Diss Roofers installs and repairs flat roofs on extensions, garages and outbuildings in Eye and the surrounding area, using felt and EPDM rubber systems that are built to last.
Call any time. Calls are answered day and night and passed straight to our roofers.
A flat roof is never truly flat. Every system is laid with a slight fall, typically a minimum of 1:80, so rainwater drains away from the centre of the deck toward outlets or an edge drip. Without that fall, water pools, and pooling water is the single most common cause of premature failure across all flat roof types.
The deck beneath the waterproofing layer matters as much as the surface material. Older roofs often sit on timber joists with tongue-and-groove boarding or plywood. If the deck has softened or deflected over the years, laying a new surface over it will not cure the underlying problem. A proper survey checks for movement, rot and the condition of any existing insulation before work begins.
Two systems suit the majority of domestic flat roofs: built-up felt and EPDM rubber. Each has different strengths, and the right choice depends on the size of the roof, the budget and how accessible the surface is for future checks.
Both systems can be installed with either warm-roof or cold-roof insulation configurations. A warm roof, where insulation sits above the deck, is now the standard approach for new work and full replacements because it removes the risk of condensation forming within the roof structure.
Most flat roof failures have straightforward causes. Knowing what they are helps you spot a problem early and have an informed conversation with a roofer.
This is the question homeowners ask most often, and the honest answer is that it depends on the age and overall condition of the existing system. A patch repair on a roof that is already 20 years old with widespread crazing may hold for a season but is unlikely to see out another five years without further work.
A repair makes sense when the rest of the system is sound and the problem is genuinely isolated. A single lifted lap, a cracked flashing or a blocked outlet can all be repaired without disturbing the rest of the surface. When defects are spread across the whole area, or when the deck itself has deteriorated, a full replacement is the more economical option over a five-year view.
Typical flat roof replacement costs in the UK run from around £70 to £120 per square metre for a built-up felt system and from around £80 to £130 per square metre for EPDM, depending on access, deck condition and whether the insulation is being upgraded. A garage or single-storey extension roof of around 20 square metres would therefore cost roughly £1,400 to £2,600 installed, though prices vary with the specifics of each job.
Ask any roofer to show you what they found on the deck during strip-off before they lay the new system. If they cannot show you photographs or are reluctant to discuss what was underneath, that is worth pressing on.
This is the section most homeowners never receive enough information about. A flat roof installed well and then ignored will fail earlier than it needs to. A flat roof installed well and checked twice a year will comfortably reach the upper end of its expected lifespan. The maintenance involved is genuinely simple and takes less than an hour twice a year.
The best times to check are in autumn, after leaves have fallen, and in early spring after the frosts have finished. You do not need to get on the roof to do a useful inspection. Most of what matters is visible from a ladder at the edge.
Moss and algae grow on mineral-surfaced felt roofs, particularly on north-facing surfaces or surfaces shaded by trees. Left in place, moss retains moisture against the surface, accelerates weathering and can eventually lift the mineral granules from the cap sheet. Clearing it promptly matters.
Brush loose moss off gently with a stiff brush, working toward the outlet so debris does not block it. Do not use a pressure washer on felt roofing: the force strips the surface granules and forces water into any small crack or lap. A biocide wash appropriate for roofing surfaces will kill the residual growth and slow regrowth. Apply it according to the manufacturer's instructions and allow it to work before brushing again.
EPDM rubber membranes are far less susceptible to moss because the surface does not hold moisture in the same way as granulated felt. Occasional brushing and a rinse with clean water is usually sufficient to keep an EPDM surface clear.
A small damp patch on a ceiling below a flat roof will not resolve itself. The leak source is almost always some distance from where the water appears inside, because water travels along joists before dropping. A stain that appears in wet weather and dries out afterwards is still a live leak: the fact that it stops does not mean the entry point has sealed. Every wet-weather leak should be investigated promptly because the damage to the deck and insulation compounds with each episode.
Blistering on a felt surface deserves attention even when it has not yet split. A blister that is visibly growing between inspections means moisture is present within the system. If a blister splits open during a dry spell, water enters freely the next time it rains. A roofer can cut out an isolated blister and re-bond the area as a repair before it becomes a larger problem.
Frost affects flat roofs in two ways. It can open up existing small cracks in aged felt by expanding any moisture held within them, and it can damage sealants around penetrations that have already started to harden with age. After a hard frost or a prolonged cold spell, add a check of the sealant around any rooflights, pipes and flashings to your inspection list. Any sealant that has become brittle, cracked or has pulled away from the substrate should be replaced rather than patched over the top.
Overhanging branches drop debris onto the roof and shade sections of it, encouraging moss. Where it is practical, cut back overhanging vegetation so the whole roof surface gets reasonable light and air. Roots from nearby trees and self-seeded plants can also establish themselves in the mineral layer of older felt roofs; remove any seedlings by hand as soon as they appear rather than letting roots develop.
Clearing gutters and outlets, removing moss with a biocide and keeping the surface free of debris are all tasks a careful homeowner can do safely from a ladder at the edge. Walking on the roof surface itself to investigate or carry out repairs is a different matter: felt surfaces can be slippery when wet and the deck may be less sound than it looks from above, particularly on older roofs. Any repair that involves cutting into the membrane, re-bonding a flashing or re-laying sections of the system should be carried out by a roofer with the right materials and experience.
If you are in Eye or the surrounding area and you have spotted something during your inspection that you are not sure about, call us for a flat roof survey. We can tell you whether the problem needs attention now, can wait until the next inspection or requires more urgent work.
Before agreeing to flat roofing work, it is worth asking the roofer:
A roofer who answers these questions clearly and without hesitation is one who knows what they are doing. Vague answers or pressure to decide quickly are both reasons to seek a second opinion.
Whether your roof is leaking, you have spotted blistering or lifted laps, or you simply want a professional check before winter, call Diss Roofers to arrange a flat roof survey in Eye. We will assess the deck, the waterproofing and the drainage and give you a clear picture of what the roof needs.
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Call any time. Calls are answered day and night and passed straight to our roofers.
