Norwich Roofers provides commercial roofing installation, repair, and maintenance for businesses in Long Stratton and the surrounding south Norfolk area.
Commercial roofing is a different discipline from domestic work. The roof areas are larger, the consequences of a failure are greater, and the materials used are often entirely different from what you find on a house. We handle flat roofing, single-ply membranes, metal sheet roofing, and built-up felt systems.
Whatever system your building carries, the fundamentals of a well-executed job are the same: correct detailing at upstands, penetrations, and perimeter edges; adequate drainage falls; and materials suited to the span and usage of the structure. Get those right and a commercial roof can perform reliably for decades. Get them wrong and you will be dealing with leaks, insulation damage, and internal disruption far sooner than you should.
Most commercial buildings carry a low-pitched or flat roof, and the choice of system depends on the size of the area, the amount of foot traffic or plant equipment on the surface, and the existing substrate. A single-ply membrane such as TPO or PVC is now one of the most widely used options on new builds and full replacements. It goes down quickly, produces very few joints, and reflects solar heat. Built-up felt systems use multiple reinforced layers bonded together and are a proven option where budget is the primary concern. EPDM rubber is popular on smaller commercial roofs and extensions where a cold-applied, low-odour system suits the surroundings. Metal sheet roofing, whether standing seam or profiled sheeting, is standard on portal-frame warehouses and agricultural-style industrial units.
Each system has its own detailing requirements and its own failure points. Single-ply membranes can delaminate at seams if they are heat-welded in cold or damp conditions. Built-up felt fails at upstands and around outlets when the top cap splits or the adhesive bond breaks down. Metal sheet roofing corrodes at fixings and sealant lines over time, particularly where the coating is damaged during installation. Understanding these failure modes matters when you are assessing a contractor's proposed specification.
Choosing a commercial roofing contractor is not simply a matter of finding the lowest price. A poor installation on a large flat roof can cost far more to put right than the saving you made at the outset. The questions you ask before signing anything are the most important part of the process.
A credible contractor will give you a document that describes the proposed system in detail: the membrane brand and thickness, the insulation type and U-value if relevant, how upstands will be dressed, what happens at outlets and penetrations, and how the perimeter edge is fixed and weathered. A price without a specification gives you nothing to compare between quotes and nothing to hold a contractor to if the finished job falls short.
If a quote simply says "supply and fit flat roof" with a total figure, ask the contractor to expand on it in writing before you proceed. A contractor who is reluctant to do this is one to be cautious about.
Commercial roofing covers a wide range of building types. A contractor who installs single-ply on new retail units may not have experience working on an occupied school or a cold-store warehouse with a complex plant layout. Ask specifically whether they have carried out work on similar buildings, and ask to speak to a previous commercial client if possible.
The construction of the roof deck matters too. Concrete decks, steel decks, and timber decks all require different fixing methods and primers. A contractor who does not ask about your deck type before quoting is either guessing or planning to work it out on the day, neither of which is reassuring.
On a commercial building you may have staff, customers, or tenants below. Ask the contractor how they plan to stage the work, whether temporary waterproofing will be in place overnight, how waste and materials will be stored on site, and what happens if the weather causes a delay mid-job. A professional contractor will have a clear answer to each of these questions before work starts.
Temporary waterproofing at the end of each working day is particularly important. A large flat roof stripped of its existing covering and left exposed overnight is a liability if rain comes in. This is a conversation to have explicitly, not something to assume will be handled.
Large commercial roofs typically require scaffold, a MEWP (mobile elevated work platform), or a combination of both. Access costs can be a significant part of the overall job. Ask the contractor what access they intend to use, who is providing it, and whether it is included in the price or invoiced separately. Some contractors quote only the roofing labour and materials and present access costs as an addition once the job is awarded, which distorts your cost comparison.
On a re-roofing project, a proper pre-start survey should identify the condition of the existing deck, the state of any existing insulation, whether moisture is trapped within the build-up, and whether existing outlets and drainage are adequate for the new system. If insulation is wet it must generally be replaced, not simply overlaid, as trapped moisture will degrade the new system from below.
Thermal imaging can identify areas of wet insulation that are not visible to the eye. Not every job requires it, but on a large or complex roof it is worth asking whether the contractor proposes to use it and what will happen if wet patches are found during strip-out.
A flat roof is never truly flat. It needs a minimum fall of 1:80 in the finished surface to drain freely, and ideally more. On an existing building the fall is often fixed by the structure, but a competent contractor should tell you whether the current fall is adequate, whether tapered insulation can be used to improve drainage without raising the overall roof height, and where ponding water is currently occurring and why.
Ponding water is one of the most common causes of premature flat roof failure. It accelerates UV degradation of the membrane surface, adds load to the deck, and creates freeze-thaw stress in winter. A contractor who does not mention drainage falls in their survey is missing a fundamental part of the assessment.
The field of a flat roof rarely fails. Failures occur at the junctions: where the membrane meets a parapet wall, where a pipe or flue passes through the surface, or where a rooflight kerb is dressed. Ask the contractor to describe specifically how these details will be handled and what materials will be used. Upstands should typically be dressed to a height of at least 150mm above the finished roof level. A vague answer here is a warning sign.
When you have quotes from more than one contractor, make sure you are comparing the same specification. If one quote includes tapered insulation and another does not, they are not the same job. If one uses a 1.2mm membrane and another uses a 1.5mm membrane, the long-term performance will differ. Ask each contractor to clarify any points where their quote is less specific than another, so that your comparison is meaningful.
Price alone is a poor guide on a commercial roofing project. A roof installed on a flat roof for around £50-£90 per square metre (depending on system, specification, and access requirements) by a contractor who has properly assessed the deck, specified the right system, and detailed the junctions correctly will outperform a cheaper job that cuts corners on insulation depth or upstand height.
A commercial roof should be inspected at least once a year, and ideally in both spring and autumn. Inspections should cover the condition of the membrane surface, the state of seams and lap joints, upstand condition, outlet and gutter cleanliness, and any areas where foot traffic has caused surface damage. Catching a small split or a blocked outlet early prevents the kind of water ingress that damages insulation, deck structure, and the building interior.
A planned maintenance agreement gives you a record of inspections and any remedial work carried out, which is useful for building insurance and for any future property transaction. Ask any contractor you are considering whether they offer this and what it covers.
We cover Long Stratton and the south Norfolk area as part of our regular work out of Norwich. A good contractor will give you an honest assessment of your existing roof before recommending a course of action.
If you have a commercial property in Long Stratton that needs a survey, a repair, or a full replacement, call us to arrange a visit. A good contractor will look at the roof properly, explain what they find, and give you a clear written specification before any price is discussed.
No obligation · We usually respond within 2 hours
Storm damage, active leak, damaged ridge - we aim to be on-site within 24 hours.
