Comparing EPDM and Felt Roofing: Which Delivers Better Value?

Replacing a flat roof forces you into a decision between competing materials. EPDM rubber roofing keeps appearing in your research, while traditional felt still covers countless roofs across Ireland. So which option actually gives better value?

Both systems work, otherwise neither would still be widely used. But they differ significantly in how they’re installed, how they age, what they cost over time, and which problems typically show up years down the line. Budget might push you towards felt’s lower upfront price, while EPDM’s reputation for durability makes it tempting if you’re thinking longer term.

Torch application is another factor. Felt often requires open flame installation, which introduces safety risks, especially on older buildings or where there’s timber decking. EPDM, by contrast, is installed cold using adhesives and seam tape, with no flame involved.

This guide breaks down the key differences so you can choose the roofing system that matches your priorities, whether that’s cost, lifespan, ease of installation, safety, or long-term reliability.

Expected Lifespan Differences

EPDM Lifespan

A correctly installed EPDM roof typically delivers 30–50 years of service life. That isn’t marketing hype, EPDM has over six decades of proven performance in the field. Many manufacturers offer 20–25 year material warranties, and in practice EPDM regularly exceeds those warranty periods when installed well.

Felt Lifespan

Traditional felt roofing typically delivers 10–20 years, depending on build-up quality, exposure, detailing, and maintenance. Some high-quality multi-layer torch-on systems may achieve 20+ years in favourable conditions, but felt generally has a shorter predictable lifespan than EPDM.

Why the Gap Exists

EPDM and felt age very differently:

• EPDM is a synthetic rubber that is naturally resistant to UV, ozone and thermal movement. It stays flexible and stable for decades.

• Felt is bitumen-based. Over time, bitumen oxidises and becomes more brittle, which increases the risk of cracking and splitting, particularly around edges, outlets and penetrations.

If you’re planning to own the property long-term, this difference changes the overall value calculation. A felt roof may need replacing two or three times during the same period that one EPDM roof continues performing.

Installation Method Comparison

How EPDM Is Installed

EPDM is installed as a cold-applied system. The substrate is prepared, adhesive is applied, the membrane is positioned, and seams (where required) are sealed using compatible seam tape and primers.

One major advantage is sheet size. EPDM is available in large sheets that can reduce the number of seams on many roof layouts, which improves long-term reliability.

Main installation methods include:

• Fully adhered (bonded across the whole surface)

• Mechanically fixed (secured with plates and fixings)

• Ballasted (held down using stone or paving, where structure allows)

On many domestic roofs, EPDM can be watertight in a day once detailing is completed correctly.

How Felt Is Installed

Felt is typically installed as a multi-layer system, most often using torch-on application.

The installer unrolls the felt and uses a propane torch to heat the underside until the bitumen melts and bonds. Overlaps must be carefully welded, and each layer must be installed correctly before moving to the next.

A common build-up includes:

• A base layer / underlay

• An intermediate layer (depending on system)

• A mineral-finished cap sheet

Felt installation requires more time and is more sensitive to workmanship, weather conditions, and safe handling procedures.

Long-Term Reality Check (Updated 35-Year Example)

To make this comparison fair and easy to follow, the example below uses the midpoint of each installed range and assumes costs stay broadly similar in “today’s money” over time (inflation excluded for simplicity).

Installed cost assumptions (40m² roof):

• Felt midpoint installed rate: (€60 + €102) / 2 = €81/m² → €3,240

• EPDM midpoint installed rate: (€72 + €114) / 2 = €93/m² → €3,720

Replacement assumptions:

• Felt lifespan assumed at 15 years (typical real-world replacement cycle)

• EPDM lifespan assumed at 35+ years (within the normal 30–50 year range)

35-Year Total Cost Comparison (40m² roof)

Roofing Material	Initial Cost	Replacement 1	Replacement 2	Total Over 35 Years	Approx. Annual Cost
Felt Roofing	€3,240	€3,240 (Year 15)	€3,240 (Year 30)	€9,720	€278/yr
EPDM Rubber	€3,720	n/a	n/a	€3,720	€106/yr

Long-Term Value

This is where EPDM generally wins.

If a felt roof needs replacement after 12–15 years (which is common in practice on exposed roofs), the savings disappear quickly. Over 30–40 years, you may end up paying for multiple replacements, plus disruption, access costs, and internal repair risk if failures happen.

EPDM’s longer lifespan means:

• fewer replacement cycles

• lower disruption

• lower long-term cost risk

Even if the initial cost is higher, EPDM often delivers better lifetime value on buildings you intend to keep.

Safety Considerations During Installation

Torch-on felt installation involves open flame, which introduces obvious fire risk, particularly on older buildings with timber decks, dry insulation, or stored materials nearby.

