When a roof leak or slipped tiles appear in March, getting the right repair done properly the first time saves money and prevents damage spreading through the rest of the property.
Call any time. Calls are answered day and night and passed straight to our roofers.
A roof repair can mean anything from sealing a single cracked tile to stripping back a felt flat roof and relaying the whole surface. The scope of the work depends on the material, the age of the roof, and how far the problem has travelled. Water rarely enters where it appears on the ceiling below, so a proper repair starts with finding the true source rather than treating only the obvious symptom.
On pitched roofs, common repairs include replacing broken or slipped slates and tiles, repointing or replacing the ridge, repairing or replacing lead, zinc or aluminium flashing around chimneys and abutments, resealing verge mortar, and clearing or reseating blocked gutters where overflow is soaking the fascia. On flat roofs, the work is different in almost every respect, which is why we cover flat roof repairs separately below.
Flat roofs on extensions, garages, bay windows and outbuildings are among the most frequently repaired surfaces a roofer works on. The material the roof is made from determines what repair options are available, how long those repairs are likely to last, and whether a repair is genuinely worth doing or whether a full replacement makes more sense. This is where most homeowners benefit from honest information before any money changes hands.
Flat roofs are most often one of three types: traditional built-up felt, modern EPDM rubber membrane, or occasionally torch-on mineral felt. Each behaves differently, fails in different ways, and responds to repair differently.
Traditional built-up felt roofing is made from layers of bitumen-impregnated felt bonded together, usually in two or three layers. It has been a common flat roof material for many years. The material is not inherently poor, but it does have a finite lifespan, and understanding what causes it to fail helps you decide whether a repair will hold.
Split or cracked felt is one of the most common problems. As bitumen ages it loses its flexibility, becomes brittle, and cracks - particularly after frost. A split felt surface will allow water straight through to the deck below. Short splits of up to a few hundred millimetres can often be repaired by cleaning back the area, applying a compatible bonding compound and overlaying a patch of new felt. The patch must extend well beyond the split in every direction to seal properly. A surface covered in fine crazing or multiple splits across a large area is a different matter - patching every crack rarely gives a lasting result.
Blistered or bubbled felt occurs when moisture or air becomes trapped between layers during installation or later works its way in. As the sun heats the surface, the trapped moisture turns to vapour and forces the felt upward into blisters. Small blisters that are still intact can sometimes be left alone if they are not leaking, but a blister that has burst will allow water in and must be repaired. The repair involves carefully cutting the blister, allowing it to dry thoroughly, then bonding it down and patching over it. Blistering that covers a significant area of the roof often points to a systemic moisture problem between layers, at which point a full re-felt is typically the more cost-effective long-term answer.
Failed felt seams and laps happen where two sheets of felt overlap and the bond between them breaks down over time. Water tracking under an open lap can travel a considerable distance before it appears inside the building. Seam repairs involve carefully lifting the open edge, cleaning and drying both surfaces, applying fresh bonding compound, and pressing the lap back down. Getting this right requires dry conditions and adequate curing time - a repair done in damp or cold weather on a felt seam rarely bonds as it should.
Loose felt edges and upstands are very common on older flat roofs. Where the felt turns up against a parapet wall, a fascia board or a step in the structure, it is finished with an upstand. If the upstand detaches - which often happens as the felt shrinks with age or as the fixing batten rots - rainwater runs straight behind it and into the wall or roof structure. Repairing this properly means refixing or replacing the batten, trimming back any damaged felt, and bonding a new upstand strip that reaches high enough up the wall to keep driven rain out. A short upstand of less than 150mm is an invitation to future leaks.
Leaking flashing and wall junctions where the flat roof meets a brick wall are a separate issue from the felt surface itself. The flashing - usually lead or zinc - can lift, crack, or pull away from the wall over time. If the flashing is in otherwise good condition, it can often be reseated into the mortar joint and sealed. Where the flashing itself has split or corroded significantly, replacing that section is the more reliable answer.
Rooflights and lanterns fitted in flat roofs are a frequent source of leaks. The seal between the upstand kerb and the felt can fail, or the glazing frame itself can crack or allow water past the seal. Diagnosing whether the water is entering through the felt or through the rooflight frame matters, because each requires a different repair approach.
Leaks around pipes, vents and flues that pass through a flat roof are another common entry point. The collar or flashing around a pipe needs to be bonded tightly to both the pipe and the felt surface. These collars harden and crack over time, especially on south-facing roofs where UV exposure is strongest.
Ponding water on a felt roof is a sign that the roof is not draining correctly. Some ponding after heavy rain is normal and clears within 24-48 hours. Water that sits for days or weeks accelerates the breakdown of the felt surface and adds weight to the roof structure. The solution may be as simple as clearing a blocked outlet, or it may require improving the fall of the roof - which is a more significant piece of work than a straightforward repair.
EPDM (ethylene propylene diene monomer) rubber roofing has become the preferred flat roof material for new installations and replacements over the past fifteen years or so. It is a single-ply membrane, typically 1.2mm or 1.5mm thick, bonded to the deck in large sheets with very few seams. A well-installed EPDM roof has considerably fewer weak points than a traditional felt roof, which is one of its main practical advantages.
When EPDM does develop a problem, it is almost always at a seam, at a penetration (pipe or vent), at the edge detail, or at a point where something has physically punctured or torn the membrane. Small tears and punctures in EPDM can be repaired cleanly using compatible EPDM tape and lap sealant. The repair is bonded chemically to the existing membrane rather than simply sitting on top of it, so when it is done correctly it tends to be very durable. The key condition is that the membrane must be completely clean and dry before the repair tape is applied - even condensation on the surface can prevent proper adhesion.
