure moves. Quality depends heavily on the installer and on suitable weather during the install.

Our GRP fibreglass roofs carry a 25-year material guarantee. See our fibreglass roofing service for more.

EPDM Rubber Roofing

EPDM is a synthetic rubber membrane laid as a single large sheet, glued down and sealed at the edges and details.

• Best for: Simple, regularly shaped roofs, especially larger ones where one sheet can cover the whole area.
• Strengths: Flexible, quick to install, and it copes well with movement and temperature changes.
• Watch out for: It is less tough than GRP against sharp objects and heavy foot traffic. Details around edges and penetrations need to be done carefully.

Torch-On Felt Roofing

Felt is layered bitumen sheeting, bonded to the roof with a gas torch. It is the traditional low-cost option.

• Best for: Sheds, outbuildings and tight budgets, or a short-term fix.
• Strengths: Lowest upfront cost and widely available.
• Watch out for: It has the shortest lifespan, laps and seams can fail over time, and it needs a naked flame to install, which adds fire risk and care requirements.

Which Material Is Best Value?

Felt is cheapest to install but usually needs replacing sooner. GRP and EPDM cost more upfront but often last well over 25 years, so the cost per year of life is usually lower. A simple way to see it:

• Walkable roof, balcony or complex shape: GRP is usually the strongest choice.
• Simple roof, larger area, quicker job: EPDM is often excellent value.
• Small outbuilding or tight budget: Felt can make sense, as long as you accept a shorter lifespan.

The material is only part of the story. A well-installed roof in a cheaper material will beat a badly installed one in a premium material.

What Affects Your Flat Roof Quote?

• Roof size and shape: More area, upstands, corners and rooflights mean more labour.
• Condition of the deck: Rotten or damp boards or insulation must be replaced before a new membrane goes on. This is the most common reason a quote goes up.
• Insulation: Adding or upgrading insulation costs more, but it improves comfort and cuts heat loss.
• Drainage: Roofs that hold standing water may need new falls, outlets or guttering.
• Access: Scaffolding, restricted access or carrying materials through the house adds time.
• Edge details: Trims, parapet walls, flashings and rooflights all need careful detailing.
• Weather and timing: Wet or very cold weather can delay certain installs, especially GRP.
• VAT: Check whether a quote includes VAT, so you can compare like with like.

Repair or Replace?

Not every leaking flat roof needs a full replacement. Localised leaks, failed seams or damaged flashings can often be repaired for far less. Replacement is more likely when:

• The roof is near or past its expected lifespan.
• There is widespread cracking, blistering or splitting.
• Water ponds on the surface for days after rain.
• The deck or insulation underneath is wet or rotten.
• Repeated repairs are costing more than the roof is worth.

An honest inspection will tell you which route makes sense. We would rather quote a repair than sell you a roof you do not need.

How Long Does It Take?

Most residential flat roof replacements take around one to three days, depending on size, weather and whether the deck needs work. We strip the old roof, repair the deck as required, lay the new system, finish the edges and clear everything away.

Questions to Ask Before You Accept a Quote

1. What material and what thickness or specification is being used?
2. Does the price include removing the old roof and disposing of it?
3. What happens if the deck is rotten once the old roof is off, and how is that priced?
4. Is insulation included, and to what standard?
5. Are edge trims, flashings and drainage included?
6. Is VAT included?
7. What guarantee do you get, in writing, and for how long?

With CraftShield you get a full workmanship guarantee certificate once the job is complete and inspected.

Frequently Asked Questions

How much does a flat roof replacement cost in Ireland in 2026?

Published Irish price guides for 2026 put a typical flat roof replacement at roughly €3,500 to €9,500. A small garage roof of 15 to 20 square metres is often €1,800 to €3,500, while a 25 to 40 square metre extension is commonly €3,000 to €6,000. The final price depends on roof size, material, access and the condition of the deck.

Which is better for a flat roof, GRP or EPDM?

Both are good long-term choices and typically last 25 years or more. GRP fibreglass forms a seamless, rigid, hard-wearing surface that suits walkable roofs and complex shapes. EPDM rubber is a flexible single sheet that suits simple, larger roofs and is often quicker to install. The right choice depends on the roof shape, use and budget.

How long does a flat roof last?

Typical lifespans quoted for Ireland are around 15 to 25 years for felt, 25 to 35 years for GRP fibreglass and 25 to 40 years for EPDM rubber, provided the roof is installed properly and maintained.

How long does it take to replace a flat roof?

Most residential flat roof replacements take between one and three days, depending on size, weather, the material used and whether the deck needs repair.

Can a flat roof be repaired instead of replaced?

Often yes. Localised leaks, failed seams or damaged flashings can usually be repaired. Replacement is more likely when the roof has widespread cracking, ponding water, a rotten deck or is near the end of its life.

Get a Clear Flat Roof Quote

If your flat roof is leaking, ponding or getting old, a proper inspection is the cheapest first step. We will tell you whether it needs a repair or a replacement, which material fits best, and exactly what the price includes.

Contact CraftShield Roofing today for a free, no-obligation quotation.