North Walsham Roofers carries out commercial roofing repairs, replacements, and new installations for businesses in Sheringham and across North Norfolk.
A failing commercial roof costs money in two ways: the repair itself, and the disruption to your business while the work is under way. Getting the job planned and executed properly from the start is the only way to control both. This page walks you through every stage of a commercial roofing project, from the initial inspection to final clean-up, so you know exactly what a well-run job looks like and what questions to ask before anyone gets on your roof.
We work on retail units, warehouses, agricultural buildings, workshops, and light-industrial premises throughout Sheringham and the surrounding North Norfolk area. Whether the roof is flat, pitched, or a mix of both, the process follows the same disciplined sequence.
Every commercial roofing project starts with a proper survey, not a glance from the car park. For a flat roof, that means walking the entire surface, checking for ponding, membrane bubbling, splits at seams, and failed upstands around plant equipment, rooflights, and parapet walls. On a pitched roof, we check the condition of the covering material, the ridge, hips and valleys, any lead or aluminium flashings, guttering, fascias, and the state of the supporting structure beneath.
A thorough survey on a commercial building can take an hour or more depending on size. Any contractor who gives you a firm price after five minutes on the ground is guessing. Ask specifically what they looked at and how they accessed the roof - a proper inspection usually requires a ladder or scaffold, not binoculars from below.
We also look for signs of ongoing water ingress inside the building during the survey: staining on ceilings, damp patches on walls near the eaves, and rust marks around fixings in steel-framed buildings. Internal evidence often tells you more about where a roof is actually failing than looking at the surface alone.
Once the survey is complete, you should receive a clear written report of what was found. This is not the same as a quote. A good report distinguishes between immediate problems, items that need monitoring, and work that is advisable to plan in the near future. That distinction matters: a business owner needs to know whether they can defer a section of re-roofing to the next financial year or whether a particular area must be addressed now to prevent structural damage.
Common flat roof problems identified at this stage include: delaminated felt layers where moisture has entered between plies, EPDM membranes that have pulled away from upstands due to thermal movement, failed sealant around pipe penetrations, and blocked outlet drains that have caused standing water to accelerate membrane breakdown. On pitched commercial roofs, common findings include cracked or slipped fibre-cement or profiled steel sheets, corroded fixings, and deteriorated ridge cappings that allow wind-driven rain to enter.
The report should also note any access constraints that will affect how the work is carried out - parapet heights, proximity to public footpaths, presence of roof-mounted equipment that needs protection or temporary relocation.
Once you have the survey report, the next conversation is about the scope of work and the materials to be used. For flat roofs, the two most common systems on commercial buildings are reinforced mineral-felt (built-up felt) and EPDM rubber membranes. Each has a different cost profile and a different installation process, and the right choice depends on the roof's configuration, the level of foot traffic it receives, and budget.
Built-up felt systems involve laying two or three plies of reinforced felt using hot-bonded or torch-on methods, finishing with a capsheet that reflects UV and resists foot traffic. A straightforward replacement on a flat commercial roof typically costs in the region of £70 to £120 per square metre depending on the number of layers specified and the complexity of detailing around upstands and penetrations. Larger areas tend to come down towards the lower end of that range.
EPDM rubber membranes are a single-layer system bonded or mechanically fixed to the deck. They are highly flexible, cope well with thermal movement, and are well suited to roofs with complex shapes or large numbers of penetrations. EPDM replacement on a commercial building typically costs in the region of £80 to £130 per square metre installed, again depending on area size and detail complexity.
For pitched commercial roofs - particularly agricultural and industrial buildings with profiled sheet coverings - the specification discussion usually centres on whether to overlay the existing sheeting with a new profile (cheaper, avoids the cost of stripping and disposing of the old material) or strip back to the purlins and start fresh. Overlaying is only appropriate when the underlying structure is sound; if purlins are corroded or deflecting, a full strip and re-roof is the right answer.
You should receive a written specification that names the exact materials to be used, the method of fixing, and how flashings and upstands will be detailed. Vague specs lead to disputes. If a contractor's quote simply says "re-roof flat roof in felt", ask them to specify exactly which product, how many layers, and how the perimeter will be finished.
On a commercial site, access planning is as important as the work itself. This stage covers scaffold or mobile elevated work platform (MEWP) requirements, the position of materials storage, protection of goods inside the building from dust and any temporary water ingress during stripping, and the timing of noisy operations around your business hours or your customers.
If the roof is over a trading area that stays open during the works, the programme needs to be agreed carefully. Stripping old felt or sheeting is noisy and generates debris. On a building where the inside must remain operational, we discuss sequencing the work in sections - stripping, renewing the deck if needed, and covering with the new membrane in manageable bays - so that no large area of roof is ever left exposed overnight.
Good planning at this stage also avoids surprises for neighbouring occupiers or the public. If the work requires a scaffold that temporarily narrows a footpath or delivery access, the relevant permissions need to be in place before work starts, not after.
