Felt is one of the best-known flat-roof coverings in the UK, but it is no longer the only mainstream option. Homeowners replacing a leaking garage, extension, porch or dormer roof may also be offered EPDM rubber, GRP fibreglass, single-ply membranes or a liquid-applied waterproofing system.
Each material has its own strengths. EPDM can provide a flexible membrane with relatively few field joints. GRP creates a hard, seamless surface. Single-ply systems offer lightweight waterproofing, while liquid products can suit roofs with awkward shapes and complicated details.
Despite these alternatives, modern felt roofing remains widely used. Today’s reinforced bitumen systems are very different from the thin roll felt often found on garden sheds. Professionally specified felt can create a strong, multi-layer waterproof covering suitable for new roofs and refurbishment projects.
This guide compares the main felt roof alternatives, their advantages and limitations, and the reasons many UK homeowners and roofing contractors still choose felt.
What is modern felt roofing?
The term “felt roof” can refer to several different products.
Basic shed felt usually consists of a relatively thin bitumen sheet supplied in rolls. In contrast, professional flat-roofing systems use reinforced bituminous membranes designed as part of a complete waterproof build-up.
A modern felt system may include:
- a roof deck
- a vapour-control layer
- insulation
- an underlay membrane
- an intermediate layer
- a mineral-finished cap sheet
The layers may be installed using:
- torch bonding
- hot bitumen
- cold adhesive
- self-adhesive backing
- mechanical fixing
- a combination of these methods
BMI describes multi-layer bituminous waterproofing as a robust and versatile solution for warm, cold and inverted flat roofs. Its UK systems include products carrying guarantees of up to 20 years, subject to the specified system and installation requirements.
Main alternatives to felt roofing
The most common alternatives considered for domestic flat roofs are:
- EPDM rubber roofing
- GRP fibreglass roofing
- PVC or FPO single-ply membranes
- liquid-applied waterproofing
- metal roofing
- green-roof systems installed over a suitable waterproof layer
For most garages and domestic extensions, homeowners mainly compare felt with EPDM and GRP.
Quick comparison of flat-roof materials
| Roofing system | Main characteristic | Typical appeal | Possible limitation |
|---|---|---|---|
| Reinforced felt | Multi-layer bitumen membrane | Durable, familiar and repairable | Heat application may be used |
| EPDM | Flexible rubber sheet | Long sheet sizes and few field joints | Detailing and adhesive preparation matter |
| GRP fibreglass | Rigid resin and glass-fibre laminate | Seamless hard finish | Installation is weather and temperature sensitive |
| Single ply | Lightweight polymer membrane | Fast installation and modern specification | Usually specialist-installed |
| Liquid roofing | Fluid membrane cured in place | Suits complex shapes and details | Surface preparation and thickness are critical |
| Metal | Aluminium, zinc or coated steel covering | Long-lasting architectural finish | Higher cost and specialist detailing |
| Green roof | Vegetation over a waterproof system | Appearance, biodiversity and rainwater benefits | Extra structural, drainage and maintenance requirements |
Alternative 1: EPDM rubber roofing
EPDM stands for ethylene propylene diene monomer. It is a synthetic rubber membrane used on domestic and commercial flat roofs.
For smaller roofs, it may be supplied as one large sheet. This can reduce the number of seams across the open roof area, although joints and detailing are still required at edges, outlets, pipes and rooflights.
Advantages of EPDM
- flexible membrane
- large sheets can reduce field seams
- no gas torch needed for standard installation
- resistant to ultraviolet exposure
- relatively lightweight
- suitable for many garages, sheds and extensions
- straightforward to repair with compatible materials
- available in complete DIY kits for smaller outbuildings
EPDM suppliers commonly describe an anticipated service life of 50 years or more when the membrane is correctly specified and installed. This is a manufacturer or supplier expectation rather than a guarantee that every domestic installation will achieve that lifespan.
