Dereham Roofers provides commercial roofing for businesses, landlords and industrial premises in Fakenham and the surrounding area.
Commercial roofing is a different discipline from domestic work. The buildings are larger, the consequences of a leak are greater, and the roof systems themselves are more varied. A flat roof on a retail unit behaves nothing like a pitched slate roof on a farm building, and the materials, detailing and maintenance requirements differ substantially between them.
On a commercial building, a failing roof can mean stock damaged, tenants unhappy, business disrupted and insurance claims complicated. Identifying the right repair or replacement strategy early is almost always cheaper than waiting until water has worked its way into the structure.
We work on commercial and industrial properties in Fakenham and the wider area around Dereham.
Most commercial properties fall into one of three broad categories when it comes to their roof: flat, pitched, or a combination of both. Understanding which category your building sits in helps you ask the right questions and evaluate quotes more confidently.
Many larger commercial buildings combine a flat roof main area with a pitched or cladded section. Each junction between roof types is a potential weak point where flashings and abutments need careful attention.
Because this is a common question and one that affects the cost and longevity of the work significantly, it is worth going through the main flat roofing materials in detail. There is no single correct answer. The right material depends on the building, the budget, the expected use of the roof surface, and how often the owner wants to revisit the roof for maintenance.
Mineral felt has been used on commercial flat roofs for decades. A built-up felt system typically uses three layers: a base layer bonded to the deck, an intermediate layer, and a cap sheet with a mineral surface. The cap sheet sheds water and provides some UV resistance.
Pros: Widely understood by roofers, materials are readily available, relatively low upfront cost, straightforward to repair if damaged.
Cons: Shorter service life than modern single-ply membranes - a standard felt system on a commercial roof may last 10 to 15 years before the cap sheet begins to crack, blister or allow water ingress. Felt is also less tolerant of foot traffic, so any roof with regular maintenance access can deteriorate faster. Joints and laps are potential failure points.
For a large commercial flat roof, a built-up felt system typically costs in the range of £40 to £70 per square metre installed, depending on the number of layers, the deck condition and the accessibility of the building.
EPDM (ethylene propylene diene monomer) is a synthetic rubber membrane that has become increasingly common on commercial flat roofs over the past 20 years. It is available in large sheets that can cover significant roof areas with very few seams, and it is glued or mechanically fixed to the deck.
Pros: Excellent long-term durability - well-installed EPDM can last 30 to 50 years in normal conditions. Very good resistance to UV, ozone and temperature variation. Seams, when properly bonded with the correct adhesive, are reliable. Straightforward to repair with compatible patch material if punctured.
Cons: Requires a competent installer who is familiar with the adhesive bonding system and seam preparation. A poorly bonded seam is a weak point. EPDM is typically black, which on a roof with significant solar gain can increase heat absorption into the building below - though white-faced and light-coloured variants are available. It is not the cheapest option upfront.
EPDM on a commercial roof typically costs in the range of £60 to £90 per square metre installed, depending on deck preparation required and roof complexity.
Single-ply membranes including TPO (thermoplastic polyolefin) and PVC (polyvinyl chloride) are hot-air welded at the seams rather than bonded with adhesive. This creates a continuous waterproof joint that is arguably more reliable than an adhesive lap in a demanding environment.
Pros: Seam strength is high when properly welded. Available in light colours, which can reduce heat gain. Long expected service life when correctly installed. Good resistance to ponding water.
Cons: Requires specialist equipment (hot-air welding tools) and a roofer trained in the specific system. Repair also requires compatible material and proper welding. PVC can become brittle over time if exposed to petroleum-based products, so it is not ideal near kitchen extract outlets or where oils may be present. Upfront cost is similar to or slightly above EPDM.
Single-ply systems typically cost in the range of £65 to £100 per square metre installed on a commercial building, with the variation driven largely by deck condition and any insulation upgrade included in the specification.
Any flat roof replacement is an opportunity to improve insulation. Current Building Regulations for commercial buildings set minimum U-values for flat roofs, and older buildings are frequently well below those standards. Adding rigid insulation board above the deck (a warm roof build-up) when you re-roof can make a meaningful difference to heating costs in a commercial building.
The cost of insulation boards adds to the overall project cost, but the payback in energy savings over the life of the roof makes it worth considering seriously. If a building is tenanted, better insulation also protects the tenant and reduces the risk of condensation-related damage to the structure.
Pitched roofs on commercial and agricultural buildings are most commonly covered in one of the following materials, each with its own cost profile and maintenance requirements.
Corrugated or profiled metal sheeting (steel or aluminium) and fibre cement sheeting are both common on agricultural barns and light industrial buildings. They are cost-effective, quick to install and relatively simple to repair by replacing individual sheets.
Metal sheeting has largely replaced asbestos cement on older agricultural buildings - if your building still has the original sheeting from the 1970s or 1980s, it may contain asbestos and requires specialist removal before any re-roofing work. This is a legal requirement and should never be skipped.