Many contractors mitigate this risk properly (fire watches, extinguishers, safe zones), but incidents still happen, and insurers increasingly take a close interest in torch-on works.

EPDM installation is flame-free, which reduces risk significantly. Adhesives still require good ventilation and correct handling, but there is no live flame involved.

For homeowners, and especially for occupied buildings, that difference matters.

DIY Installation Feasibility

EPDM (More DIY-Friendly)

EPDM is generally more achievable for competent DIYers on sheds, garages, and small extensions because:

• no flames or heat welding

• fewer layers and steps

• repair materials are accessible

Handling large sheets safely and detailing around edges/outlets are the main challenges, but the system itself is straightforward if instructions are followed properly.

Felt (Not Recommended for DIY)

Torch-on felt isn’t suitable for most DIY installations. The combination of height work, open flame, and seam criticality makes it high risk. Errors are also harder to correct later because problems can be buried within the layers.

Maintenance Requirements Over Time

EPDM Maintenance

EPDM is low maintenance:

• inspect once or twice per year

• clear debris and check drainage

• monitor seams and flashings

Most repairs are simple puncture patches using compatible repair materials. Many small repairs are achievable without specialist tools.

Felt Maintenance

Felt generally needs more attention as it ages:

• oxidation and brittleness increase over time

• cracking and splits become more common

• repairs often require torching and re-layering

Felt roofs can be maintained successfully, but they are typically more demanding long-term.

Weather Performance in Irish Conditions

EPDM in Ireland

EPDM performs very well in Irish conditions:

• constant rain does not degrade the rubber

• good UV resistance

• flexibility accommodates building movement well

Wind performance depends heavily on system design (fully adhered generally performs best in exposed locations).

Felt in Ireland

Felt performs well when new and can be robust if installed correctly, but Ireland’s wet conditions can punish small defects. Once water gets into laps or between layers, it can accelerate blistering, delamination, and degradation.

Environmental Impact and Sustainability

EPDM is generally considered more favourable long term because:

• longer service life (fewer replacements)

• potential recyclability depending on facilities available

• relatively clean rainwater runoff compared to bituminous products

Felt is petroleum-based and is typically disposed of as waste. Some systems can be recycled in specific channels, but landfill is still common.

If sustainability and rainwater harvesting matter, EPDM is often a better fit.

Repair Ease When Problems Occur

• EPDM repairs: patches and seam repairs are generally quick and clean

• Felt repairs: usually require torch application and more specialist skill

The big difference is frequency: EPDM roofs typically need fewer repairs over their lifespan than felt roofs.

Making Your Decision

Choose EPDM if:

• you want long-term value and minimal disruption

• you’re planning to keep the building for 15+ years

• you want a flame-free installation method

• low maintenance matters

• you may install solar or green roof systems later

Choose Felt if:

• the upfront budget is the overriding factor

• it’s a short-term or temporary building solution

• you want a traditional multi-layer build-up

• you’re using an experienced contractor and accept the replacement cycle trade-off

For most Irish property owners planning to hold the building long term, EPDM usually delivers better value despite the higher initial cost.

FAQs

Can EPDM be installed over existing felt roofing?

Sometimes, yes, if the existing felt is dry, stable and properly bonded. Blistered, wet, or delaminated areas must be removed and repaired first. Many installers prefer adding a separation layer or overlay board to create a clean substrate for adhesion.

Which material performs better long-term in Ireland’s wet climate?

EPDM generally outperforms felt long term in Ireland because it doesn’t oxidise and become brittle in the same way. Felt can still perform well, but it tends to be more sensitive to ageing and moisture-related defects.

Is torch-on felt dangerous for residential properties?

Torch-on installation carries real fire risk, particularly on timber decks and older roofs. A competent contractor with correct safety controls reduces risk significantly, but it’s still a higher-risk installation method compared to cold-applied EPDM.

Does felt provide better insulation than EPDM?

Not in any meaningful way. Both systems are waterproofing layers, not insulation. Thermal performance depends almost entirely on the insulation build-up beneath the waterproofing layer.

Can felt roofs be repaired as easily as EPDM?

No. EPDM repairs are typically simpler and require fewer tools. Felt repairs often involve torching, which is more specialised and less DIY-friendly.

Source Quality EPDM Materials from QBM

If you’re leaning toward EPDM over felt for your flat roof project, QBM supplies high-quality EPDM membranes in multiple thickness options to suit domestic and commercial roofs across Ireland. We can also advise on quantities, compatible accessories, and system design considerations to help you get long-term performance from your installation.

Contact QBM today to discuss your project and source EPDM materials built for decades of reliable waterproofing.

Related Articles:

• Pros & Cons Of EPDM Roofing

• Can You Walk On An EPDM Roof