Possible disadvantages of EPDM
- surface preparation must be thorough
- adhesives require suitable weather conditions
- wrinkles may remain if the sheet is positioned poorly
- corners and outlets require careful detailing
- the plain rubber appearance may not suit every homeowner
- punctures can occur through careless foot traffic
- repairs should use compatible EPDM products
- complex roofs may require several sheets and additional seams
EPDM may suit:
- simple rectangular garage roofs
- garden rooms
- extensions with few penetrations
- homeowners who prefer flame-free installation
- roofs where one large membrane can cover most of the surface
Alternative 2: GRP fibreglass roofing
GRP means glass-reinforced plastic. The system usually involves laying resin and glass-fibre reinforcement over a suitable timber deck, followed by a protective topcoat.
Once cured, it forms a hard, continuous waterproof surface.
Advantages of GRP
- seamless surface across the main roof area
- hard and rigid finish
- neat perimeter trims
- available in different topcoat colours
- can suit balconies or walkways when the correct traffic-grade specification is used
- complex corners can be laminated into the system
CrysticROOF’s accredited systems include specifications offering 20- or 25-year guarantees when installed by approved contractors using the required materials and procedures.
Possible disadvantages of GRP
- deck movement can lead to cracking
- installation is sensitive to rain and temperature
- resin requires accurate mixing
- poor consolidation can leave weak areas
- strong odours may occur during installation
- the deck usually needs to be very clean, dry and stable
- repairs can remain visible
- large roofs require careful movement detailing
GRP may suit:
- small and medium-sized domestic roofs
- roofs with a sound new timber deck
- homeowners wanting a hard, smooth finish
- roof shapes that can be laminated without excessive movement joints
Alternative 3: single-ply roofing
Single-ply roofs use one principal waterproof membrane, commonly manufactured from PVC, FPO or a related polymer.
Sheets are generally mechanically fixed, adhered or otherwise secured, while joints are usually hot-air welded.
Single-ply systems are used extensively on commercial buildings, although they may also appear on larger domestic extensions and contemporary homes.
Advantages of single ply
- lightweight construction
- relatively fast installation
- clean and modern appearance
- flame-free hot-air-welded seams
- can support some green-roof and solar installations
- reflective finishes may be available
- suitable for new-build and refurbishment work
Bauder describes single-ply systems as lightweight and suitable for fast-track construction. It also lists flame-free installation, ultraviolet resistance and recyclability among their benefits.
Possible disadvantages of single ply
- usually needs a trained specialist installer
- membrane can be punctured by sharp objects
- detailing quality is critical
- small domestic jobs may have relatively high setup costs
- repairs need compatible welding or patching
- not every local domestic roofer installs it
Single ply may suit:
- modern extensions
- larger domestic flat roofs
- lightweight structures
- roofs intended to support solar panels or green-roof systems
- projects already designed around a manufacturer-backed system
Alternative 4: liquid-applied roofing
Liquid waterproofing is brushed, rolled or sprayed onto the roof. It then cures to form a continuous membrane.
Products may use:
- polyurethane
- PMMA
- acrylic
- bitumen-based formulations
- other resin technologies
Some systems include reinforcement fabric, particularly around joints and details.
Advantages of liquid roofing
- seamless finish
- useful around pipes and awkward shapes
- can reduce the need for numerous cut membrane pieces
- often installed without flame
- may suit refurbishment and local detailing
- can be used on balconies, gutters and complex roof junctions where approved
BMI describes liquid waterproofing as useful for both new-build and refurbishment projects, while Bauder identifies cold-applied liquid systems as particularly useful where roofs contain complex detailing or restricted access.
Possible disadvantages of liquid roofing
- substrate preparation is extremely important
- wet or unstable roofs should not simply be coated
- installers must achieve the required thickness
- curing depends on weather and product type
- some low-cost coatings are maintenance products rather than complete roof systems
- defects beneath the coating may remain hidden
Liquid roofing may suit:
- balconies
- gutters
- roofs containing numerous penetrations
- awkward junctions
- refurbishment where the existing substrate is proven suitable
Alternative 5: metal flat or low-pitched roofing
Some low-pitched roofs use aluminium, zinc, copper or coated steel.
Metal systems can provide a distinctive appearance and a long service life, but they differ greatly from conventional domestic felt roofing.