On a re-roofing job, stripping the old covering reveals the true condition of the deck underneath. On flat roofs, decks are typically built from timber joists with plywood or OSB boarding, concrete, or metal decking. Common problems found at this point include: wet, delaminated plywood that will not hold fixings, isolated areas of rot in timber joists, and deflecting metal decking that has lost its profile due to corrosion.
Any deck defects found at strip-out need to be rectified before the new covering goes on. This is a point where the scope of work can increase from what was estimated at survey stage - not because the contractor has underquoted, but because some deck damage is genuinely not visible until the old covering is off. A responsible contractor will notify you immediately when this happens, explain the nature of the additional work, and give you a revised cost before proceeding. If a contractor proceeds with additional work without telling you, that is a problem.
On pitched buildings, strip-out often reveals corroded purlin cleats, loose bolts in the structural frame, or damaged insulation batts that need replacement. These findings should be photographed and reported to you before additional materials are ordered.
With the deck in confirmed good condition, the new membrane or covering goes on. For a felt system, the insulation board is laid first (tapered insulation can be used to improve fall towards outlets on a flat roof that previously pooled water), followed by the vapour control layer, insulation, and then the felt plies. Each layer is fully bonded to the one below. Upstands are taken up a minimum of 150mm above the finished roof surface and dressed back under the coping or cladding above.
For EPDM, the membrane is either fully adhered using a contact adhesive or mechanically fixed at the perimeter and laps. Seams between sheets are bonded using EPDM-specific tape and primer; the quality of these seams is the most critical part of the installation. Penetrations for pipes, cables, and drains are dressed using pre-formed EPDM boots and collar pieces rather than cut-and-patch methods, which produce a much more reliable result.
On profiled sheet roofs, new sheets are fixed through the crown of the corrugation using self-drilling fixings with EPDM washers, and laps are sealed. Ridge cappings and barge details are dressed in to give a weathertight finish.
Throughout installation, outlets and drains are kept clear. Nothing slows down a commercial roofing job and creates problems more reliably than blocked drainage that allows water to pond on an incomplete membrane.
Flashings are the interface between the roof covering and any vertical elements - parapet walls, upstands, rooflights, vents, and penetrations. They are where the majority of commercial roof leaks originate, and they deserve as much care as the main field of the roof.
Lead remains the benchmark flashing material for most pitched-roof applications on commercial buildings. Code 4 or Code 5 lead is used for most step and soaker situations, with Code 5 or 6 for cover flashings in exposed positions. Lead must be fixed with correct clip spacing and dressed to shape without over-working it; split lead is a common consequence of poor installation technique. Aluminium or code-equivalent lead-substitute materials are sometimes used on larger commercial projects where the weight of lead is a concern.
On flat roofs, upstand flashings are typically formed from the membrane itself, supported by a fillet at the base of the upstand, and terminated under a counter-flashing or coping. A common failure point is where the membrane meets a roof-mounted HVAC unit or extract fan: the collar must be fully integrated into the membrane, not just sealed over the top with mastic.
Before the scaffold comes down and access is lost, every outlet, hopper, and gutter run should be checked. Flat roofs need outlets at low points with adequate fall to reach them; 1:80 minimum fall is the general standard, though 1:40 is better. Outlets should be fitted with ballguards that can be removed for cleaning.
A sign-off inspection should be conducted with the building owner or their representative present, going over the completed roof area, inspecting all flashings and upstand details, checking outlets are clear and draining, and confirming that any temporary protection installed inside the building has been removed. At this point you should receive any relevant documentation for the materials used, including technical data sheets.
Commercial roofing generates significant waste: stripped felt, old insulation board, profiled sheeting, and associated fixings and battens. All of this needs to be taken off site to a licensed waste facility. Ask your contractor to confirm how waste will be removed and that it will not simply be tipped into a skip that sits on your site for weeks. Waste from a re-roofing job must be disposed of lawfully; if the old roof incorporated any insulation or adhesive materials from older buildings, there may also be asbestos considerations that require specialist disposal.
A professional contractor will leave the site clean, with no debris on the roof surface, in gutters, or on the ground around the building. The car park, yard, or access road should be swept before the team leaves.
To give you a realistic idea of the investment involved:
These are indicative ranges for typical current UK conditions. Every commercial building is different, and the only reliable way to get an accurate cost is a proper survey followed by a written specification and itemised quote.
Before you commit to a contractor for a commercial job in Sheringham or anywhere else in North Norfolk, ask these directly:
We cover Sheringham and North Norfolk for all commercial roofing work. If you have a commercial roof that is leaking, due for replacement, or simply overdue for a proper inspection, call us to arrange a survey. We will tell you honestly what we found, what needs doing now, and what can wait, with a written breakdown of the work involved.
No obligation · We usually respond within 2 hours
Storm damage, active leak, damaged ridge - we aim to be on-site within 24 hours.
