Ely Roofers handles commercial roofing projects in Willingham from the initial site survey right through to clean-up, and this page walks you through exactly what that process looks like.
One of the most common sources of frustration for business owners and site managers is not knowing what is going to happen next on a roofing job - or why work that looked simple is taking longer than expected. This page explains, in plain terms, how a commercial roofing project is carried out from start to finish, and what a good job looks like at each stage.
The process described here applies broadly to flat roof refurbishments, single-ply membrane installations and metal sheet re-roofing on warehouses, offices, retail units and agricultural buildings in Willingham and nearby.
Before any work is priced or planned, a thorough inspection of the existing roof is necessary. This is not a quick look from a ladder. A proper commercial roof survey involves getting on the roof safely, inspecting the membrane or sheet surface across the full area, checking every flashing, upstand, outlet, ridge and lap, and examining the gutters and roof edge.
The condition of the roof deck or substrate beneath the surface matters as much as the surface itself. On a flat roof, insulation board that has absorbed water loses its structural value and will need replacing rather than just being covered over. On a metal-sheet building, purlins and rails that have corroded at fixing points may need attention before new sheeting goes on.
The survey should also look at the building's drainage - whether the outlets are correctly positioned, whether falls are adequate, and whether parapet or box gutters are holding debris or showing signs of overflow. A new membrane over a poorly draining roof will still pond water, which shortens the life of any system.
When comparing roofers, ask whether the site survey is free of charge. The findings are used to put together an accurate, itemised quote rather than a ballpark figure.
Once the survey is done, the right specification for the project can be proposed. For a flat roof, that means choosing the appropriate membrane system (EPDM, TPO or a high-performance torch-on felt), the insulation thickness, and the details for flashings, upstands and outlets. For a metal-sheet roof, it means specifying the correct profile, gauge and coating, and deciding whether to strip the existing sheets or overlay them.
The programme - the sequence and timing of the work - should be agreed before work starts, particularly for occupied buildings. On a working warehouse or office, it is usually possible to sequence the job in bays so that the interior is not fully exposed at any one time. Temporary protection sheeting can be used where the work must stop at the end of a day with the roof surface open.
If your business operates shifts or has specific periods when noise or access disruption would be a problem, this is the stage to discuss it. Work can often be scheduled around production hours, loading and dispatch windows, or customer-facing periods for retail premises.
A Risk Assessment and Method Statement (RAMS) is produced at this stage on request - most facilities managers and health and safety officers will need this before they allow work to begin on their site.
Safe access to a commercial roof is non-negotiable. On a large building, that typically means a scaffold system or a mobile elevated work platform (MEWP - a cherry picker or scissor lift). The access method is chosen based on the building height, the roof area, the type of work being done and the ground conditions around the building.
Materials - membrane rolls, insulation boards, metal sheets, fixings, sealants and equipment - are delivered to site and positioned so that repeated lifting and repositioning during the job is minimised. On large roofs, a crane lift or a materials hoist may be used to get heavy pallets of insulation board up without having to carry them up a ladder.
The area below the working zone is cordoned off during work, with signage and barriers to keep foot traffic clear of the drop zone. This is a basic site safety requirement and applies regardless of how large or small the project is.
Whether the existing surface is stripped or prepared in place depends on what the survey found and what has been agreed in the specification.
On a flat roof, a re-cover (overlaying the new membrane on top of the existing surface) is possible when the existing deck is sound and dry and the additional weight is within the structure's allowance. Stripping is necessary when the existing insulation is wet, the deck is damaged or the existing build-up is too thick to add another layer.
Stripping a commercial flat roof means removing the membrane, insulation and sometimes the deck boards, taking all the waste material down from the roof and disposing of it correctly. It adds time and cost but it is the only way to start from a clean, known substrate and to check the full condition of the structure beneath.
On a metal-sheet roof, stripping means removing each sheet, ridge cap, end cap and flashing, and taking down the liner and insulation layer if the building has one. The underlying steelwork is inspected and any corroded purlins or rails are repaired or replaced before new material goes on.
This is the main body of the work, and the sequence varies by material type.
For a single-ply flat roof, the insulation boards go down first, fixed mechanically or adhered to the deck. The membrane is then laid, starting from the low point of the roof and working toward the high point so that laps shed water in the right direction. Seams are hot-air welded or cold-bonded according to the system. Upstands at parapet walls are turned up and mechanically fixed, with the membrane terminated into a chase or covered by an aluminium or lead cap flashing. Every outlet is dressed with a purpose-made membrane collar, bonded to both the membrane and the outlet body.
For a built-up torch-on felt system, each layer is laid in a staggered bond pattern so no two laps coincide, and each layer is fully bonded to the one below. The number of layers and their specification depends on the design life required and the pitch of the roof.
For metal-sheet re-roofing, sheets are fixed from the eaves up, with each sheet overlapping the one below at the correct end-lap dimension for the pitch. Ridge caps, barge flashings and valley flashings are fixed last. Fixings go through the crown of the profile, not the valley, and every fixing receives a correctly seated EPDM sealing washer. Sealant tape is used at all laps where the profile geometry creates a gap.
Detailing around rooflights, vents, soil pipes, cable penetrations and any other roof projection is carried out at this stage. These details are the most time-consuming part of any commercial roofing job, but they are also the most important - a poorly dressed penetration is the most common route for water to get into a building on an otherwise sound roof.
Before access equipment is removed, the finished roof is inspected in full. Every seam, upstand, flashing, outlet and penetration is checked. On a welded single-ply membrane, seams are tested with a probe to confirm they are fully bonded. On a metal-sheet roof, every fixing is checked to ensure the sealing washer is seated correctly and not over-compressed.
This inspection is the last opportunity to identify and correct any detail before the access is gone. It is worth asking, as a client, to be present for this check or to receive a short written summary of what was inspected and the findings.
On completion, all waste material is removed from the site - this includes packaging, off-cuts, old membrane or sheet material from the strip, and any debris cleared from gutters during the job. The area around the building is left clear.
Gutters and outlets are left clear and checked to drain freely. Any areas of the building's interior that were covered with protective sheeting during the work are reinstated.
You should expect to receive a clear record of what was done, the materials used and any items identified during the job that were outside the original scope. This is particularly important for buildings that form part of a larger portfolio or for landlords managing commercial property in Willingham on behalf of tenants.
If you have a commercial roofing project in Willingham or nearby, it is worth asking the roofer for a site survey before you commit to anything. The roofer will assess the roof, explain what it needs and give you a clear picture of the work involved before you commit to anything.
No obligation · We usually respond within 2 hours
Storm damage, active leak, damaged ridge - we aim to be on-site within 24 hours.