Advantages of metal
- durable finish
- architectural appearance
- relatively lightweight
- recyclable materials
- suitable for certain very low-pitched systems
- standing seams can create strong linear detailing
Possible disadvantages
- higher initial cost
- installation requires specialist skills
- rain noise may need consideration
- condensation control is essential
- thermal expansion must be accommodated
- intricate roofs can become expensive
Metal is more commonly selected as part of an architectural renovation or new-build design than as a basic garage-roof replacement.
Alternative 6: green roofing
A green roof includes vegetation, growing medium, drainage and protection layers over a suitable waterproof membrane.
The waterproof layer may itself be made from felt, EPDM, single ply or another root-resistant system. Therefore, a green roof is not always an alternative waterproofing material by itself; it is a complete roof arrangement built above the membrane.
Advantages of green roofs
- improved appearance
- biodiversity benefits
- some rainwater retention
- added protection for the waterproof membrane
- potential thermal and acoustic benefits
Possible disadvantages
- additional structural load
- drainage design requirements
- maintenance
- higher upfront cost
- need for root-resistant waterproofing
- more complicated leak investigation
Bauder notes that modern flat roofs can incorporate green roofs to support biodiversity and reduce rainwater runoff.
Felt roofing compared with EPDM
| Factor | Reinforced felt | EPDM |
| Main material | Modified bitumen membrane | Synthetic rubber |
| Typical system | Multi-layer | Often one principal sheet |
| Installation | Torch, adhesive, self-adhesive or mechanical fixing | Adhesive and mechanical edge details |
| Seams | More seams in multi-layer system | Fewer on simple small roofs |
| Flexibility | Good with modern modified membranes | Highly flexible |
| Appearance | Mineral or smooth bitumen finish | Plain rubber surface |
| Local repairs | Familiar to many roofers | Requires compatible EPDM patches |
| Complex details | Strong when built up correctly | Requires formed accessories and careful bonding |
| Flame-free options | Available | Standard installation is normally flame-free |
| DIY suitability | Basic shed felt only | Small-roof kits are widely available |
| Contractor availability | Very widespread | Widely available but not universal |
Which is better?
EPDM may appeal where a large uninterrupted sheet can cover a simple roof. Felt may provide greater familiarity and versatility where there are several upstands, outlets and complicated edge details.
The quality of the installer and underlying roof design will normally matter more than choosing one material based on marketing claims alone.
Felt roofing compared with GRP
| Factor | Reinforced felt | GRP fibreglass |
| Surface | Flexible membrane system | Hard, rigid laminate |
| Joints | Overlapped membrane seams | Seamless field surface |
| Movement tolerance | Can accommodate some movement | Deck movement can cause cracking |
| Installation conditions | Product-dependent | Particularly sensitive to rain and curing temperature |
| Finish | Mineral or smooth | Smooth coloured topcoat |
| Repairs | Patches can integrate with felt | Repairs involve sanding and re-laminating |
| Deck requirement | Must be sound and suitable | Requires particularly stable, well-prepared deck |
| Complex shapes | Built up using membrane detailing | Can be moulded around shapes |
| Noise and odour | Torch or bitumen odours may occur | Resin odour may occur |
Which is better?
GRP may suit a stable, newly decked roof where the homeowner wants a hard, seamless finish. Felt may be preferable where flexibility, layered protection and familiar repair methods are priorities.
Felt roofing compared with single ply
| Factor | Reinforced felt | Single ply |
| Waterproof layers | Usually multiple | One principal membrane |
| Weight | Moderate | Lightweight |
| Seam method | Heat, adhesive or bitumen bonding | Usually hot-air welding |
| Domestic availability | Very widespread | More specialist |
| Complex detailing | Established built-up details | Manufacturer-specific accessories and welding |
| Foot traffic tolerance | Reinforced systems can be robust | Requires protection where regularly accessed |
| Typical use | Domestic and commercial | Common on larger commercial and modern projects |
Single ply may offer advantages on lightweight, large or architect-designed roofs. Felt often remains easier to source for conventional domestic garages and extensions.