Failed seams on EPDM roofs, where two sheets were joined, can be re-bonded using seam tape designed for the purpose. Where an EPDM roof has been on for a long time and has multiple small defects spread across the surface, it is worth getting an honest assessment of whether targeted repairs will hold or whether the cost of repeated call-outs over the coming years makes a full replacement the better investment.
Torch-on felt, sometimes called SBS modified bitumen or mineral felt, is a heavier, more durable product than traditional bonded felt. It is applied by heating the underside of the sheet with a gas torch until it flows, then rolling it into place. Repairs to torch-on felt follow broadly the same principles as traditional felt repair - cleaning back, drying, applying a compatible patch material and bonding it in. The difference is that the patch itself should ideally be the same torch-on material, applied properly, rather than a cold-applied sealant spread over the top. A torch-on patch done properly is practically invisible and very secure.
This is the question homeowners ask most often, and it deserves a straight answer rather than a sales pitch. A repair makes sense when the roof is structurally sound, the deck (the boards or concrete below the felt or membrane) is dry and intact, and the defect is isolated. If the deck has softened, if there are multiple failures across the surface, or if the felt is more than 15-20 years old and showing widespread deterioration, repair costs can mount up quickly without addressing the underlying condition of the roof.
A roofer giving you honest advice should be able to tell you the condition of the deck - either by lifting a small area of felt to check, or by pressing the surface to feel for softness - before recommending repair or replacement. If someone quotes for a repair without checking the deck, that is worth questioning.
Full re-felting becomes the better option when: the existing felt has split, blistered or delaminated across more than roughly a third of the roof area; when the deck boards have softened, rotted or deflected; when multiple previous patches have been applied and are themselves starting to fail; or when the roof is over 20 years old and a significant new repair would cost more than a quarter of the replacement cost. In those situations, the money spent on another repair tends to delay the inevitable while adding to the total cost.
On houses with pitched roofs, the most frequent causes of a leak are slipped, cracked or missing tiles or slates, failed pointing on the ridge or hips, deteriorated flashings, and blocked or damaged gutters allowing water to overflow into the wall or soffit. In most cases a pitched roof leak can be isolated and repaired without disturbing the rest of the roof. Replacing a handful of concrete interlocking tiles is straightforward provided a matching tile can be sourced. Natural slate repairs require a little more care - the nail holes and the slate itself need to be sized correctly, and the surrounding slates need to be lifted carefully to avoid cracking them.
Ridge pointing repairs are very common on older properties. The mortar that beds the ridge tiles cracks over time due to thermal movement, and once cracked it allows water to track down behind the ridge. Repointing ridge sections is a targeted repair that, on a roof in otherwise sound condition, can give many years of further service. Where ridge tiles are loose or rocking, they should be fully rebedded rather than pointed over the surface alone.
Flat roof felt repair costs in the March area typically range from around £150-£400 for a straightforward patch repair on a small area, rising to £600-£1,200 or more for larger or more complex repairs involving multiple defects, edge details, or flashing replacement. These figures are for repair work, not full replacement. A full re-felt of a typical garage or small extension roof (say 20-30 square metres) generally runs from around £1,200 to £2,500 depending on the system chosen and the condition of the deck. EPDM replacement costs are generally at the higher end of that range but the material tends to outlast traditional felt significantly.
For pitched roof repairs, a single tile replacement or small patch of repointing might cost £100-£250 as a one-off call-out. Flashing repairs typically range from £200-£600 depending on the length of flashing and the material used. These are typical current UK figures and will vary with the specifics of each job.
Getting two or three quotes on any repair of significant size is sensible. The cheapest quote is not always the worst, but any quote that does not involve the roofer physically getting on the roof to inspect the problem before pricing should be treated with caution.
Can a split felt roof be repaired? A single split or small cracked section can be patched effectively if the surrounding felt and the deck below are in sound condition. A surface with multiple splits or widespread cracking is usually a sign the material has reached the end of its life, and patching each crack becomes a cycle of diminishing returns.
Can blistered roofing felt be repaired? Intact blisters that are not leaking can often be left. Burst blisters must be dealt with to prevent water ingress - the blister is cut, dried out, bonded flat and patched over. Widespread blistering across a roof is better addressed by a full replacement than by patching each one individually.
Is standing water on a felt roof a problem? Water that clears within 24-48 hours after rain is generally not a concern. Water that sits permanently, or for many days after rain stops, accelerates felt deterioration and should be investigated. The fix may be as simple as clearing a drain or it may require improving the fall.
Can a leaking felt roof be repaired in wet weather? Most felt repair systems require a dry, clean surface to bond correctly. Emergency measures - such as temporary sealing compounds or roof repair tape - can stop active water ingress in wet conditions, but these are not permanent repairs. A proper repair should follow once the surface has dried.
Should I repair or replace my felt roof? Repair if the problem is isolated and the deck is sound. Replace if the felt is widely deteriorated, the deck is soft, or the cost of repair is approaching 40-50% of replacement cost. A roofer who checks the deck before advising you is giving you the information you need to make that call.
Will a felt roof repair include damaged roof boards? It depends on what the roofer finds and what is agreed in the quote. Deck replacement adds to the cost and should be discussed and priced before work starts, not presented as an extra once the felt has been stripped. Always ask explicitly whether deck inspection and replacement is included if needed.
When you call, it helps to describe the problem, the type of roof, and roughly how large the affected area is - that way we can give you a realistic sense of what is involved before we attend.
If you have a flat roof that is showing any of the warning signs described above - blistering, open seams, ponding water that does not clear, or a visible drip inside the building - call us for a roof inspection in March. We will tell you honestly whether a repair will solve the problem or whether you are better off planning a replacement.
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Call any time. Calls are answered day and night and passed straight to our roofers.
