Norwich Roofers installs, repairs, and maintains commercial roofs in Loddon and the surrounding south Norfolk area, covering warehouses, retail units, offices, and schools.
A failing commercial roof does not just cause a leak. It can halt production, damage stock, compromise electrical installations, and leave you managing insurance claims instead of running your business. We work with commercial property owners and facilities managers in Loddon and nearby villages to keep roofs watertight, well maintained, and structurally sound.
Our work covers the full range of commercial roofing systems: flat roofing in built-up felt and EPDM rubber membrane, single-ply membranes, and metal sheet roofing for agricultural and industrial buildings. Whether you have a modest retail unit or a large warehouse, we assess what you have, advise on the most cost-effective fix or replacement, and carry out the work with as little disruption to your operation as possible.
Most commercial roof failures do not happen overnight. They develop over months or years, through a combination of material fatigue, poor original installation, and missed maintenance. Knowing what to look for means you can act before a manageable repair becomes a full replacement.
Flat commercial roofs are designed to drain, not to hold standing water. If water is pooling in the same spots after every rain, the roof has either lost its fall or the drainage outlets are blocked or incorrectly positioned. Ponding water accelerates membrane degradation, adds dead load to the structure, and can work its way through even a sound membrane if left long enough.
On built-up felt systems, ponding softens the upper layers and causes them to delaminate. On EPDM and single-ply membranes, persistent standing water attacks the seams and any areas where the membrane has begun to lift. The fix may be as simple as clearing and re-routing drainage, or it may require the installation of additional outlets and re-grading the deck surface beneath the membrane.
Blisters in a flat roof membrane form when moisture or air becomes trapped between the layers during installation, or when the membrane begins to separate from the deck beneath it. They are most visible in summer, when heat causes the trapped air to expand. Left alone, blisters eventually rupture, leaving an open wound in the membrane that lets water in directly.
On older built-up felt roofs, blistering is often a sign that the felt is approaching the end of its serviceable life and that the underlying insulation has been compromised. On EPDM systems, isolated blisters can sometimes be repaired by cutting back the membrane, drying the substrate fully, and re-bonding the affected area. A thorough inspection will tell you which situation you are dealing with before money is spent on the wrong fix.
Thermal movement is one of the main causes of cracking in commercial roofing membranes. A large flat roof expands and contracts with temperature changes, and if the membrane or its detailing cannot accommodate that movement, it cracks. Splits most commonly appear around penetrations such as rooflights, pipework, and upstands, where the membrane has to change direction and is under the most stress.
Open laps, where two sheets of membrane have parted company at the join, are a direct entry point for water. On single-ply systems these joins are heat-welded or solvent-bonded, and a failed weld can look almost invisible from ground level. The first sign is often a water stain on the ceiling below, by which point the insulation underneath may already be saturated. Any open lap or visible split in a commercial roof membrane should be treated as urgent.
Flashings are the metal or membrane details that seal the junction between the roof covering and any vertical surface: parapet walls, chimney stacks, upstands around plant equipment, and abutments with adjacent walls. They are under constant stress from thermal movement and, on older buildings, from mortar joints that have cracked and allowed the flashing to lift.
A common problem is lead or aluminium flashing that has pulled away from the chase cut into the brickwork above, leaving a gap that channels water directly down the wall and into the building. On commercial buildings, failed parapet flashings are a particularly frequent cause of internal water damage because the parapet wall itself acts as a collector, directing any water that gets behind the flashing straight into the roof junction below. Re-fixing and re-sealing flashings is usually a straightforward job, but it needs doing properly with correct fixings and sealant for the material type.
Commercial roofs often have large surface areas with only a small number of drainage outlets. A single blocked outlet on a 500 square metre roof can cause water levels to rise several centimetres in a heavy downpour, loading the structure and forcing water through any weakness in the membrane. Debris build-up, including leaves, moss, and wind-blown material, is the most common cause of blocked outlets.