Felt roofing compared with liquid systems
| Factor | Reinforced felt | Liquid membrane |
| Form | Pre-manufactured sheets | Applied as a liquid |
| Main joints | Overlaps between sheets | Seamless once cured |
| Thickness | Controlled by manufactured membrane | Depends on application rate |
| Detailing | Cut and bonded membrane pieces | Flows around complex details |
| Substrate defects | May be visible during installation | Can be concealed if assessment is poor |
| Weather sensitivity | Product-dependent | Often highly dependent on curing conditions |
| Repairs | Compatible patches | Clean, prime and recoat |
Liquid products can be excellent for detailed roofs, but homeowners should distinguish between an accredited waterproofing system and a low-cost roof paint intended mainly for maintenance.
Why do people still choose felt roofing?
The number of alternatives might suggest that felt is outdated. In reality, modern reinforced felt continues to offer several practical advantages.
1. Felt is a proven and familiar system
Bituminous membranes have been used on flat roofs for many years. Most established flat-roofing contractors understand how to:
- inspect felt
- strip it
- repair local defects
- form overlaps
- waterproof upstands
- detail outlets
- install perimeter trims
- add further layers where suitable
This broad knowledge can make it easier to obtain competitive quotations and future repairs.
2. Modern felt is much stronger than basic shed felt
Professional felt systems use reinforcement and modified bitumen to improve strength, flexibility and weather resistance.
BMI notes that SBS-modified bitumen provides good resistance to weather and loading and is popular in the UK.
Homeowners should avoid comparing a professional multi-layer roof directly with a roll of lightweight garden-building felt.
3. Multi-layer construction provides redundancy
A properly installed built-up felt roof may contain several waterproof layers.
If the cap sheet suffers minor surface damage, the layers below may continue protecting the deck while repair is arranged. This does not mean damage can be ignored, but the layered system can provide resilience.
BMI promotes multi-layer bituminous waterproofing for its durability and versatility across several flat-roof constructions.
4. Felt handles complex roof details well
Domestic roofs often contain:
- rooflights
- soil pipes
- wall junctions
- chimney details
- parapets
- internal outlets
- unusual corners
- transitions into pitched roofing
Experienced felt roofers can cut and layer membrane around these areas. Multiple layers can also reinforce vulnerable details.
5. Repairs are straightforward for many roofers
A local split or open seam can often be repaired with compatible bitumen membrane or a cold-applied system.
Because felt remains common, homeowners are less likely to depend on one specialist manufacturer or installer for every future repair.
6. It can be cost-effective
Felt is often competitively priced compared with some premium GRP, liquid, metal and manufacturer-backed single-ply systems.
The final cost depends more on:
- roof area
- access
- decking
- insulation
- drainage
- rooflights
- upstands
- specification
A basic felt quotation may be cheaper because it includes less work. Therefore, compare the complete roof build-up rather than material names alone.
7. Felt suits many different roof constructions
Reinforced bitumen systems can be specified for:
- warm roofs
- cold roofs
- inverted roofs
- refurbishment
- new construction
- timber decks
- concrete decks
- some metal substrates
This flexibility helps explain its continued use across both domestic and commercial projects.
8. Different installation methods are available
Although felt is often associated with torch-on application, modern systems can also use:
- cold adhesive
- self-adhesive layers
- mechanical fixing
- hot-air-assisted methods
- flame-free detailing around vulnerable areas
BMI lists torch-applied, adhesive and mechanically fixed methods for bituminous membrane systems.
This means felt does not always require open-flame application across every part of a roof.
9. Reinforced felt can tolerate normal maintenance access
Some reinforced bitumen systems can cope with limited foot traffic associated with inspection and maintenance.
Bauder identifies the ability to sustain maintenance-related traffic and rooftop loads as an advantage of reinforced bitumen membrane systems.
Regular access should still use suitable walkways or protection where required.
10. Mineral finishes provide a familiar appearance
Mineral cap sheets are available in several finishes, although charcoal remains common.
The textured surface may blend well with:
- traditional extensions
- garages
- dormer roofs
- bay windows
- parapets
- existing bituminous details
Some homeowners prefer this appearance to smooth black rubber or glossy fibreglass.
11. Felt can be used for local repair and full systems
Bituminous products range from temporary repair compounds to manufacturer-backed multi-layer roofing systems.