Modern galvanised or polyester-coated steel sheeting has a long service life. The coating protects against corrosion, though cut edges and fixing points can be vulnerable if not properly treated. Over-cladding an existing sheet roof (laying new sheets over the old) is sometimes possible, saving the cost of removal - though this is only appropriate when the structure and existing sheets are sound enough to support the additional load.
Composite panels consist of two metal skins with an insulating foam core bonded between them. They provide structural stiffness, weatherproofing and insulation in a single product. They are common on food production, cold storage and warehouse buildings where thermal performance and hygiene are priorities.
Replacement of composite panels is more expensive per square metre than single-skin sheeting, but the insulation value and airtightness they provide can be significant for temperature-controlled premises. Individual panels can often be replaced if damaged, without disturbing the whole roof.
Older commercial buildings, converted farmhouses used as offices, and retail premises in older market town centres sometimes have clay or concrete tile roofs, or natural slate. The maintenance and repair principles are the same as for domestic work, but the scale is larger and access equipment costs more on a commercial building. Ridge tiles, verge details and flashings to chimneys or parapet walls are common failure points on older tiled commercial roofs.
On flat roofs, the most common failure points are not the open field of membrane itself but the details: upstands where the roof meets a parapet wall, flashings where the roof meets a vertical surface, outlets and drains that become blocked, and laps between sheets or rolls of membrane that have lifted or debonded over time. A flat roof that has not been inspected for several years is likely to have at least some minor defects that, left alone, will become more serious.
On pitched roofs, slipped or broken tiles, damaged ridge or hip bedding, and deteriorated lead or mortar flashings around chimneys and abutments are the most frequent causes of leaks. On metal and fibre cement sheet roofs, failed or missing fixings, cracked sheets and deteriorated sealant at overlaps are the usual culprits.
Guttering on commercial buildings is often overlooked until it fails visibly. Blocked or leaking gutters on a large building can direct significant quantities of water against the wall or down into the building over time. Cast iron guttering on older buildings needs periodic repainting and joint resealing. UPVC and aluminium guttering on newer buildings is lower maintenance but can sag, pull away from fixings or develop splits at joints. Box gutters internal to a roof structure are a particular risk - they carry large volumes of water and a blockage or failure can cause serious internal damage quickly.
Wall cladding on industrial and agricultural buildings often needs attention at the same time as roof work. Profiled metal or fibre cement cladding panels can suffer from the same issues as roof sheeting: failed fixings, cracked panels, deteriorated sealant at joints and corners. On older buildings, flashings at the junction between wall cladding and the roof are a frequent source of water ingress.
Where cladding is in otherwise reasonable condition but looking dated or losing its surface finish, over-cladding with new profiled metal sheets can refresh the building without the cost of full removal. A structural assessment should confirm the existing wall framing can carry the additional weight before over-cladding is specified.
A proper commercial roof survey involves more than a look from ground level. For any meaningful assessment, a roofer needs to get onto the roof. On a flat roof, this means checking the membrane surface for cracks, blistering, ponding or delamination, inspecting all upstands and flashings, and clearing and checking all outlets. On a pitched roof, it means checking tile or sheet condition, ridge and hip details, flashings and any visible structural timbers where accessible.
You should expect a written breakdown of what was found, what needs immediate attention, what can wait, and a clear description of the recommended scope of work with the materials to be used. A quote that simply says "re-felt flat roof" without specifying the system, the number of layers, whether old felt is being stripped or over-clad, and how upstands and outlets will be finished is not a quote you can compare fairly against others.
Ask specifically: Will old material be stripped back to the deck? What condition is the deck expected to be in, and what happens if it needs replacing? What is the upstand height around the perimeter? Are all flashings included in the price? What is the drainage arrangement?
Commercial roofing costs vary significantly depending on the material, the size and accessibility of the roof, the condition of the existing structure, and what scaffolding or access equipment is required. As a rough guide for flat roof replacement on a commercial building:
These figures assume a reasonably sound deck. If the deck itself needs replacing - common on older flat roofs where water has been sitting for years - that adds cost, typically £20 to £40 per square metre depending on the deck type and thickness. Access equipment such as a cherry picker or scaffolding on a large commercial building can add several thousand pounds to a project.
For pitched roofs on commercial and agricultural buildings, profiled metal re-sheeting typically costs £30 to £60 per square metre. Composite panel replacement is considerably higher, often £80 to £150 per square metre or more depending on panel specification.
These are indicative figures based on typical current UK commercial roofing costs. Every building is different, and a survey is the only reliable way to produce an accurate figure.
We cover commercial and industrial properties in Fakenham and the surrounding towns and villages, working from our base in Dereham. The area includes a mix of agricultural premises, retail and light industrial units, and older commercial buildings that each bring their own roofing challenges.
If you manage a commercial property in Fakenham, own a portfolio of rental units, or are responsible for maintenance on an industrial or agricultural building, call us to arrange a roof survey. You should expect a roofer to get onto the roof, tell you honestly what they find, and give you a clear written breakdown of what work is needed and what it will cost.
For commercial roofing enquiries in Fakenham, call Dereham Roofers to arrange a site visit.
No obligation · We usually respond within 2 hours
Storm damage, active leak, damaged ridge - we aim to be on-site within 24 hours.