Outlets themselves can also fail. Cast iron outlets corrode and their clamping rings seize, making it impossible to clear the strainer. PVC outlets can crack in cold weather. Where outlets connect to internal downpipes, the connection point is a frequent source of leaks, particularly in buildings where the roof deck flexes in wind. A proper maintenance programme includes clearing and inspecting outlets at least twice a year, particularly before winter.
Water staining on ceilings and upper walls is the most obvious internal sign of a roof problem, but by the time it appears the leak has usually been running for longer than it looks. Water travels along joists, purlins, and decking before it finds a point where it can drip or seep through, which means the visible stain is rarely directly below the entry point on the roof.
Persistent damp in a commercial space also promotes mould growth, which creates health and safety obligations for the building's occupants and can trigger complaints from staff or tenants. On insulated flat roofs, saturated insulation loses its thermal performance almost entirely, which will show up in higher heating bills before the water damage becomes visible. If a ceiling stain keeps growing or reappears after rain, a roof inspection is the right next step, not another coat of stain-block paint.
A flat roof deck that has started to sag or deflect visibly is a structural concern. On older commercial buildings with timber decks, sagging is usually caused by rotted decking boards or joists, typically the result of a long-running leak that was not caught early enough. On metal deck buildings, deflection can indicate that the deck has corroded through.
Sagging sections must be assessed by someone who can identify whether the problem is limited to the deck surface or extends to the structural supports beneath. In many cases the affected decking can be replaced in sections without requiring a full structural intervention, but this depends on catching the problem before the rot or corrosion spreads laterally. The presence of sag is not something to watch and wait on.
Material age accounts for some failures, but the underlying causes are usually poor initial installation, a lack of maintenance, or alterations made to the building without properly detailing the roof around them. Penetrations for new extraction fans, air conditioning units, or cable runs are a common source of leaks on otherwise sound roofs, because the contractor fitting the equipment did not seal the penetration to the same standard as the original roofing contractor.
Roof traffic is another factor that is underestimated. Maintenance engineers, window cleaners, and plant engineers walking on a flat roof without proper access routes can crack a membrane, crush insulation, or dislodge edge details. Walk pads and defined access routes cost very little compared to the damage an unmanaged roof access regime can cause over a few years.
Finally, re-roofing over an existing system without removing the old membrane is a common corner-cutting practice that shortens the life of the new roof significantly. Moisture trapped between layers continues to degrade both the old and new material from underneath. A new installation should start from a sound, dry, clean deck.
Before any work is agreed, a proper survey of the roof should take place. This means physically walking the roof where it is safe to do so, checking drainage outlets, inspecting upstands and flashings, and identifying any areas of membrane lift, cracking, or ponding. On larger roofs, a survey should also look at the condition of the deck beneath the membrane, which may require opening up a test section.
Ask for a written report that identifies the specific faults found, their likely cause, and the options available to address them. A survey that simply tells you the roof needs replacing without explaining why, or without describing the condition of each element, does not give you enough information to make a sound decision. Understanding the cause of the problem helps you avoid the same issues recurring after the work is done.
Commercial flat roof replacement in the UK typically costs between £70 and £120 per square metre depending on the system chosen, the condition of the existing deck, and access requirements. EPDM and single-ply systems sit at the lower end of that range for material cost, while fully adhered single-ply on complex roofs with many penetrations sits at the higher end. Repairs to localised damage are considerably cheaper, but only make sense where the majority of the existing roof surface is in reasonable condition.
Metal sheet roofing replacement for industrial buildings typically ranges from £40 to £90 per square metre for a profiled system, depending on the profile specified, insulation requirements, and whether the existing purlins need any work. These figures are indicative and will vary depending on the specifics of your building, access constraints, and current material costs. A proper survey is the only way to get accurate costs for your specific situation.
We cover Loddon and the wider south Norfolk area as part of our regular commercial roofing work out of Norwich. If you are a property owner or facilities manager with a commercial building in Loddon and you have concerns about your roof, call us to arrange a roof survey so we can give you a clear picture of what needs doing and what it will cost.
No obligation · We usually respond within 2 hours
Storm damage, active leak, damaged ridge - we aim to be on-site within 24 hours.