This makes felt useful throughout the roof’s lifecycle:
- local patches
- seam repair
- upstand renewal
- partial replacement
- overlay where appropriate
- full strip and replacement
12. Contractor availability is strong
Many UK roofing businesses have experience with felt roofing. That can make it easier to:
- obtain multiple quotations
- arrange emergency repairs
- find maintenance support
- replace a limited section
- inspect an older installation
Installer competence still varies, so familiarity alone should not determine the choice.
Why some homeowners choose an alternative instead
Felt will not suit every project.
A homeowner may choose EPDM because:
- the roof is a simple rectangle
- one large sheet can reduce field joints
- flame-free fitting is important
- a long manufacturer-stated life expectancy is attractive
GRP may be selected because:
- a hard finish is preferred
- the roof has a stable new deck
- a seamless appearance is important
- matching trims create a neat edge
Single ply may be chosen because:
- the structure needs a lightweight membrane
- the project uses a modern commercial-style specification
- fast installation is important
- the roof supports solar or green-roof features
Liquid waterproofing may suit:
- numerous complex penetrations
- awkward gutters
- balconies
- areas where sheets would require many cuts
- refurbishment with restricted access
Typical lifespan comparison
Lifespan figures should be treated cautiously. Installation, drainage, exposure and maintenance can make a greater difference than the headline material claim.
| System | Broad commonly stated service range | Important qualification |
| Basic shed felt | 5–10 years | Product quality varies greatly |
| Reinforced built-up felt | 15–30+ years | Depends on system, installation and maintenance |
| EPDM | 30–50+ years | Supplier claims often assume correct installation |
| GRP | 20–30 years | Deck movement and workmanship are critical |
| Single ply | 20–35+ years | Depends on membrane and specification |
| Liquid system | 10–25+ years | Product type and application thickness vary widely |
| Metal | 30–60+ years | Detailing, finish and environment affect durability |
Specific systems may carry shorter or longer guarantees than these broad ranges. A guarantee is not always the same as expected service life.
Typical cost comparison
The figures below are broad UK planning ranges for professional domestic work. They should not replace measured quotations.
| Roof covering | Broad installed cost per m² |
| Reinforced felt | £70–£140+ |
| EPDM | £80–£150+ |
| GRP fibreglass | £90–£160+ |
| Single ply | £100–£180+ |
| Liquid waterproofing | £80–£180+ |
| Architectural metal | £150–£300+ |
Small roofs can cost more per square metre because scaffolding, outlets, trims and travel costs apply regardless of roof size.
The quotation may also need to include:
- old covering removal
- new decking
- insulation
- vapour control
- improved falls
- outlets
- rooflights
- wall flashings
- fascia repairs
- waste disposal
- VAT
Which roof covering suits different projects?
| Project | Options often considered |
| Small timber shed | Shed felt, EPDM kit or corrugated sheet |
| Detached garage | Reinforced felt, EPDM or GRP |
| Heated house extension | Reinforced felt, EPDM, GRP or single ply |
| Roof with many pipes and details | Felt or liquid waterproofing |
| Large modern extension | Single ply, EPDM, felt or GRP |
| Balcony or occasional walkway | Traffic-grade GRP or specified liquid system |
| Green roof | Root-resistant felt, EPDM or single-ply system |
| Period-property extension | Mineral felt, metal or another finish suited to the design |
Questions to ask before selecting a material
Ask each contractor:
- Why does this system suit my roof?
- Is the deck suitable?
- Will the old roof be stripped?
- Is the insulation wet?
- How will roof falls be improved?
- How many joints will the system have?
- How will rooflights and outlets be detailed?
- Will installation use a gas torch?
- What flame-free alternatives are available?
- What manufacturer and product range will be used?
- Is the installer trained or approved for that system?
- What maintenance does the roof require?
- How are future repairs completed?
- What product and workmanship guarantees apply?
- Does the quotation include access, disposal and VAT?
Comparing flat-roof quotations
| Quote item | Roofer A | Roofer B | Roofer C |
| Roofing system | |||
| Manufacturer | |||
| Roof area | |||
| Existing roof removed | |||
| Deck replacement allowance | |||
| Insulation specification | |||
| Drainage improvements | |||
| Number of membrane layers | |||
| Rooflight details | |||
| Upstands and trims | |||
| Installation method | |||
| Product guarantee | |||
| Workmanship guarantee | |||
| Waste and access | |||
| VAT included | |||
| Total price |
Material choice matters less than roof design and workmanship
A premium membrane will not compensate for:
- rotten decking
- inadequate roof falls
- blocked drainage
- low upstands
- poor outlet detailing
- wet insulation
- missing vapour control
- badly sealed joints
- careless installation
Likewise, a properly designed reinforced felt roof can outperform a poorly installed alternative.
The best quotation should explain the complete system rather than simply naming the visible roof covering.
Common misconceptions about felt and its alternatives
“Rubber has no seams”
A simple EPDM roof may use one main sheet, but it still requires seams or bonded details at trims, pipes, outlets and extensions to the membrane.
“GRP can never leak because it is seamless”
GRP can still fail at trims, outlets, rooflights, cracks or areas where the deck moves.
“Felt always lasts only ten years”
This may apply to some lightweight shed products. Professionally installed reinforced systems are substantially different and may carry manufacturer guarantees of up to 20 years depending on specification.
“Liquid roofing can be painted over any old roof”
Liquid systems require a suitable, prepared substrate. Applying a coating over wet insulation or rotten decking does not create a sound roof.
“The most expensive material is always best”
Roof complexity, drainage, installer skill and maintenance may matter more than the highest-priced membrane.
Is felt still a good choice?
Felt remains a sensible option where:
- a proven multi-layer system is preferred
- the roof has complex details
- local contractor availability matters
- future repairs should be straightforward
- a mineral finish suits the building
- the budget does not justify a premium specialist system
- an accredited reinforced bitumen specification is available
An alternative may offer better value where the roof design strongly suits that material. For example, one-piece EPDM can work well on a simple garage, while GRP may suit a small stable roof requiring a hard finish.
The decision should follow an inspection rather than a general claim that one material is always superior.
Request flat-roof replacement quotes
When requesting quotes, provide:
- roof dimensions
- building type
- whether the space below is heated
- current roof material
- known leaks or ponding
- number of rooflights and outlets
- parapets and wall junctions
- access restrictions
- previous overlays or repairs
- preferred materials, if any
Find Me Quotes can connect homeowners with local flat-roofing specialists who install felt, EPDM, GRP and other waterproofing systems.
Comparing several written specifications can help you understand which material suits the roof, what preparation is included and whether the contractor has allowed for decking, insulation and drainage work.
Frequently asked questions about felt roof alternatives
What is the most popular alternative to felt roofing?
EPDM rubber and GRP fibreglass are among the most common alternatives for domestic garages and extensions. Single-ply and liquid systems are also widely used, particularly on larger or more complex projects.
Is EPDM better than felt?
EPDM can suit simple roofs because large sheets reduce the number of field joints. Felt may offer advantages on roofs with complex details and provides a familiar multi-layer system. Installation quality remains critical for both.
Is fibreglass roofing better than felt?
GRP creates a hard, seamless finish, while felt provides a flexible layered membrane. GRP needs a stable, well-prepared deck, whereas felt can suit a wider variety of established roof details.
Why is felt roofing still popular?
Felt remains popular because it is familiar, versatile, repairable, widely available and often cost-effective. Modern reinforced systems are considerably stronger than basic shed felt.
Does felt roofing always require a gas torch?
No. Some systems use cold adhesive, self-adhesive membranes or mechanical fixing. Torch application remains common, but flame-free methods and details are available.
Which flat-roof material lasts longest?
Manufacturers and suppliers often state long lifespans for EPDM, while high-quality felt, GRP and single-ply systems can also provide decades of service. Roof design, installation and maintenance strongly affect the result.
Is a seamless roof always better?
Not necessarily. Seamless surfaces remove some joints, but leaks can still occur at outlets, trims, penetrations and cracks. A well-installed jointed system can provide reliable long-term performance.
Can felt roofing support a green roof?
Yes, provided the complete waterproofing system is designed and approved for the purpose, including root resistance, drainage, protection and structural loading.
